Vegetable Research 1983-1984, Commercial Vegetable Production Guides, North Willamette Research and Extension Center

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Vegetable Research at the North Willamette Agricultural Experiment Station, 1981-1982 On-line version of Oregon Agricultural Experiment Station Special Report 679, April, 1983
CONTENTS Introduction Overwinter Onion Variety Trials Overwinter Cauliflower Variety Trials Heat-Tolerant Cauliflower Variety Trials Spinach Variety Trials Pickling Pepper Evaluation Shallot Planting Density Trial Vegetable Production in "Solar Pods" In-field Forcing of Rhubarb Sweet Corn Response to Lime, Cu, and P Fertilizers Response of Vegetable Crops to Anticrustants Effect of Soil pH and N Fertilizers on Vegetable Stands Sewage Sludge as a Sweet Corn Fertilizer Chrome Tannery Waste as a Vegetable Crop Fertilizer Return to: AUTHOR: Dr. Delbert D. Hemphill, Jr., Assoc. Professor of Horticulture, has conducted research on vegetable crops culture and management since 1976 at Oregon State University's North Willamette Experiment Station, 15210 NE Miley Rd., Aurora, OR 97002-9543. Introduction to the Report A full-time program of vegetable crop research has been conducted at the North Willamette Experiment Station since 1976. The Station, a branch of the Oregon State University Agricultural Experiment Station, is just north of Aurora, a historic farming community 20 miles south of Portland, Oregon. The land is provided by Clackamas County, with facilities maintained by the university. Major vegetable research emphasis is on the needs of fresh market growers in the northern half of the Willamette River Valley, but research is also conducted on home garden and small farm intensive vegetable culture, processed vegetable crops, and the recycling of organic waste materials on cropland. Many research projects reported here involved cooperation with research and Extension service colleagues in the Oregon State University system and with area vegetable growers and processors. Their contributions are gratefully acknowledged. The financial support of the Collins Foundation of Portland, Oregon, the Northern Willamette Valley Horticultural Society, the Agricultural Research Foundation, the United States Environmental Protection Agency, the Tennessee Valley Authority, and the Oregon Danvers Onion Commission was essential to completing these projects and is greatly appreciated. The first five sections of this report concern trials which may help growers choose plant varieties most suitable for the northern Willamette Valley. The next four sections report research on cultural practices to improve yield and quality of several crops. Soil and plant tissue analysis associated with these experiments was performed by the Oregon State University Department of Soil Science. Two sections deal with research on improving stand establishment of vegetable crops. The final sections deal with the fertilizer value of organic waste products. Twenty crops from beans to tomatoes were involved in these experiments. This report is the third in a series of biannual reports initiated in 1979. DISCLAIMER: The use of trade names does not constitute an endorsement by the Oregon State University Agricultural Experiment Station. Always check pesticide labels for currently registered uses. Overwinter Onion Variety Trials Cooperator: Dr. N. S. Mansour, Department of Horticulture, Oregon State University, Corvallis The purpose of these experiments was to evaluate the performance of several onion (Allium cepa L.) cultivars in overwinter trials. The Willamette Valley appears to have a suitable climate for production of overwintered onions if bolting, disease, and weed control problems can be overcome. Previous experiments at the North Willamette Station have indicated that late August or early September planting dates are superior to later planting dates for maximum yields. With a June or July harvest, this might allow another crop on the onion ground both before planting and after harvest. Methods Plots were seeded on September 3, 1980, and September 15, 1981, in randomized complete block design with three (1980) or four (1981) replications. The plant stands were thinned to no more than 27/m. Plot size was 1 row x 6 m with 0.5 m between rows. The plot area was fertilized with 780 kg/ha (1980-81) or 1,110 kg/ha (1981-82) of 10-20-10 before planting and 4.5 kg/ha of propachlor herbicide was applied immediately after seeding. Additional N was applied as follows: 38 kg N/ha as ammonium nitrate in January 1981 and 112 kg N/ha in April 1981. In 1982, additional N was applied at 56 kg/ha in January, March and April; 4.5 kg/ha of propachlor was applied in November, January, and March of each crop year. Plots were hand-hoed as necessary. All plots were harvested on July 16, 1981, and July 8, 1982. Plant population at harvest was 22-26/m for most cultivars. Several cultivars were selected for storage tests. A sample of bulbs was held at 20°C mean temperature and 70 percent mean relative humidity in mesh bags. Rot and sprouting were evaluated in late October of each year. Results and Discussion 1980-1981 The 1980-81 winter was exceptionally mild, particularly in January. Most cultivars exhibited significant bolting. Since all cultivars were harvested on the same day, a few were over-mature and suffered some sunscald. However, very little regreening occurred. Some cultivars exhibited a small percentage of split bulb basal plates. This may have been caused by exposure to moisture after tops died down or to onion maggot damage. In 1981, the highest yielding cultivars in gross weight were Sweet Winter 1909, Red Cross, Keep Well, Senshyu Yellow Globe, OWY 100, and Willamette Sweet (Table 1). Largest mean bulb size was obtained with Sweet Winter 1909, Senshyu Yellow, Red Cross, Keep Well, and OWY 100. When the bulbs which had bolted were subtracted from the total yield, the rankings changed significantly. Highest estimated usable yield was obtained with Red Cross, followed by Keep Well, Dragon Eye, Senshyu Yellow 7991, Sweet Winter 1909, Willamette Sweet, OWY 42, and OWY 100. Imai also yielded very well, but the stand was not thinned and Imai plots were not randomized. Particularly high quality cultivars in color, lack of bolting and splits, and small neck size included Keep Well, Imai, Senshyu Yellow, and Red Cross (Table 2). Sweet Winter 1909 and Willamette Sweet were also impressive but had a high percentage of bolters. Red Cross was particularly mild-flavored. Cultivars considered overmature at harvest were Amber Express, Red Cross, Express Yellow, and Dragon Eye. At the end of three-month storage, Keep Well and OWY 100 exhibited the smallest degree of sprouting while 100 percent of the Red Cross bulbs had sprouted (Table 3). Storage rots, molds, and maggot damage were low for all cultivars except Keep Well. 1981-1982 The weather pattern in the 1981-82 winter was normal but no winterkill was observed. The only cultivars exhibiting any bolting were Cima (45%) and Walla Walla Sweet Super Early Strain (1%). The percentage of tops down at harvest ranged from 8 percent for Walla Walla Sweet Early Arbini strain to 95 percent for Top Keeper and Red Cross. However, no cultivar was considered overmature at harvest and there was very little sunscald or regreening. Highest yielding cultivars were Walla Walla Sweet (Super Early strain), Red Cross, and Top Keeper. Largest bulb size (mean weight of all bulbs) was obtained with the same three varieties. When ranked by yield of No. 1 bulbs (more than 7.5 cm diameter) only, the same three varieties had the highest yield (Table 4). Highest quality cultivars were Walla Walla Sweet Super Early, Top Keeper, Keep Well, Red Cross, OWl 100, and Willamette Sweet (Table 2). Yields were down somewhat from 1980-81 for cultivars tested both years. The reduction was caused mostly by smaller plant populations but bulb size did decline for a few cultivars. One hundred bulbs of seven cultivars were placed in storage immediately after harvest. Bulbs were examined at approximately monthly intervals and graded for firmness, rot, and sprouting (Table 5). Willamette Sweet, Top Keeper, and Keep Well had the lowest degree of storage rots and sprouting. Table 1. Yield and Mean Bulb Weight of Overwinter Onions, 1980-81 Estimated Mean bulb Total yield usable yield^Z Variety wt. (g) Rank (MT/ha) Rank (MT/ha) Rank Sweet Winter 1909 178 1 91.4 1 46^X 5 Senshyu Yellow 7985 170 2 96.9 4 38^X 10 Senshyu Yellow 7991 164 3 69.3 7 5 4 Red Cross 157 4 80.1 2 72 1 Keep Well 131 5* 77.6 3 66 2 OWY 100 131 5* 74.1 5 44 8 Dragon Eye 123 7 55.6 9 56 3 Willamette Sweet 120 8 69.7 6 45 6* OWY 50 118 9 66.5 8 30^X 13 AC 7952 116 10* 44.5 13 36 11* AC 7949 116 10* 39.3^Y 14 20^X 16* AC 7948 113 12 51.8 10 26^X 15 Express Yellow 102 13 39.2 15 39 9 AC 7950 99 14 46.6 11 20^X 16* Gladalan Brown 89 15 31.2^Y 18 16^X 18 Early Golden Globe 88 16 23.4^Y 19 12^X 19 Amber Express 86 17 36.3 16 36 11* Braeside 79 18 34.4 17 28 14 Pukukohe 76 19 12.8^Y 26 3^X 22 OWY 42 75 20 44.7 12 45 6* Kitami Ki 69 21 18.6^Y 23 0^W - Creamgold 67 22 21.8 20 0W - Sapporo Yellow 63 23 19.5^Y 22 0^W - Sapporo Ki 59 24 20.6^Y 21 0^W - Creamgold Early 58 25 14.3^Y 24 7^X 20* Early Locker Brown 48 26 13.5^Y 25 7^X 20* Imai 109^V -- 89.4^V --^V 80^V - LSD (0.05) 39 15.9 ^ZTotal yield less yield of bolters. ^YPoor stand, less than 16/meter. ^X50% or more bolters. ^W100% bolters. ^VNot included in replicated planting. Excess stand of ~ 36/m. Indicates a tie. Table 2. Sources and Quality Characteristics of Overwintered Onions, 1980-81 and 1981-82 Cultivar Bulb Scale Percent Neck Split Diameter Overall or line Source Maturity shape color bolted size bulbs (cm) rating 1980-81 AC 7948 1^Z 2^Y f-t^X 2^W 50 M^V 1^U - 2^T AC 7949 1 1 t 2 50 M 2 - 2 AC 7950 1 2 f-t 2 50-60 S 2 - 2 AC 7952 1 3 fg-g 2 20 S 2 - 2 Amber Express 2 1 f-t 1 0 S 3 - 2 Braeside 1 2 g-s 1.5 20 M 1 - 1-2 Creamgold 1 2 dg 1 100 M 1 - 1 Creamgold Early 1 2 g 1 50 M 1 - 1 Dragon Eye 2 1 f-g 2 0 S 2 - 3 Early Golden Globe 1 3 dg 2 50 M 1 - 2 Early Locker Brown 1 2 dg 1 50 M 1 - 1 Express Yellow 1 1 f-t 1.5 5-10 S 1 - 2 Gladalan Brown 1 2 dg 2 50 S 1.5 - 2 Imai 2 2 t 2.5 10 M 1.5 - 3 Keep Well 2 2 t-v 2.5 15 S 1.5 - 3 Kitami Ki 3 2 f-g 1.5 100 L 1 - 1 0WY 42 4 1 f 1 0 S 2.5 - 2 OWY 50 4 3 t-v 1.5 55 M 2 - 3 OWY 100 4 2 fg-t 2 40 M 2 - 3 Pukukohe 3 3 g 2 80 L 1 - 1 Red Cross 2 2 f red,poor^S 10 S 1.5 - 3 Sapporo Ki 3 3 s 3 100 L 1 - 1 Sapporo Yellow Globe 3 1 s 3 100 L 1 - 1 Senshyu Yellow 7985 1 3 t 2.5 50 S 2 - 3-4 Senshyu Yellow 7991 1 2 g-t 2 25 M 1.5 - 3-4 Sweet Winter 1909 4 2 ft 2 50 S 1.5 - 4 Willamette Sweet 4 2 fg 1.5 35 S 1.5 - 4 1981-82 Avanti 5 2 fg 1.5 0 S 3 5-7.5 2 Cima 5 3 fg 1.5 45 S 3 5 1 Imai 2 2 f 2 0 S 3 5-7.5 2 Keep Well 2 2 fg 2 0 M 3 7.5 4 OWY 100 4 2 fg 2 0 M 3 7.5 3 Red Cross 2 1 f red,fair 0 M 3 7.5-10 4 Senshyu Yellow 2 2 fg 2 0 M 3 5-7.5 3 Sweet Winter 1909 4 2 fg 1.5 0 M 3 5-10 3 Top Keeper 2 1 fg 3 0 S 3 7.5 4 Walla W. Early Arbini 3 3 g 1 0 L 3 5-7.5 1 Walla W. Super Early 3 2 g 1.5 1 M 3 7.5-10 3-4 Willamette Sweet 4 2 fg 1.5 0 M 3 5-10 3-4 ^Z1 = International Plant Breeders, Inc., 2 = Takii Seeds, 3 = Onion grower 4 = Dessert Seed Co., 5 = Keystone Seed Co. ^Yl = early, nearly all tops down at harvest, 2 = mid-season, 3 = late, over 50% tops standing at harvest. ^Xf = flat; fg = flat globe; g = globe; dg = deep or elongated globe; t = top; s = spindle; tv = top, variable. ^W1 = poor, light; 3 = dark yellow brown, uniform ^VS = small, M = medium, L = large. ^Ul = over 5%, 2 = 1-5%; 3 = less than 1%. ^T1 = poor, 5 = excellent. ^Sbleached, sunscald. Table 3. Storage Ratings of Overwinter Onions, 1980-81 Cultivars Percent Sprouted Percent Rotted (10/27/81) Dragon Eye 60 4 (very firm) Keep Well 8 60 (maggot infested) OWY 50 21 4 OWY 100 11 0 Red Cross 100 15 Sweet Winter 1909 45 25 (soft) Willamette Sweet 30 4 Table 4. Yield and Mean Bulb Weight of Overwinter Onions, 1981-82 Yield of all Mean bulb wt. Yield of No. 1^Z Cultivar bulbs(MT/ha) Rank all bulbs(g) Rank bulbs(MT/ha) Rank Avanti 38.7 6 131 6 23.2 5 Cima 15.8 12 60 12 0.5 12 Imai 25.2 10 96 10 8.8 11 Keep Well 41.4 5 145 4 23.0 6 OWY 100 38.7 6 125 7 18.9 8 Red Cross 55.4 2 162 2 43.2 2 Senshyu Yellow 31.5 9 108 9 11.7 9 Sweet Winter 1909 36.9 8 140 5 25.0 4 Top Keeper 50.9 3 156 3 38.9 3 Walla W. Early Arbini 24.3 11 84 11 9.0 10 Walla W. Super Early 63.7 1 207 1 54.7 1 Willamette Sweet 42.3 4 115 8 20.3 7 LSD(O.05) 16.2 60 13.6 ^ZNo. 1 bulbs have minimum diameter of 7.5 cm. Table 5. Storage Ratings of Overwinter Onions, 1981-82 Date Cultivar 8/11 9/20 10/21 Comments (8/11) % soft or rotten Keep Well 0 18 20 Firm OWY 100 17 19 27 ~½ getting soft Red Cross 20 29 34 Most firm, some sprouting Sweet Winter 1909 50 68 75 Very soft, some rot Top Keeper 11 14 14 Slightly soft Walla W. Super Early 19 22 48 Soft, some sprouting Willamette Sweet 4 6 7 Slightly soft Overwinter Cauliflower Trials* Cooperator: Dr. Paul Koepsell, Department of Botany and Plant Pathology, Oregon State University, Corvallis This report deals with the continuation of a series of tests of overwinter cauliflower (Brassica oleracea L. var. botrytis) production which began in 1977. Previous research established the feasibility of overwinter cauliflower production in the Willamette Valley and centered on cultivar and planting date trials, and the effect of spring-applied N on yields. The 1980-81 experiments reported here included a cultivar trial and a planting date trial. The 1981-82 experiments included cultivar testing, a planting date trial, and an evaluation of the effectiveness of metalaxyl fungicide in controlling mildew on cauliflower leaves and heads. Methods Plant spacing was 0.91 m x 0.45 m for all experiments except the mildew trial which was planted on 0.91 m x 0.61 m spacing. In each case, the plot areas received a broadcast, incorporated application of 900 kg/ha of 10-20-10, 2.2 kg B/ha, 55 kg/ha of Epsom salts, 11 kg/ha of Fritted trace elements, 0.8 kg/ha of trifluralin herbicide, and 1.1 kg/ha of fonofos insecticide. All trials were established with greenhouse-grown transplants. In the 1980-81 trials, an additional 112 kg N/ha as ammonium nitrate was sidedressed on March 2, 1981. The three 1980-81 cultivar trials were seeded on August 5, 15, and 22, and transplanted on September 11, 17, and 30, respectively. The 1980-81 planting date trials with Armado April cultivar were seeded on July 25, August 2, and August 15, and transplanted on September 5, 11, and 17, respectively. In the 1981-82 trials, an additional 56 kg N/ha as calcium nitrate was applied on January 25, 67 kg N/ha as ammonium nitrate on March 11, and 56 kg N/ha as ammonium nitrate on April 5, 1982. The single cultivar trial was seeded on July 30 and transplanted on September 2, 1981. In the planting date trial, Morse's March, Armado April, and Vision were seeded on July 15, July 30, and August 14, and transplanted on August 21, September 2, and September 21, 1981, respectively. The mildew trial with Armado April was seeded on August 14 and transplanted on September 21, 1981. Treatments included untreated check, one metalaxyl application at 1.1 kg/ha on September 22, 1981, and two applications of 1.1 kg/ha each on September 22, 1981, and January 20, 1982. The material was banded on the soil surface in granular form with four replications of each treatment in completely randomized design. Mildew ratings were taken at the single harvest on April 22, 1982. All other trials were harvested twice weekly in both years. Results and Discussion 1980-81 Armado April was the best of the early to mid-early cultivars in yield and quality (Table 1). Armado May and Maya were the superior mid-to-late lines. Because of the very mild winter, there was no winterkill and all cultivars made some growth throughout the winter. Early maturing varieties such as March and Superb Early White were exposed to night temperatures as low as -7°C (20°F) after curd formation had started. However, damage was slight. Cold weather in February and March retarded development of foliage; plant size was smaller than normal for all but the latest cultivars. Nearly all cultivars had a russeting of the leaves and curd, perhaps because of crane fly or Hylemya fugax larvae, mildew (Peronospora), or black rot (Xanthomonas). Quality was significantly reduced. This problem had not occurred in previous trials. Within the 12-day range (Table 2) for transplanting Armado April, there was no effect on yield or harvest date. Past trials have indicated a greater effect of planting date on mean head size. However, this trial supports the previous conclusion that a range of cultivars is a more effective means of spreading the harvest period than is a succession of planting dates. 1981-82 Twenty cultivars, with more than a two-month spread in maturity, were included in the trial. The 1981-82 winter was cold; on several nights, temperatures in the low teens (0 F) were recorded. Plants had essentially no growth during the winter, and a cold, dry spring further retarded plant development. Peak harvests averaged two weeks later in 1982 than in 1981. The earliest cultivars such as Superb Early White, March Early, Morse's March, Armado Quick, and Preminda did not size sufficiently to produce acceptable yields (Table 4), although each produced some heads with adequate curd quality. The mid-early Armado April also had low yields, although curd quality was good. The best combination of yield and quality occurred with mid-maturity cultivars such as Maya, Arminda, and Inca. Inca was included in the trials for the first time and looked promising for a mid-early to middle maturity line. Late cultivars such as Midsummer, June, and Vision had excellent gross yields but poor curd quality. In general, the earliest varieties suffered the greatest degree of winterkill. The effect of transplant date on yield and quality of three cultivars is seen in Table 5. For all three, mean head weight and gross yield declined with later transplant dates. Grade of Armado April also declined at the later dates. However, winterkill of the very early variety Morse's March was greater with the earlier plantings, confirming results obtained in 1979. Curds of Morse's March suffered freeze damage, particularly with the first planting. A one-month spread in seeding and transplant dates led to a 19-day spread in peak harvest for Morse's March, but had little or no influence on peak harvest of Armado April or Vision. However, planting date did affect first harvest of Armado April. Table 6 presents a summary of relative maturity of all cultivars included in trials in the last four years. Averages are for two or more years except as noted. The span of peak harvests from the earliest (Morse's March) to the latest cultivar (Vision) is nearly 60 days. Armado April was used as a standard for comparison, with other cultivars given in terms of days earlier or later maturity than Armado April. Metalaxyl treatments had no statistically significant effect on leaf mildew, curd mildew, or yield of Armado April cauliflower. Disease pressure was mild in 1982. No fly larvae were found in heads in 1982. Table 1. Overwinter Cauliflower Variety Trial, 1980-81. Harvest Summary Mean head Harvest range Est. gross Cultivar Source wt.(g) First Peak Last yield (MT/ha) A. Early Planting (transplanted 9/11) April 3Z 380 4/01 4/13 4/21 9.0 Armado April 5 650 3/16 4/01 4/10 5.5 Armado May 2 863 4/01 4/16 5/01 20.7 Armado Quick 5 547 3/19 3/23 4/01 13.1 Armado Tardo 2 NM^Y 4/10 NM NM NM Arminda 5 NM 4/01 NM NM NM Heralda 2 473 3/16 4/01 4/01 11.3 March Early 3 445 3/09 3/16 3/27 10.8 Markanta 2 NM 4/10 NM NM NM Preminda 2 522 3/16 4/01 4/10 12.6 B. Mid-Planting (transplanted 9/17) Aprilex 2 732 4/06 4/21 5/01 17.6 Armado Clio 5 775 4/21 5/01 5/14 18.7 March 2 387 3/09 3/09 4/01 9.2 Marchpast 2 619 3/23 4/01 4/16 15.0 Maya 1 690 4/24 4/27 5/11 16.7 Maystar 2 704 4/10 4/27 5/11 16.9 Midsummer 2 834 4/27 5/14 5/18 20.0 Mirado 5 479 4/21 5/01 5/05 11.5 Superb Early White 2 336 3/09 3/16 3/23 8.1 Vision 2 655 5/01 5/14 5/22 15.8 C. Late Planting (transplanted 9/30) Barrier Reef 4 201 4/01 4/13 4/27 4.7 CB-1 4 212 3/09 3/19 4/13 5.2 CB-4 4 142 3/09 3/12 4/24 3.5 290 4 207 3/12 3/27 4/16 5.0 1291 4 154 3/12 3/16 4/01 3.7 ^Z1=Bejo Zaden, 2=Elsoms, 3=Ferry Morse, 4=Royal Sluis, 5=Rogers Bros. ^YNM: not measured. Table 2. Effect of Planting Date on Yield and Harvest Period of Armado April, 1980-81 Transplant Mean weight Harvest dates Est. gross yield date (g/head) First Peak Last (Mt/ha) 9/05/80 665 3/23 4/01 4/13 16.0 9/11 656 3/16 4/06 4/10 15.8 9/17 623 3/16 4/01 4/10 14.9 Table 3. Description of Cultivars April: Few leaves, poor cover. Small heads but better than average curd quality when protected. Usually no leaves or bracts in head. Aprilex: Fair to good cover. Good curd quality. Yield only fair for mid- maturing cultivar. Armado April: Good cover on larger plants. Excellent curd quality on well-sized plants. Fair yield. Best of early cultivars. Armado Clio: Fair to good cover. Good yields. Tends to have leaves in curd. Multiple stems. Armado May: Good cover. Fair to good yield. Tendency to leaves in head but good curd quality. Armado Quick: Poor cover, small size. Too early for cold winter/ spring. Heads small but curd quality usually better than average. Armado Tardo: Good cover, but yield and head size small for mid maturing variety. Multiple stems. Arminda: Good cover, yield, head size. Very good curd quality. Barrier Reef (Rogers Bros.): Fair cover, small plants. Not true overwinter type. Heralda: Fair cover. Poor protection from wrapper leaves but older leaves form stovepipe. Poor yield, fair quality. Igloo (Keystone Seed Co.): Headed in December, frozen out in January. Not adapted for overwinter culture. Inca: Good cover, good plant size for early to mid-maturity range. Good yield, head size, quality. June: Good cover and plant size. Late maturing. Poor curd quality. "Fuzzy" curds, leaves and bracts in head. March Early: Too early to size sufficiently. Poor yield, curd quality. Thirty percent winterkill. Marchpast: Good cover, but small to medium size plants. Good head size for mid-early variety. Fifteen percent winterkill. Very good curd quality. Markanta: Good plant size but only fair cover. Low yield for midmaturity variety. Very prone to green stems. Fifteen percent winterkill. Maya: Good cover,yield, head size. Good curd quality. Best of mid- maturing varieties. Maystar: Good cover and yield, but only fair curd quality. Low density heads. Midsummer:Good cover, large plants. Late maturing. Multiple stems. Large heads but very poor curd quality: "fuzzy", bracts in head. Mirado: Good cover, medium size plants. Fair yield. Conical, knobby curds. Morse's March: Poor cover, small plants. Too early to size sufficiently. Poor curd quality. Average of 35 percent winterkill. Preminda (Armado Primo): Poor cover and plant size. Too early to size sufficiently. Average curd quality. Strong Osena (Keystone Seed Co.): Headed in December, frozen out in January. Not adapted for overwinter culture. Superb Early White: Poor cover and plant size. Too early to size sufficiently. Poor curd quality. Thirty percent winterkill. Vision: Good cover, large plants. Late maturing. Excellent gross yields but curd quality poor. "Fuzzy" curds, bracts in head. Multiple stems. Superior to other late varieties. Table 4. Overwinter Cauliflower Variety Trial, 1981-82. Harvest Summary Est. Mean Gross Yield of Harvest range head yield #1 heads MeanY Cultivar Source First Peak Last wt.(g) (MT/ha) (MT/ha) grade April 3^Z 4/23 4/30 5/07 555 11.7 7.9 1.4 Aprilex 2 4/30 5/03 5/17 565 13.7 8.6 1.4 Armado April 2,4 4/02 4/13 4/23 492 10.4 6.5 1.4 Armado Clio 2,4 5/03 5/14 5/17 666 19.1 9.9 1.6 Armado May 2,4 4/16 4/30 5/11 613 15.8 9.2 1.6 Armado Quick 2,4 3/16 4/13 4/26 329 7.0 4.1 1.5 Armado Tardo 2,4 4/26 5/07 5/14 486 13.9 8.1 1.5 Arminda 4 4/30 5/07 5/14 858 15.6 11.3 1.3 Inca 1 4/16 4/23 5/07 750 18.0 14.4 1.4 June 2 5/15 5/17 5/28 1011 23.0 1.8 1.9 March Early 3 3/29 3/29 4/13 144 2.0 0.5 1.8 Marchpast 2 4/13 4/23 4/26 712 11.7 10.4 1.2 Markanta 2,1 4/23 5/03 5/07 588 11.5 5.9 1.7 Maya 1,2 4/30 5/07 5/17 846 17.8 12.4 1.4 Maystar 2 4/26 5/07 5/14 699 18.9 9.9 1.6 Midsummer 2 5/11 5/21 5/28 923 16.7 0.0 2.0 Morse's March 2 3/16 3/16 4/02 236 3.6 1.0 1.8 Preminda 2,4 3/19 4/20 4/23 381 9.2 5.0 1.5 Superb Early White 2 3/16 3/29 4/23 207 3.2 0.8 1.8 Vision 2 5/25 5/25 5/28 897 25.0 5.9 1.8 ^Z1 = Bejo Zaden 2 = Elsoms Seeds Ltd. 3 = Ferry Morse 4 = Royal Sluis. When two sources are listed, the seed lot from the first source listed was used in the trial. ^YGrade 1.0 = all heads free of defects; tight, white curd. All heads given a score of either 1 or 2. Grade 2.0; all unacceptable. Table 5. Effect of Planting Date on Yield, Grade, and Winter Mortality of Three Winter Cauliflower Cultivars, 1981-82 Est. Trans- Mean gross Yield of Winter- plant Harvest head yield #1 heads kill Mean Cultivar date First Peak Last wt.(g) (MT/ha) (MT/ha) (%) grade Morse's March 8/21 3/10 3/10 3/29 554 3.4 0.0 50 2.0^Z 9/12 3/16 3/16 4/02 236 3.6 1.0 31 1.8 9/21 3/19 3/29 3/29 158 2.3 0.5 13 1.9 Armado April 8/21 3/19 4/13 4/16 611 12.8 12.2 13 1.1 9/12 4/02 4/13 4/23 492 10.4 6.5 0 1.4 9/21 4/13 4/16 4/26 384 5.9 2.7 19 1.6 Vision 8/21 5/21 5/25 5/25 910 34.2 13.0 6 1.7 9/12 5/25 5/25 5/28 897 25.0 5.9 0 1.8 9/21 5/21 5/25 5/28 688 12.4 4.3 0 1.7 ^ZFreeze-damaged curds on early maturing heads. Table 6. Relative Maturity of Overwinter Cauliflower Cultivars Compared to Armado April Days^Z earlier or later than A. April Cultivars -20 to -11 Morse's March, March Early, Superb Early White -10 to -3 Armado Quick, Preminda -2 to +2 Heralda^Y, Armado April +3 to +10 Marchpast, Barrier Reef^Y, Inca^Y +11 to +20 April, Armado May, Aprilex, Markanta +21 to +30 ArmindaY, Armado Tardo, Maystar, Maya, Mirado^Y, Armado Clio, Pinnacle^Y Over +30 June^Y, Midsummer, Vision _____________________________________________________________________________________ ^ZWithin each category, varieties listed in order of maturity. ^YBased on one year of observations. Heat Tolerant Cauliflower Trials The purpose of these trials was to obtain and evaluate cultivars of cauliflower for summer harvest. The major desired quality is heat tolerance: the ability to withstand high temperatures without ricing and to maintain the high curd quality typical of autumn-harvested cauliflower. A second desired quality is long wrapper leaves for self-blanching. Tying leaves must be minimized. Fully satisfactory cultivars have not been available to Oregon growers. It would be helpful for both fresh market and processors to have a high quality summer crop. The possibility exists for double cropping, particularly if combined with overwintered cauliflower. The research involved comparing common autumn-harvested types with named cultivars or lines from several seed companies which might be useful for a summer crop. Methods In 1981, 37 cultivars or lines of cauliflower were seeded in a glasshouse on April 10 and were transplanted to the field on May 15. In 1982, seeding date for the 24 cultivars was April 19 and transplant date was May 24. Land preparation in both years included broadcast and incorporation of 1,120 kg/ha of 10-20-10, 56 kg/ha Epsom salts, 2 kg/ha boron, 6 kg/ha of Fritted trace elements, 0.84 kg/ha trifluralin, and 2 kg/ha fonofos. Diazinon, as a 1 kg/ha drench, was applied in June when root maggot damage became apparent. In 1981, N was sidedressed as ammonium nitrate at 56 kg/ha on June 23. In 1982, an additional 45 kg N/ha was applied as calcium nitrate on June 15 and 45 kg N/ha as ammonium nitrate on June 29. Plant spacing was 0.91 m x 0.45 m. Each variety was replicated three times in randomized block design. Heads were harvested at three-day intervals from July 6 to July 30. Results 1981 Weather during the 1981 harvest period was not very conducive to poor curd quality. High temperatures ranged from 94 to 98°F on July 3-5, immediately before first harvest on July 6. This may have lowered quality for early varieties such as Alert, King, and Snow Crown. Temperatures were then mild until July 15-17, when highs of 82 to 88° were reached. Temperatures then remained under 80° F until the very end of the harvest period. For the entire harvest period, the high temperature averaged 72°, the low averaged 53°. Highest yields were obtained with Snowcrown, Alert, King, and Dok Elgon, but of these only Dok Elgon had acceptable curd quality (Table 1). The other three cultivars were slightly overmature at first harvest. Best quality curds were found in Dominant, Maveron, Self-blanche, Silverstar, Dok Elgon, Delira, Snowball 16, and White Summer. Quality was based on white color, firmness, lack of leaves or bracts in the curd, and depth of curd. 1982 Weather conditions during harvest were moderately conducive to poor curd quality. From July 6 to July 30, the mean maximum temperature was 81°, exceeding 85°F seven times. The mean minimum temperature was 52°F. This may have contributed to the generally lower percentage of high quality heads harvested in 1982 as compared to 1981. Highest gross yields were obtained with Snowball Y and two seed lots of Rijk Zwaan Type 165 (Table 2). Snowball Y failed to produce high quality heads, and its yield of Grade #1 heads was below average. Highest yields of Grade #l heads were from the two seedlots of Type 165, Silverstar, White Summer, and Dominant. Of the 24 cultivars in the 1982 trial, 18 were also evaluated in 1981 and 5 were evaluated in 1978. Head weights were generally greater in 1982 than in 1981. Cultivars performing well in both 1981 and 1982 included Dominant, Silverstar, and White Summer. Those performing average or better in 1978 or 1981 but poorly in 1982 included Dok Elgon, Delira, Marva Record, Maveron, Self-blanche, Snowball Y, Snowball 16, Venus, and White Empress. Consistently average cultivars included Imperial 10-6, Type 338A, and King. Repeated trials will be necessary to evaluate the longterm potential of these cultivars. Descriptions of cultivars are found in Table 3. Table 1. Yield and Grade of Summer Cauliflower, 1981 Harvest % #1^Z Mean head Yield of #1 Gross yield Cultivar span heads wt.(g) heads (MT/ha) (MT/ha) Alert 7/6 (all)^Y 0 882 0.0 21.4 Begum 7/6-7/14 31 506 3.2 12.2 Balanza 7/6-7/10 27 596 3.6 14.4 Climax 7/6-7/17 44 373 4.3 9.0 Dok Elgon 7/10-7/17 71 709 13.1 17.1 Delira 7/6-7/17 75 519 9.9 12.6 Dominant 7/10-7/20 77 640 11.0 15.5 Extra Early Snowball 7/6-7/10 44 542 5.6 13.1 Fortados 7/6-7/10 50 529 7.2 12.9 Hornstar 7/6-7/14 19 369 1.6 9.0 Hormade 7/6-7/17 50 463 7.4 11.3 Imperial 10-6 7/6-7/17 50 631 8.1 15.3 Idol Original 7/6-7/14 22 491 2.5 11.0 Kibo Giant 7/6-7/14 13 658 1.8 15.8 King 7/6 (all)^Y 31 819 7.7 19.8 Lawyna 7/17-7/27 0 386 0.0 8.8 Le Cerf 7/10-7/17 13 257 1.4 6.3 Lero 7/17-7/20 0 216 0.0 5.2 Marva Record 7/6-7/10 53 623 8.8 15.1 Maveron 7/6-7/17 81 494 9.5 11.9 MSU 817 All riced before 7/6, no measurements made Nevada 7/6-7/17 50 341 4.3 8.3 Polar Ice 7/10-7/27 13 496 1.4 12.8 Self-blanche 7/6-7/20 80 517 10.1 12.4 Silverstar 7/10-7/20 81 537 10.6 13.0 Snowball Y 7/6-7/17 60 641 8.1 15.5 Snowball 16 7/6-7/20 69 484 8.8 11.7 Snowball 123 7/6-7/14 63 446 7.9 10.8 Snowcrown 7/6 (all)^Y 13 1009 2.3 24.3 Snowmound 7/6-7/20 56 385 5.9 9.2 Torina 7/6-7/20 7 512 0.5 12.4 Venus 7/6-7/14 63 646 10.5 15.5 White Empress 7/6-7/10 50 514 7.5 14.9 White Summer 7/6-7/20 69 484 9.0 11.7 White Top 7/6-7/17 40 430 6.5 10.3 Type 338A 7/6-7/17 50 504 5.7 12.1 Type 404 Y 7/17-7/27 0 244 0.0 5.4 ^ZTo achieve grade #1, heads must weigh at least 400g, have white curds, and be free of defects such as leaves in head, loose or knobby curds. ^YSlightly overmature at first harvest. Table 2. Yield and Grade of Summer Cauliflower, 1982 Gross Yield of Harvest span Mean head yield #1 heads %, #1 Cultivar First Peak Last wt. (g) (MT/ha) (MT/ha) heads Alert 7/06 7/08 7/13 486 10.8 5.4 55 Dok Elgon 7/16 7/19 7/26 777 16.9 4.5 22 Delira 7/13 7/19 7/20 558 12.8 4.3 26 Dominant 7/15 7/19 7/21 793 18.0 8.8 40 Imperial10-6 7/13 7/19 7/21 797 18.4 4.7 32 King 7/13 7/13 7/15 959 18.7 6.8 38 Marva Record 7/13 7/15 7/15 850 18.9 1.1 6 Matra 7/15 7/19 7/23 698 16.9 1.6 8 Maveron 7/13 7/13 7/15 677 15.8 2.3 14 Self-blanche 7/13 7/19 7/21 706 15.1 1.4 7 Snowball Y 7/15 7/19 7/26 899 21.8 4.5 17 Snowball 16 7/13 7/19 7/21 836 18.4 0.0 0 Snowball 42 7/13 7/19 7/30 813 19.8 2.3 13 Snowball 76 7/13 7/19 7/30 856 19.8 2.3 9 Snowcrown 7/06 7/13 7/13 469 12.2 1.4 18 Silverstar 7/13 7/19 7/30 701 16.5 14.0 83 Suprimax 7/13 7/15 7/09 706 17.1 4.1 21 Venus 7/06 7/13 7/15 761 18.4 5.0 23 White Empress 7/08 7/13 7/19 572 14.0 1.6 13 White Summer 7/13 7/15 7/30 648 16.5 9.9 60 Type 165 Lot 2320 7/19 7/21 7/30 920 20.5 19.8 95 Type 165 Lot 9238 7/19 7/26 7/30 894 20.9 17.8 91 Type 338A 7/08 7/13 7/21 581 13.6 6.8 43 LSD (.05) 155 4.1 4.5 18 Table 3. Sources of Cauliflower Varieties and Comments, 1981 and 1982 Cultivar Source Comments Alert 8^Z Plants medium size. Upright stovepipe but few wrapper leaves. Harvested overmature in 1981. Leaves in curd. Begum 1 Plants medium size, upright. Small bracts in heads. Some purple curds. Balanza 1 Plants large, spreading. Rices easily. Climax 1 Plants medium size, upright. Small heads, fair quality. Dok Elgon 3 Plants medium size, upright. Large head, tight curds, good quality. Some leaves in curd. Mid-maturity. Delira 3 Plants large; wrinkled, dark green leaves. Small to medium heads, good quality, but leaves in head. Mid-early. Dominant 3 Plants medium size, spreading. Medium to large heads with good cover. Good quality. Mid-maturity. Extra Early Snowball 8 Plants small, spreading. Medium heads, Fair quality. Rice easily. Fortados 7 Plants small, spreading. Early heads, good quality. Later heads yellow. Hornstar 1 Plants small, spreading. Small heads. Hormade 1 Plants medium size, spreading. Side shoots. Many heads with purple curd. Imperial 10-6 4 Plants large, spreading. Good quality but rices easily; large heads with some leaves in curd. Mid-early. Idol Original 8 Plants medium size, upright. Ricey, yellow and purple curds. Kibo Giant 3 Plants large, upright. Large heads, purple curds. King 3 Plants large, upright. Large heads. Rices easily, bracts in curd. Mid-early. Lawyna 3 Plants medium size, spreading. Small heads. Knobby, conical florets. Le Cerf 3 Plants medium size, spreading. Small heads, poor quality curds. Lero 1 Plants small, spreading. Small heads. Poor quality curds. Marva-Record 2 Plants medium size with good cover. Medium to large heads. Matra 7 Medium size, semi-spreading plant. Fair curd cover. Fair head size and yield but leaves, bracts in curd. Mid-maturity. Maveron 1 Plants medium size, spreading. Small to medium heads, good quality curd with leaves and bracts. Mid-early. MSU 817 12 Plants small, upright, but poor curd cover. Heads small, ricey. Nevada 3 Plants medium size, upright. Small heads, fair to good quality curd. Polar Ice 5 Plants medium size, upright. Small to medium heads, small bracts in curd. Self-blanche 4 Plants medium size, stovepipe, good cover but few wrapper leaves. Fair quality curds, sometimes fuzzy, yellow. Mid-maturity. Silverstar 10 Plants small, spreading. Medium heads. Very good curd quality. Mid-late. Snowball Y 4 Plants medium large, spreading. Medium to large head. Average curd quality. Mid-late maturity. Snowball 16 9 Plants medium large, upright. Head small to medium size. Snowball 42 13 Medium-large semi-upright plants with good cover. Good head size and yield but bracts, leaves in curd. Mid-late. Snowball 76 13 Medium-large spreading plants with fairly good curd cover. Good head size and yield but bracts, leaves in curd. Mid-late. Snowball 123 4 Plants medium large, upright. Heads small. Good curd quality. Snowcrown 6 Plants medium large, spreading. Heads large, overmature. Purple curds. Early. Snowmound 8 Plants medium size, spreading. Small heads. Good curd quality. Suprimax 7 Medium size semi-upright with fair cover. Riced easily. Mid-early. Torina 2 Plants medium size, upright, poor curd cover. Small to medium heads; conical, knobby curds. Venus 1 Plants medium size, upright. Large heads, good curd quality but bracts in curd. Early. White Empress 14 Plants medium size, spreading. Medium heads, some with bracts. Fuzzy, ricey. White Summer 8 Plants medium large, upright, dark green. Average size heads with good quality. Large spread in maturity. White Top 8 Plants medium size, upright. Many discolored curds. Type 165, 2320 and 9238 10 Medium large semi-upright with good cover. Excellent yield and curd quality. Late maturity. Type 338A 11 Plants medium size, upright. Medium heads. Fair curd quality. Type 404 Y 11 Plants medium large, spreading. Small heads. Very late. Leaves in head. ^Z1=A.R. Zwaan, 2=Bejo Zaden, 3=Elsoms Seeds Ltd., 4=Harris Seeds, 5=Hurst, Gunson, Cooper, Taber Ltd., 6=Burpee Seeds, 7=Royal Sluis, 8=Stokes, 9=Northrup King, 10=Rijk Zwaan, ll=Roger Bros., 12=Michigan State University, 13=Ferry Morse, 14=Moran Spinach Variety Trials Cooperators: Dr. N.S. Mansour, Department of Horticulture, Oregon State University, Corvallis; C.A. Boyle, D. Liere, and R. Schulbach, Agripac, Inc. In northern states, spinach is normally planted in early spring for late spring harvest or in summer for autumn harvest. Spring plantings are often limited by the difficulty of working cold, wet soils and many cultivars bolt in the long daylengths of late spring. Summer crops must be established during periods of very high soil temperature and low soil moisture and require frequent irrigation. Some Willamette Valley growers have successfully planted spinach in late summer for autumn harvest or in autumn for early spring harvest. Ideally, stands can be established during periods of relatively favorable soil temperature and moisture and plants harvested before long days induce bolting. Either system would allow for double cropping (three crops in two years) when combined with beans, corn, or other vegetables, and would allow for more efficient use of processing facilities. These trials were undertaken to evaluate several spinach cultivars or lines for autumn or overwinter crops and to obtain better knowledge of the cultural problems involved, particularly weed control in the overwinter crop. Methods In both autumn and overwinter trials, 24 cultivars or lines of spinach were seeded on 1.0 m raised beds of Willamette silt loam, pH 6.0. Planting dates were August 24 and October 3, 1981. Plot areas received a broadcast, incorporated application of 840 kg/ha of 10-20-10 and 4.5 kg/ha of cycloate before final bed shaping. Four replications were planted in randomized complete block design with two rows on each bed. Plot size was 3 m2. Clorpropham at 1.1 kg/ha was applied after seeding. Calcium nitrate was sidedressed on the autumn trial plots at 34 kg N/ha on September 10 and 30, 1981, and on the overwinter plots at 56 kg N/ha on January 25, March 11, and April 2, 1982. Fluid lime at 1,120 kg CaC03/ha was applied to the overwinter trial on January 18, 1982. Autumn trials were harvested and rated on October 14 (XPH 1285) and October 20, 1981; overwinter trials were rated on April 16 and harvested on April 28, 1982. Results and Discussion Overall growth and quality were somewhat disappointing in both trials. This may have been caused by slightly marginal soil pH and resultant nutritional problems. The yellow-tipped leaves on most varieties probably were caused by low pH. In addition to yields and plant height, several quality characteristics were evaluated on a fivepoint scale. A deep green color is an important characteristic for either processing or fresh market and is related to soil pH and nitrogen uptake. Unfortunately, deep green color is also associated with the savoy or crinkle leaf character which is not desirable in spinach for processing. Savoy types are difficult to clean but semi-savoy types may be acceptable. Erect, rather than prostrate, growth habit is important for achieving a high percentage cut out from the field, whether machine or hand-harvested. Prostrate leaves also accumulate more dirt. The ideal cultivar, then, would be high-yielding, non-bolting, erect, deep green, and with large, uniform leaves. The most outstanding line in the autumn trial was XPH 1285 from Asgrow. It yielded well, had long, large, upright leaves, good uniformity, and average or better color, but not deep green. Other promising lines included Early Hybrid 424 (except for mediocre color), 7R, ACX61, and St. Helens (Table 1). Bolting was not a problem in the autumn trial because of short days and low temperatures. The cycloate-clorpropham herbicide combination provided excellent weed control and cultivation was not needed. Disease and insect problems were minimal and no fungicides or insecticides were applied. In view of the reduced bolting tendency, autumn spinach may be a better choice than spring planting for processing spinach in the Willamette Valley. Table 1. Yield, Plant Height at Harvest, and Quality Factors of Autumn-harvested Spinach, 1981 Leaf^Y Cultivar or Yield Height Color^Z Vigor^Y Uni- Leaf^Y Growth^W Line (MT/ha) (cm) formity size habit 7R 11.4 15 3.3 3.0 2.7 2.3 3.3 AC X59 8.5 12 2.3 2.0 3.7 2.3 3.0 AC X61 11.1 16 3.0 4.0 3.7 4.0 3.7 Baker 5.5 11 3.3 1.7 3.7 3.0 1.3 Big Leaf 10.6 13 2.3 2.0 2.0 1.3 2.7 Chinook 10.1 13 4.3 2.7 3.0 3.0 2.3 Dynamo 13.0 16 1.7 3.7 4.0 3.3 3.0 Early Hybrid 7 12.7 14 4.0 3.0 3.0 2.3 3.0 Early Hybrid 424 15.7 18 2.7 4.3 4.0 4.0 4.0 18D-X7 12.7 17 2.0 3.7 3.3 3.3 3.7 18D-X44 12.7 12 3.0 2.0 2.0 2.3 2.3 18D-X49 13.0 14 3.0 2.7 1.3 2.7 2.7 18D-X56 11.4 14 2.7 2.3 2.0 3.0 2.0 18D-X57 7.8 12 2.7 2.0 1.7 2.3 2.7 18D-X59 9.1 14 3.0 2.0 3.0 2.7 2.3 18D-X61 9.5 11 3.7 1.7 2.7 1.7 2.0 18D-X62 11.7 14 2.3 2.0 1.7 2.3 2.0 High Pack 11.4 14 2.3 3.3 2.7 3.0 2.3 Melody 7.8 11 4.3 1.3 4.0 2.0 1.3 R 2578 9.1 11 3.3 1.0 4.0 1.3 2.3 St. Helens 11.4 15 2.7 3.3 4.0 3.0 3.7 Symphony 13.0 13 3.7 1.7 4.0 1.7 3.0 XPH 1285 20.9 32 3.3 4.7 4.3 3.3 4.7 XP 3057 10.8 14 3.0 2.3 3.7 2.3 2.7 LSD (0.05) 2.6 6 0.8 0.9 1.2 1.0 1.0 ^Zl = pale, yellow; 5 = dark, green ^Y1 = least vigorous or uniform; 5 = most vigorous or uniform ^X1 = smallest; 5 = largest ^W1 = prostrate; 5 = upright The most outstanding line in the overwinter trial was also XPH 1285. However, it tended to bolt early. Other promising lines included 7R, Chinook, Emerald Queen (except for mediocre color), FM 18DX7 (except for color), Hybrid 424, and Symphony (Table 2). Lines exhibiting significant bolting at time of harvest included XPH 1285, 7R, Chinook, FM18DX44, FM18DX62, and Jake. Lines performing well in both autumn and overwinter trials were XPH 1285, Hybrid 424 and 7R. The cycloate - clorproham herbicide combination provided good weed control and only one spring cultivation was needed. Disease problems were moderate, with mildew the major problem. Despite the intensive management which may be needed, overwinter spinach production on well-drained soils may also be a feasible alternative to spring plantings for processing spinach. Major advantages are better planting conditions, earlier harvest, and reduced bolting. Disadvantages include the necessity to keep the field weed free and fertilized during periods when field operations are difficult. Harvest would likely occur under muddy conditions. Table 2. Yield, Plant Height at Harvest, and Quality Characteristics of Overwintered Spinach, 1981-82 Leaf Plant Yield Height Color^Z Vigor^Z unifor- unifor- Leaf^Y Growth^X Cultivar (MT/ha) (cm) mity mity size habit 7R 19.8 17 4.0 4.0 3.8 3.5 4.0 4.0 ACX59 12.9 11 2.8 2.8 3.5 2.8 2.8 2.5 ACX61 7.4 12 3.3 2.8 3.8 2.8 3.8 3.0 Avon 12.3 13 4.0 2.5 3.5 2.3 3.0 2.8 Baker 11.9 12 3.8 3.0 3.3 3.0 3.3 2.5 Big Leaf 13.4 12 3.0 2.5 3.0 2.5 2.5 2.8 Chinook 16.8 17 3.0 3.8 4.0 3.0 3.8 3.5 Dynamo 9.5 11 1.3 2.8 3.3 3.0 3.5 2.3 Early Hybrid 7 14.4 12 3.5 2.5 3.5 2.5 2.5 3.3 Early Hybrid 424 14.7 17 2.8 3.5 3.5 3.8 3.3 4.0 Emerald Queen 18.8 17 2.8 3.3 3.8 3.5 3.3 3.3 18DX7 18.3 18 2.8 3.8 3.8 3.0 3.8 3.0 18DX44 15.6 17 2.0 3.5 3.8 2.8 3.3 3.8 18DX56 11.1 12 3.0 2.8 2.8 2.8 3.0 2.8 18DX59 14.7 14 3.3 3.0 3.8 3.0 3.3 3.3 18DX61 13.6 11 3.8 2.3 2.8 2.3 2.3 2.3 18DX62 13.1 14 2.8 3.3 3.3 2.5 3.3 3.3 High Pack 13.1 15 2.8 2.5 3.8 3.8 3.3 3.3 Jake 16.1 14 3.5 2.8 3.8 3.0 2.5 4.0 R 2578 10.6 13 2.8 2.8 3.0 2.0 2.8 3.3 St. Helens 9.6 14 3.5 2.5 4.0 2.8 3.0 3.5 Symphony 14.1 14 4.0 3.0 4.3 3.5 2.8 3.8 XPH 1285 38.1 32 3.5 5.0^W 5.0 5.0 4.0 5.0 XP 3057 13.4 13 3.0 3.3 3.5 2.3 3.5 3.0 LSD(0.05) 3.2 4 1.1 1.3 0.8 1.0 0.9 1.1 ^Zl = pale, yellow green; 5 = dark green ^Y1 = least vigorous, uniform etc.; 5 = most vigorous, uniform, etc. ^X1 = prostrate, 5 = upright ^Wbolting Table 3. Source, Leaf Type, and Comments on Spinach Lines, 1981-82 Cultivar or Source^Z Leaf type Comments line 7R 1,2 semi-savoy Fairly good variety, small leaves. Just started to bolt in overwinter trial. AC X59 1 smooth Average. Leaves had yellow tips. AC X61 1 smooth Above average in all categories but poor stand. Avon^Y 1 semi-savoy Variable color but usually good. Baker 1 smooth Prostrate, lacking in vigor. Big Leaf ? slight savoy Small (!) leaves with yellow tips. Chinook 1 semi-savoy Good color except for yellow tips. Average otherwise. Bolting just starting in overwinter trial. Dynamo 5 smooth to Fairly good all around except for slight savoy poor color. Early Hyb. 7 1 savoy Pretty good color. Leaves too savoy for processing. Early Hyb. 424 1,4 smooth Better than average except for color. Emerald Queen^Y 5 smooth Variable color, otherwise above average. FM18D-X7 3 smooth Above average except for poor color. FM18D-X44 3 semi-savoy Leaves had yellow tips. Bolting just starting in overwinter trial. FM18D-X49^X 3 slight savoy Average. FM18D-X56 3 semi-savoy Average. Leaves had yellow tips. FM18D-X57^X 3 slight savoy Leaves had yellow tips FM18D-X59 3 slight savoy Leaves had yellow tips, but above average quality overwintered. FM18D-X61 3 savoy Better than average color, but poor otherwise. FM18D-X62 3 semi-savoy Poor-fair overall. Bolting just starting in overwinter trials. High Pack 2 slight savoy Lower leaves pale, others with yellow tips. Broad, triangular leaves. Jake^Y 1 slight savoy Better than average color. Seed stalks just forming. Melody^X 4 very savoy Excellent color, lacks vigor, too savoy for processing. R 2578 5 semi-savoy Small leaves with yellow tips. Variable. St. Helens 1 very smooth Above average variety, but color and yield only fair. Symphony 5 smooth Small leaves with yellow tips. XPH 1285 2 very smooth Long petioles, very early, tendency to bolt early. Long, triangular leaves. XP 3057 2 smooth to Yellow-tipped leaves, average. slight savoy ^Z1 = Alf Christianson, 2 = Asgrow, 3 = Ferry Morse, 4 = Harris, 5 = Rogers Bros. Seed lot used in trial was from first source listed. ^YOverwinter trial only. ^XAutumn trial only. For the 21 lines included in both the autumn and overwinter trials, 16 yielded more as an overwinter crop than as a fall crop, although harvest was at similar maturity. Some of this yield increase may have been caused by better stands. However, overall yields and plant vigor were still somewhat disappointing when compared to yields in some growing areas. Low soil pH probably contributed to low yields and marginal quality of some lines. In particular, the cultivars Big Leaf and Hybrid 424 have performed better at higher soil pH. Pickling Pepper Trial Local growers and processors could benefit by introduction of new crops into the Willamette Valley. Currently, processors of pickling peppers import their needs from more southerly growing areas. Local production has been thought to be limited by lack of adapted cultivars, poor yields, or quality problems. The following trial was undertaken to evaluate the yield potential of four pepper cultivars collected by the Steinfeld's Co., and to investigate the use of ethephon as a ripening agent for cherry type peppers. Methods All cultivars were seeded in a greenhouse on March 25, 1982, and transplanted to the field on May 19 on 0.91 m x 0.45 m spacing. The plot area had received a broadcast, incorporated application of 1,120 kg/ha of 10-20-10 before planting. Soil pH in the plot area averaged 5.7. Transplants were watered in with a transplant solution, diphenamid was applied for weed control at 4.5 kg/ha, and the plots were immediately irrigated by overhead sprinkler. Following establishment, plots were irrigated weekly. A sidedress application of 224 kg N/ha as calcium nitrate was made on June 15. Plots were cultivated three times during the growing season. Plots were hand-harvested on five occasions between early August and early October. Only full-sized fruit were harvested. Only fully red-ripe fruit of cherry type peppers were harvested. On August 20, half the plots of Peto Sweet Cherry were sprayed with 0.1% ethephon at a rate of 700 liters of spray/ha. Plots were in randomized block design with four replications of each cultivar (8 reps for Peto Cherry). Results and Discussion Total yields ranged from 14.6 MT/ha (cherry types) to nearly 50 MT/ha for Petite Sirah, a small banana wax type (Table 1). In each case, the figures represent usable yield since rotten fruit was discarded and immature fruit was not picked. In the case of two cherry types, 5-6 MT/ha of green fruit remained at the final harvest. No fungicides were used in this trial. Fruit rot problems were insignificant for Petite Sirah and Cascabella but caused significant yield reduction for the cherry types. More than half the fruit of the cherry types was discarded at the last harvest. Rough and cracked fruit was also a problem with both cherry types. The Harris and Peto cherry types were identical for all practical purposes. Ethephon treatment did not significantly (P?0.05) increase the total yield of Peto Sweet Cherry (Table 1), but did greatly increase yield at the first two harvests (Table 2). Thus, ethephon promoted early ripening. Ethephon had no effect on fruit size at the first two harvests, but did reduce fruit size at the final harvest (Table 3). Fruit size of the other cultivars did not vary in a consistent fashion during the harvest season. All cultivars set fruit unevenly and multiple pickings were necessary to harvest all fruit at the proper stage of maturity (Table 4). Since the plants are brittle and easily broken, each harvest did substantial damage to the crop. The later-maturing cherry types had a more concentrated maturity but early ripening fruit did not hold well. All cultivars continued to bloom and set on fruit during the entire season. For the cherry types, the most practical approach may be to spray with ethephon when the fruit first starts to ripen and then harvest all the ripe fruit in one or two pickings. A once-over harvest would be possible if the processor can grade out and utilize green fruit. Yields of no more than 12 MT/ha should be expected for once-over harvest. Table 1. Total Yield and Mean Fruit Weight of Pickling Peppers Cultivar Total yield Mean fruit Comments (MT/ha) wt.(g) Petite Sirah 49.9 7.9 Small, mild, banana wax, up to 10 cm long. Cascabella 33.8 4.5 Miniature hot banana, 2.5 to 5 cm, very hot when red ripe. Harris Cherry Sweet 15.1 14.4 Mild, spherical, 2-3 cm diam. fruit. Peto Sweet Cherry 14.6 14.8 Mild, spherical, 2-3 cm diam. fruit. Peto Sweet Cherry 18.9 13.7 Early ripening stimulated & ethephonZ by ethephon. LSD (0.05) 6.1 0.6 ^ZSprayed before first harvest with ethephon. Table 2. Yield of Ethephon-treated and Control Peto Sweet Cherry Peppers on Each Harvest Date, 1982 Harvest date Peto Cherry Peto Cherry, ethephon --------------MT/ha------------------- 8/27 1.4 2.9 9/10 3.0 8.4 10/11 10.2 7.6 Table 3. Mean Fruit Weight of Peppers Picked on Each Harvest Date Harvest Cultivars date Petite Cascabella Harris Peto Peto Cherry + Sirah Cherry Cherry ethephon -------------------------g------------------------------ 8/05 8.2 - - - - 8/18 7.8 5.1 - - - 8/27 6.9 4.0 14.4 13.9 13.6 9/10 7.4 4.5 14.6 14.9 15.1 10/11 9.1 4.4 14.3 15.5 12.3 Table 4. Percent of Total Pepper Yield Picked on Each Harvest Date Harvest Cultivars date Petite Cascabella Harris Peto Peto Cherry + Sirah Cherry Cherry ethephon ------------------------%--------------------------- 8/5 15 - - - - 8/18 24 32 - - - 8/27 16 20 15 11 16 9/10 19 20 22 21 44 10/11 26 28 63 68 40 Shallot Planting Density Trial Shallots may be grown as an overwinter or spring-planted crop in the Willamette Valley. Major cultural problems in this crop include weed and disease control, effect of planting dates on yield, maturity, and degree of bolting, and the effects of size of, planting stock and planting density on yield and bulb size at harvest. This study was designed to investigate the effects of three planting densities and two bulb sizes on the total yield and mean bulb weight at harvest and on the number of bulbs produced per bulb planted. Methods Bulbs of two sizes (small, mean weight of 12.2g; large, mean weight of 27.7g) were planted at three densities (low, 15 cm x 61 cm; medium, 15 cm x 30 cm; high, 15 cm x 15 cm) on September 16, 1981 in a factorial experiment with six treatment combinations. Plots were arranged in randomized complete block design with three replications. Individual plots consisted of four 3-meter rows. Records were taken from the two middle rows of each plot. The fertilizer program included 1,120 kg/ha of 10-20-10 broadcast and incorporated before planting, and 56 kg/ha of N as ammonium nitrate applied on January 20, March 11, and April 14, 1982, for a total N application of 280 kg/ha. DCPA herbicide at 10 kg/ha was applied immediately after planting. Propachlor at 4.5 kg/ha was applied on January 20 and March 19, 1982, following cultivation. Plots were harvested on July 29, 1982. Results Total yield on an area basis was significantly affected by both bulb size at planting (P<0.05) and by spacing or density (P<0.01). Planting larger bulbs produced about a 12% yield increase when compared with smaller planting stock (Table 1). A fourfold increase in planting density produced a doubling of yield. Yield per unit area did not increase proportionally to the increase in planting density since both bulb weight and the number of bulbs produced/bulb planted decreased at higher densities. Planting large bulbs increased the number of bulbs produced per unit area since the number of bulbs produced/bulb planted was greater with the larger planting stock. However, mean bulb weight tended to decrease slightly (difference not significant at 5% level) with the larger planting stock. For production of planting stock, high planting densities would be preferable to achieve maximum yields. For markets that require large bulb size, low planting density and small planting stock size should favor production of large bulbs, but with greatly reduced total yield. Table 1. Yield of Overwintered Shallots in Response to Bulb Size and Planting Density Treatment Total bulb Mean bulb # bulbs produced # bulbs produced yield (kg/m2) wt. (g) per square meter per bulb planter low density, small bulbs 3.33 18.5 199 16.6 low density, large bulbs 3.82 17.3 222 20.6 medium density small bulbs 4.21 14.2 295 13.7 medium density, large bulbs 5.44 13.2 407 18.9 high density, small bulbs 6.91 13.5 510 11.9 high density, large bulbs 7.25 11.4 636 14.8 LSD (0.05) 1.17 2.9 82 3.5 Mean, small bulbs 4.80 15.4 328 14.1 Mean, large bulbs 5.49 14.0 422 18.1 LSD (0.05) 0.67 NS^Z 47 2.0 Mean, low density 3.58 17.9 200 18.6 Mean, medium density 4.85 13.8 351 16.3 Mean, high density 7.11 12.5 574 13.3 LSD(0.05) 0.82 2.1 58 2.5 ^ZNS: no significant difference at 5% level. Difference significant at 10% level. Vegetable Production in "Solar Pods" The Willamette Valley of western Oregon is well known for production of a wide range of quality vegetables. Commercial, large-scale production of warm-weather vegetables such as tomatoes and melons is possible but is limited by competition from more favorable growing areas. However, for the home gardener or small market gardener, production of almost any vegetable crop except tropicals is possible in the long, mild growing season of the Willamette Valley. Major limiting factors are late spring frosts, insufficient heat for some warm-weather crops, and low night temperatures. Production of the warm weather crops can be greatly enhanced by the use of greenhouse-grown transplants, unheated glasshouses and cold-frames, and various plastic structures. For cool-season but non-winter hardy crops such as leafy greens, root crops, and cole crops, the growing season can also be extended with protective structures. Some of these crops, e.g. lettuce, can be successfully overwintered with minimal frost protection. In 1980, the Collins Foundation funded a two-year trial of passive solar heating methods for extending the growing season of both warm- and cool-season vegetables. One system studied was the "Solar Pods®" of Solar Survival, Inc. Methods The Solar Pods consisted of 1.22m x 2.44m raised-bed cold frames covered by a double glazing of fiberglass. The sides and bottom of the Pods were insulated with 5 cm of plastic foam insulation. Effective growing height for plants was 56 cm, limiting the type of vegetables which could be grown before removal of the fiberglass cover in May. During the first winter, one of the two Pods contained a half-exposed 55-gallon black drum filled with water as a potential passive solar heat sink. During the second winter, the drum was replaced by solar panels from The Vegetable Factory, Inc. which contain a liquid with a melting point of 29°C. Pods were generally opened during sunny periods if the ambient temperature exceeded 13°C. This prevented excessive heat buildup and allowed greater solar radiation to reach the crops. Pod covers were always open from May through September. Results Pods strikingly increased mean maximum air temperatures. For example, in January 1981, the mean daily maximum air temperature recorded at the North Willamette Station weather recording facility was 10°C, but the Pod maximum averaged 29°C. Effect of the Pods on mean low temperatures was quite small, a 1.7°C average increase. However, the Pods provided substantial frost protection on the coldest nights: the lowest temperature ever recorded in the Pods was -4°C on a night when ambient air temperature fell to -11°C. Frost sensitive crops such as lettuce and beans were not injured, except along the outer edges of the growing area. Soil temperatures at two-inch depth also were affected. Pod maximum soil temperatures averaged 12 C higher than ambient; low temperatures were increased 4°C. Soil temperatures in the Pods never reached the freezing point and were usually adequate for growth of cool-season crops. Cropping History A complete cropping history for the Solar Pods is in Table 1. Crops grown in the Pods in 22 months included bush bean (5 crops), carrot (4), Chinese cabbage (1), cucumber (1), head lettuce (4), leaf lettuce (5), bunching onion (2), parsley (2), bell pepper (1), radish (4), spinach (3), squash (1), and tomato (2). No more than seven of these crops occupied the Pods at any one time. All Pod crops were grown from seed. Use of transplants would have decreased production time considerably for several crops. Total usable production for the two Pods was 223 kg in slightly less than 22 months or 25.6 kg/m /yr. Solar Pod costs in late 1980 were $160 each for materials and plans, plus shipping and assembly, or in excess of $53/m of growing area. However, similar structures could be constructed from local materials for less than $100 material cost or about $32/m². Discussion A large number of crops are well adapted to Pod culture. The Pods are most effectively used to start vegetable transplants in early spring or to grow cool season crops through the winter. Neither the water-filled drum nor the solar panels significantly affected Pod air or soil temperatures. A solid melting at 50 to 70°F may be needed for effective heat storage. The primary advantages of the Pods are that they provide significant frost protection and raise air and soil temperatures during daylight hours sufficiently that good crop growth can occur. Pod drawbacks include 1) extremely high initial cost, 2) daily care is needed to lift and close Pod covers to prevent excessive heat, 3) crop height is limited, 4) poor light transmission through the fiberglass covers. Given the high initial cost and labor requirement, Solar Pods are economically feasible only for year-around home gardening or for production of very high value crops. Table 1. Solar Pod Cropping History, 1980-1982 Planting Harvest Yield for two date date Crops pods (kg) Comments 12/17/80 2/27/81 'Michihli' Ch. cabbage 4.1 Good quality and appearance. 'Ithaca' head lettuce 4.6 Only fair quality, bitter. 'Waldmann's', 'R-1' 5.7 Only fair quality, soft, 'Deep Red, and (total) elongated. 'Deep Red' failed 'Oak Leaf' leaf lettuce to achieve normal red color. 'Melody' spinach 2.0 Small leaf size, fair quality. 'Inca' radish 1.8 Excellent quality. 2/27/81 7/09/81 'Pixie' tomato 7.8 Normal quality, yield. In production 7 weeks early. 'White scallop' squash 13.7 Excellent yield and quality. First harvest 5/10 'Bush whopper' cucumber 6.5 Good quality. First harvest on 5/16. 'Nantes' carrot 6.7 Small carrots, normal top growth. 'Tendercrop'bean 2.7 Good quality but should have been harvested earlier. 'Ithaca' lettuce 6.2 Normal field quality. 'Banquet' parsley 1.1 Good quality. 2/27/81 5/05/81 'Inca' radish 3.2 Good quality, appearance. 5/05/81 7/09/81 'Inca' radish 2.7 Reduced bulb size, quality. Too hot? 7/09/81 9/29/81 'Ithaca' lettuce 10.0 Immature. 'Nantes' carrot 19.3 Immature. 'Melody' spinach 11.8 Planted too early for best quality. 'Spartan Arrow' bean 16.1 Good yield and quality bean. 'Banquet' parsley 0.8 Needed more time. 'Japanese bunching' onion 9.1 Good quality. 9/30/81-10/18/81 (Soil sterilized with Vapam) 10/18/81 3/10/82 'Tendercrop' bean 2.7 Quality adequate. Yield limited by low temp. 'Melody' spinach 5.0 Fair quality. 'Nantes' carrot 5.0 Excellent crop, some bolting. 'Ithaca' lettuce 5.6 Adequate quality. 'Japanese bunching' onion 7.6 Good quality. 'Inca' radish 4.6 Overmature. 3/15/82 7/20/82 'R-5' lettuce 3.8 Good yield and quality. 'Waldmann's' lettuce 3.4 Good yield, slightly pale 'Spartan Arrow' bean 8.3 Excellent quality and yield 3/15/82 10/05/82 'Keystone Giant' pepper 4.0 Good yield, small size. 'GSV80-25' tomato 11.7 Good quality, fruit like 'Pixie'. 7/20/82 10/05/82 'Spartan Arrow' bean 11.5 Good quality and yield. 'Nantes' carrot 5.6 Good quality. 'Waldmann's' lettuce 4.3 Good quality, deep color. _________________________________________________________________________________________ Total production by crop: bean, 41.3; carrot, 36.6; Chinese cabbage, 4.1; cucumber, 6.6; head lettuce, 26.4; leaf lettuce, 20.8; bunching onion, 16.7; parsley, 1.9; pepper, 4.0; radish, 12.4; spinach, 18.8; squash, 13.7; tomato 19.5. Total production: 222.6 kg on 4.83m² (usable space) in 1.80 years = 25.6 kg/m²/year fresh weight yield. In-Field Forcing of Rhubarb Rhubarb growers would benefit from an inexpensive, reliable method for forcing crowns into early production and increasing yields. Early harvests of high quality spears allow growers to take advantage of the usually higher early season prices. Currently, two methods are commonly used to bring rhubarb into early production. In the first, crowns are dug, removed to a hot house, and forced under etiolated conditions. In the second, rows of crowns are covered in the field with clear plastic mulch which increases air and soil temperatures and results in early spear growth. The first method has the disadvantage that the crowns are exhausted and the field must be replanted. In the second method there are the additional costs of plastic purchase and removal and possible difficulty in laying the plastic during unfavorable weather conditions. Gibberellic acid (GA) has been used to stimulate growth of hot house-forced rhubarb, but has not been used successfully in the field. Lack of response in the field may have been caused by non-etiolated conditions or poor uptake of GA by crowns or buds. Successful GA treatment of rhubarb may depend upon soil- and debris-free buds or may require injection. The following experiments were designed to determine whether yield and earliness of field grown rhubarb could be increased by GA injection directly into crowns, including single and multiple injection points, or by a spray treatment of previously washed crowns. Methods In 1981, treatments were applied to crowns in a commercial planting on February 20, as buds were just beginning to break. A total of 10 ml of each treatment solution was injected into three separate buds (approximately 3-4 ml/bud) per crown. Plots consisted of four crowns each and treatments were replicated 10 times. Treatments were: 1) 10% ethanol in water (control), 2) 800 ppm GA in 10% ethanol, and 3) 4,000 ppm GA in 10% ethanol. One day following application of treatments, five replicates were covered with clear plastic mulch. Non-covered plots were harvested on 3/31/81. In 1982, the treatments were applied to the North Willamette Experiment Station rhubarb variety planting. Treatments included 1) water-injected controls, 2) 10 ml/crown of a 500 ppm GA3 solution injected at three sites (approximately 3 ml each) per crown, 3) 10 ml/crown of 2,000 ppm GA3 at three sites, 4) 10 ml/crown of 2,000 ppm GA3 at one site per crown, 5) water-injected and covered with 2 mil clear polyethylene mulch, 6) poly mulch plus 2,000 ppm GA3 at three sites, 7) 2,000 ppm GA, 10 ml, three sites, injected in late spring, rather than winter, to once-harvested crowns, 8) washed crowns, sprayed with 100 ml of 50 ppm GA3, 9) washed crowns sprayed with 100 ml of 500 ppm GA3. All treatments were applied on February 12 except 7), applied on June 11. Each type of treatment (rates of injection, single vs. multiple injection, sprays, and late applications) had its own set of controls. All experiments were in randomized block design with two crowns/plot and three to six replications of each treatment. Plastic-covered plots were harvested on March 18; GA application rate, and single vs. multiple injection treatments were harvested on April 8, spray treatments on April 23, and the late injection plots were harveste on July 25, 1982. No fertilizer or herbicide treatments were made in 1982 before the final harvest. Plots were not irrigated during the period of the experiment. Results - 1981 GA markedly increased the total weight of rhubarb cut in a once-over harvest in 1981 (Table 1). The lower rate significantly increased yield and the higher rate further increased total yield but not marketable yield. Marketable spears were defined as at least 20 cm length and free of serious blemishes. Gibberellin treatment had very little effect on the number of spears harvested (Table 1), but significantly increased average spear weight and length (Table 1). Response to GA was greatest within 5 to 7 cm of the injection site. Untreated areas of the crown showed little response, indicating very little translocation of the GA. Quality of the spears from treated crowns was adequate, comparing favorably with quality of plastic-forced spears. There was some scarring of spears originating at the injection point, apparently caused by mechanical damage to the bud. The plastic-covered plots were not harvested but GA treatment effects on spear length were evident. However, the degree of GA response under plastic appeared smaller because of increased growth of spears on control crowns. Table 1. Effect of GA on Rhubarb Yield and Spear Size, 1981 Total Marketable #Spears/ Mean Mean spear Treatment yield yield crown spear length (kg/plot) (kg/plot) wt.(g) (cm) Control 2.73 0.00 103 19 10.7 GA, 800ppm 5.20 1.60 134 32 21.6 GA, 4,000ppm 7.27 1.95 150 36 24.1 LSD (0.05) 1.83 0.46 NS 6 4.2 Results - 1982 Rate of Injection As in 1981, injection of GA3 at three sites per crown increased total yield at once-over harvest on April 8, 1982, increased the number of spears/crown, increased mean spear weight, and increased the number of spears exceeding 20 cm in length (Tables 2 to 5). However, very little increase occurred with the 500 ppm solution, particularly for the 'Crimson' variety. For each of the above parameters, there were statistically significant increases only with the 2,000 ppm solution. In 1981, both 800 and 4,000 ppm solutions caused significant increases in yield. Apparently, injection of at least an 800 ppm solution or 8 mg GA/crown is necessary for an effective response. Environmental conditions may also affect the dose response, however. Combination with Plastic Mulch GA3 injection (2,000 ppm) also increased yield, mean spear weight, and number of spears more than 20 cm long in the presence of clear plastic mulch (Table 6). The experiment was replicated over two clones of 'Victoria'. No significant clonal differences occurred and data presented are means for the clones. After plastic removal and clean harvest, regrowth was more rapid on GA-treated crowns. However, the yield difference at second harvest was not significant (data not shown). Single vs. Multiple Injection The effect of multiple vs. single injection appeared very striking within the first three weeks following injection of 'Victoria'. Accelerated growth on singly injected crowns occurred only near the injected bud; the multiply injected crowns usually had three distinct sites of rapid growth. However, there were no statistically significant increases in yield components for multiply vs. singly injected crowns. Apparently, any differences that might have occurred were obscured by normal variation, or the injected GA may have slowly diffused to other growing points (yield data not shown). Spray Treatments Some early stimulation of growth by spray application of GA was evident but early differences were not reflected in any yield component (data not shown). Direct injection may be necessary to insure the GA growth response. The high rate spray treatment resulted in application of 50 mg GA/crown compared to 20 mg GA/crown for the high rate injection treatment. Much of the sprayed material was lost as runoff and absorption through the buds was small. Late Spring Injections Application of GA in June after harvest of the first crop had no statistically significant effect on yield and there was no stimulation of early regrowth (data not shown). Table 2. Effect of Gibberellin Injection on Total Yield of Rhubarb, 1982 GA treatment Variety Total spear Mean for GA Mean for variety wt. (kg/crown) treatment (kg/crown) (kg/crown) Control Crimson 4.00 Control 2.86 Crimson 4.26 German Wine 1.58 500 ppm 3.38 German Wine 2.53 Victoria 2.99 2,000 ppm 4.90 Victoria 4.35 ------------------ LSD (0.05) 0.63 500 ppm Crimson 3.79 German Wine 2.17 Victoria 4.19 ----------------- 2,000 ppm Crimson 5.00 German Wine 3.84 Victoria 5.87 Table 3. Effect of Gibberellin Injection on the Number of Spears Harvested per Crown, 1982 GA treatment Variety Total spears/ Mean for GA Mean for crown treatment variety Control Crimson 70 Control 82 Crimson 74 German Wine 67 500 ppm 91 German Wine 90 Victoria 110 2,000 ppm 117 Victoria 127 ------------------ LSD (0.05) 11 500 ppm Crimson 69 German Wine 80 Victoria 124 ------------------ 2,000 ppm Crimson 82 German Wine 124 Victoria 146 Table 4. Effect of Gibberellin Injection on Mean Spear Weight, 1982 GA treatment Variety Mean spear Mean for GA Mean for wt. (g) treatments(g) variety (g) Control Crimson 57 Control 36 Crimson 58 German Wine 24 500 ppm 39 German Wine 27 Victoria 27 2,000 ppm 44 Victoria 34 ----------------- LSD (0.05) 6 500 ppm Crimson 55 German Wine 27 Victoria 34 ----------------- 2,000 ppm Crimson 61 German Wine 31 Victoria 40 Table 5. Effect of Gibberellin Injection on Numbers of Spears/Crown Exceeding 20 cm in Length, 1982 GA treatment Variety Spears/crown Mean for GA Mean for over 20cm treatment variety Control Crimson 28 Control 23 Crimson 32 German Wine 10 500 ppm 35 German Wine 31 Victoria 30 2,000 ppm 57 Victoria 52 ---------------- LSD (0.05) 26 500 ppm Crimson 29 German Wine 29 Victoria 47 ---------------- 2,000 ppm Crimson 38 German Wine 54 Victoria 78 Table 6. Effect of Gibberellin Injection on Yield Parameters of Plastic Mulch Covered 'Victoria' Rhubarb, 1982 GA treatment Total spear Number of spears Mean spear Number of spears/ wt. (kg/crown) harvested/crown weight (g) crown over 20 cm Control 2.44 84 28 11 2,000 ppm 4.01 85 49 36 LSD(0.05) 1.07 NS 11 13 Sweet Corn Response to Lime, Cu, and P Fertilizers Cooperators: T.L. Jackson and D.W. McAndrew, Department of Soil Science, Oregon State University, Corvallis. Sweet corn yields in the Willamette Valley are known to increase with application of lime and banded P fertilizers, even in the presence of a high P soil test. However, the interaction of applied P fertilizers and lime, which increases availability of soil P, has not been explored in detail. Surveys in commercial fields and experiments at the North Willamette Station indicated possible Cu deficiencies in corn leaf tissue. Application of large amounts of P could induce a Cu deficiency by making soil Cu less available. The objectives of the 1981 experiments were to study the effects of 1) combinations of broadcast and banded P at four soil pH levels at two planting dates, 2) broadcast P and Cu in combination with three (banded) P carriers, on yield and nutrient content of sweet corn. The objectives of the 1982 experiments were to study the effects of 1) three rates of banded P fertilizer and Cu with and without application of lime, and 2) four P carriers at two rates of P with and without lime on yield and nutrient content of 'Jubilee' sweet corn. Methods In 1981, Willamette silt loam main plots of 0, 4.5, 9.0, and 13.5 MT/ha of lime (pH 5.6, 6.0, 6.6) were split by a broadcast, incorporated application of 0 and 76 kg P/ha. These subplots were split again by application of 33 or 76 kg P/ha banded 5 cm beneath and 5 cm to the side of the seed line. Plots were seeded on May 11 and a second set on June 3. Monocalcium phosphate was the P carrier for all treatments and all plots received 200 kg N/ha. The second experiment involved a 2x2 factorial combination of broadcast P at 0 or 76 kg/ha and Cu at 0 or 5.5 kg/ha. The Cu x P factorial was split by banded application of urea phosphate (17-44-0; N-P205-K20), diammonium phosphate (18-46-0), or monocalcium phosphate (0-45-0) at 33 or 76 kg P/ha. All plots received a total application of 220 kg N/ha. Planting date was May 27. In 1982, lime was applied at rates of 0 or 6.7 MT/ha. In the first experiment, P was applied at planting on May 5 as a band treatment of 11-51-0 at 33 kg P/ha or 33 kg P/ha as 11-51-0 plus 43 kg P/ha as 0-45-0. Copper at 11 kg/ha was applied before seedbed preparation only in combination with the high rate of P. The lime main plots were split by the four Cu-P treatments in randomized block design. In the second experiment, the lime plots were split by banded P application, at 0, 33, or 76 kg/ha, in the form of 12-51-0 (ammonium polyphosphate), 16-41-0 (urea phosphate), 17-44-0 (urea phosphate), or 18-46-0 (diammonium phosphate). Seeding was done on June 2. All plots received a total of 200 kg N/ha. Results - 1981 In the first experiment, the major yield responses were to lime and P. At the early planting date, mature ear yield and cutoff yield increased with the higher rate of banded P only on unlimed soil. Liming increased yield with the low rate of P, but not at the higher rate of P. At the late planting date, the yield response to P was of greater magnitude than at the earlier planting date. Response to banded or broadcast P was strongest at low soil pH. Leaf tissue P levels generally increased with increasing soil pH and either banded or broadcast P treatment. Leaf copper content decreased with application of lime or P. Leaf Zn and Mn content also decreased with application of lime. In the second experiment, application of Cu increased leaf Cu content but had no effect on ear yield or cutoff yield. Form of applied P (carrier) had no effect on any yield parameter. Results - 1982 In the first experiment, application of lime had no effect on yield of mature ears or total ear yield when averaged over P-Cu treatments, but lime did increase the cutoff ratio (weight of kernels/weight of ears) from 0.46 to 0.49. Copper and P had no effect on any yield parameter when averaged over lime rates. At zero lime application, P increased yields of mature ears by 5 MT/ha and cutoff yield by 3 MT/ha. Application of P had no effect on yield of corn grown on limed soil. In the absence of applied P, lime increased yield of mature ears and cutoff yield. Leaf P concentration increased with P but not lime treatments. Leaf Cu content decreased with P application but was partially restored by application of P+Cu. Leaf Zn content decreased with P or lime application and Mn content decreased with lime application. In the second experiment, the form of P fertilizer (P carrier) had no consistent effect on any yield parameter or on leaf nutrient content. Lime had no significant effect on yield when averaged over P rates and carriers, but did increase mature, total, and cutoff yield, and cutoff ratio in the absence of banded P. Mature ear yield, total yield, and cutoff yield were increased by P application, with yields at 76 kg P/ha higher than yields at 33 kg P/ha. Leaf P content was increased by the high P rate but not by the low P rate. Lime tended to increase P content, but the differences were not statistically significant. Leaf Cu content decreased with P application. Leaf Cu, Mn, and Zn content decreased with lime application. Discussion Maintaining an adequate soil pH near 6.0 and use of P fertilizers are key factors in achieving maximum yields of sweet corn. Earliness, as reflected in yields of mature ears, is greatly promoted by available P. Phosphorus availability can be increased either by banding P fertilizer or by liming, preferably both. However, lime has little effect on yield in the presence of large amounts (175 kg P205/ha) of banded P. The formulation of N-P fertilizers (carrier effect) has little effect on yield. High rates of P reduce leaf Cu content slightly but addition of Cu did not increase yields in these experiments. Apparently, induction of Cu deficiency by high rates of P fertilization should not be a problem in sweet corn production on Willamette soil. Response of Vegetable Crops to Anticrustants Poor stand establishment is often a limiting factor in vegetable production. Soil crusting or high mechanical resistance (MR) to seedling emergence is caused by destruction of soil aggregates and contributes to poor stands on many soils. Small-seeded crops such as carrots, lettuce, onions, and the cabbage family lack the seedling vigor necessary to penetrate a cohesive crust. Crusting may be reduced by frequent light irrigation or shallow cultivation, but these methods may reduce aeration or destroy non-emerged seedlings. These studies, a continuation of a project started in 1980, were designed to compare the effects of several possible anticrustant on crusting of Willamette soil and on the emergence and yield of several small-seeded vegetable crops. Methods - 1981 On April 29, 1981, 'Waldmann's Green' lettuce, 'Scarlet Nantes' carrot, and 'Sentinel' onion were seeded at 30/m and'Marketmore' 76 cucumber at 15/m on Willamette silt loam. The plot area had been prepared by plowing, disc incorporation of 1,120 kg/ha of 10-20-10, and rototilling to form a finely pulverized seedbed. Treatments included 1) a check; 2) phosphoric acid (PA) applied at 56 kg/ha of total area in a 7.5 cm over-the-row band; 3) neutral ammonium phosphate as 10-34 solution (NAP), also in a 7.5 cm over-the-row band at 50 kg P/ha, 4) sulfuric acid (SA), 7.5 cm over-the-row band at 57 kg S/ha, 5) Nalco 2190, a commercial anticrustant, at 240 liters/ha of 10% (v/v) solution, also in a 7.5 cm band; and 6) horticultural grade vermiculite at 1.3 m3/ha. A duplicate set of PA treatments was applied and the stands were later thinned to equal the check plot stands. Treatments were completely randomized with four replications. Irrigation was by overhead sprinkler as needed except that 1.5 cm was applied one day after seeding and plots were not irrigated again for 14 days. Stand counts were made at several intervals after seeding and soil MR was measured 14 days after seeding with a penetrometer. Results and Discussion - 1981 Results were generally consistent with those obtained in 1980. Vermiculite was again the most effective treatment in reducing MR (Table 1). Unlike 1980, Nalco 2190 was second most effect in reducing MR. PA and SA were also effective as anticrustants; NAP reduced crusting slightly (Table 1). Vermiculite was the most effective treatment for hastening the emergence of all crops except cucumber, where treatment effects were confounded by bird damage (Table 2). Final stands of onion were not affected by anticrustants, but emergence was most rapid with vermiculite (Table 2). Although Nalco 2190 was the second most effective treatment in reducing MR at 14 days (Table 1), PA was usually the second most effective material for hastening emergence and produced the second greatest final stands of lettuce and carrot (Table 2). This confirms 1980 results. SA severely retarded emergence of all crops except cucumber and greatly reduced final stands of carrots and lettuce. Nalco 2190 and NAP had little effect on emergence rate or final stands, as in 1980. Yields (sum of two harvests) of cucumbers and onions were not affected by anticrustant treatment (Table 1). Yield of carrots and lettuce varied in proportion to the final stands. Vermiculite produced the highest yields, SA the lowest. Second highest yields of lettuce and carrots were obtained with PA. When stands on the duplicate set of PA plots were thinned to equal control stands, PA treated plots still tended to outyield check plots, indicating that P was being made available to the plants. Nalco 2190 increased yields only of carrots, while NAP had no effect on yield of any crop. Vermiculite was the most effective treatment under these conditions. Covering the band with a thin layer of soil prevented wind or water erosion of the vermiculite, but did not prevent bird damage on cucumber and onion plots. PA remains a good choice as anticrustant, particularly when P availability is limited by low soil P content or low soil temperature. All treatments were cost competitive, ranging from $50 to $75/ha for materials. Table 1. Effect of Anticrustants on Soil Mechanical Resistance 14 Days after Seeding and on Vegetable Yields, 1981 Soil Yield Anticrustant MR Carrot Cucumber Lettuce Onion g.force^Z -----------------MT/ha ------------ Check 810 5 47 7 28 PA 490 13 51 12 34 PA, thinned 490 9 50 9 30 SA 450 2 50 1 20 Nalco 2190 420 10 48 7 28 NAP 560 6 44 6 30 Vermiculite 310 15 55 33 34 LSD(O.05) 80 3 NS 4 7 ^ZForce required (in grams) to penetrate soil to a depth of 1.0 cm with a 2-mm diameter circular probe. Table 2. Effect of Anticrustants on Seedling Stands, 1981 Stand (seedlings/m) 14 days 28 days Anticrustant Carrot Cucumber Lettuce Onion Carrot Cucumber Lettuce Onion Check 4.7 3.3 4.4 4.7 5.7 13.5 5.0 4.0 PA 8.7 9.0 7.0 6.7 8.8 16.0 7.2 4.4 PA, thinned 8.5 8.9 7.0 7.0 5.7 13.0 5.0 4.0 SA 1.0 3.7 0.2 2.2 1.2 15.2 0.3 2.8 Nalco 2190 6.3 5.7 6.0 4.0 7.8 12.7 6.0 3.7 NAP 5.7 5.7 3.4 6.0 6.2 13.6 3.8 2.8 Vermiculite 12.2 8.8 25.3 7.7 12.3 16.5 24.5 4.4 LSD(0.05) 1.8 1.7 1.4 1.8 2.0 NS 2.2 NS Methods - 1982 Nalco 2190 was applied as an over-the-seed row banded spray at the label rate (see above), twice the label rate, and at a tenfold dilution of the label rate but with 10 times the normal total spray volume (flood treatment). Thus, the first and third treatments resulted in the same amount of Nalco 2190 applied per unit area, but with the third treatment there was a tenfold increase in water applied, resulting in a more thorough wetting of the soil surface. Stand counts were made for 'Nantes' carrot and 'Waldmann's Green'lettuce and soil MR was measured. Results - 1982 Soil crusting was reduced by all three treatments as compared to a water-sprayed check, but the three Nalco 2190 treatments did not differ among themselves (Table 3). Stands of carrots at 11 days after seeding were increased 80% to 112% by Nalco 2190; lettuce stands at 15 days were also increased with Nalco 2190. Neither the rate of Nalco 2190 applied nor the volume of water applied affected the stand of either crop. Nalco 2190 was more effective in increasing stands of lettuce and carrots in this trial than in 1980 or 1981. Table 3. Effect of Nalco 2190 on Soil MR and Stands of Carrot and Lettuce, 1982 Nalco 2190 Soil MR, Carrot stand Lettuce stand treatment 10 days 11 days 15 days g.force - - - - - seedlings/m- - - - - Check 660 11.0 5.0 1x spray 540 19.7 7.0 2x spray 475 20.3 6.5 Flood 465 23.3 7.3 LSD(0.05) 170 4.6 1.3 Effects of Soil Acidity and N Fertilizers on Vegetable Stands Previous experiments at the North Willamette Station (1979, 1980) have established that stands of carrot, cauliflower, and lettuce on Willamette silt loam are inhibited at pH less than 5.8 compared to higher pH. In addition, broadcast applications of N fertilizers have reduced stands when compared with unfertilized soil. In the 1979 experiments, ammonium sulfate at 112 kg N/ha depressed stands by approximately 15% to 45%, depending on the crop; at 224 kg N/ha, ammonium sulfate depressed stands by 30% to 55%. On the other hand, calcium nitrate at 112 or 224 kg N/ha did not reduce stands. It was postulated that the effect of ammonium sulfate was caused by lowered soil pH or ammonium-toxicity. In 1980, a wide range of fertilizers was applied at 224 kg N/ha to attempt to separate the salt injury, ammonium-toxicity, and pH altering effects of the fertilizers. As in 1979, raising the soil pH increased stands. However, unlike 1979, all fertilizers except urea depressed initial stands of carrots and lettuce. The effects of calcium nitrate and ammonium sulfate were about equal. Other fertilizers such as potassium nitrate, ammonium nitrate, and potassium chloride also reduced stands. These fertilizers represent a broad range of soil acidifying potential and salt injury potential. Urea, at 224 kg N/ha, had a lower salt damage potential than the other fertilizers. In 1981 and 1982, the experiments were designed to shed further light on the stand depressing effects of various N sources and to determine whether incorporation of the fertilizer into the soil would reduce fertilizer effects on stand. Methods In 1981, cultivars used were 'Salad Bowl' lettuce and 'Scarlet Nantes' carrot. Main plots [four levels of soil pH, (Table 1)] were in randomized block design, split by three methods of fertilizer application, and these subplots split by application of calcium nitrate, ammonium sulfate or potassium nitrate at 112 kg N/ha and an unfertilized check. Each treatment combination was replicated four times. The application methods were 1) broadcast entire amount before planting, 2) band half the fertilizer (5 cm to the side, 5 cm below the seed row) at planting, broadcast remainder before planting, and 3) band half the fertilizer at planting, broadcast remainder before planting and incorporate into top 5 to 8 cm of soil. All plots were seeded at 30 seeds/m. Stand counts were made 10 days after seeding. In 1982, treatments were in split-plot factorial design with pH of 5.6, 5.9, 6.2, and 6.6 as main plots, broadcast vs. broadcast and incorporated fertilizer as subplots, and broadcast application of the following fertilizers at 168 kg/ha as sub-subplots: ammonium sulfate, ammonium nitrate, calcium nitrate, nitroform, and unfertilized check. Plots were seeded to 'Salad Bowl' lettuce. Stand counts were made one week after seeding. Results In 1981, as in previous years, increasing the soil pH from 5.0 to 6.0 tended to increase stands, but the difference was statistically significant only for lettuce (Table 1). For both lettuce (Table 1) and carrots (Table 2), incorporating the broadcast portion of the fertilizer into the soil clearly prevented the stand-reducing effects of fertilizer application. All fertilizers tended to reduce stands of both crops. Stand reduction was most severe with calcium nitrate. This is in contrast to results in 1979, when calcium nitrate did not depress stands, and also contrasts with results in 1980 when calcium nitrate depressed stands, but no more than ammonium sulfate or potassium nitrate did. In contrast to 1979, but in agreement with 1980, there was no trend for a significant pH x fertilizer material interaction: raising soil pH did not ameliorate stand reduction effects of one fertilizer more than another fertilizer. There was a significant interaction of application method and fertilizer material in the case of carrots (Table 3). When fertilizer was broadcast or banded and broadcast, fertilizers significantly reduced stands when compared with unfertilized plots. However, when the broadcast portion was incorporated into the soil, fertilizers did not significantly reduce stands. Table 1. Main Effects of Soil Acidity, Method of Fertilizer Application, and Type of Fertilizer on Seedling Stands of Lettuce, 1981 Soil Lettuce stand Application Lettuce stand Fertilizer Lettuce stand pH (seedlings/m) method (seedlings/m) material (seedlings/m) 5.1 5.5 Broadcast 6.5 None 16.5 5.7 8.5 Band and broadcast 7.0 Ammonium sulfate 9.5 6.2 19.0 Band and incorporate 19.5 Calcium nitrate 5.8 6.6 10.8 LSD (0.05) 4.1 Potassium nitrate 12.0 LSD (0.05) 3.3 LSD(0.05) 5.0 Table 2. Main Effects of Soil Acidity, Method of Fertilizer Application, and Type of Fertilizer on Seedling Stands of Carrots, 1981 Soil Carrot stand Application Carrot stand Fertilizer Carrot stand pH (seedlings/m) method (seedlings/m) material (seedlings/m) 5.1 11.0 Broadcast 9.5 None 14.5 5.7 9.8 Band and broadcast 9.5 Ammonium sulfate 11.3 6.2 12.3 Band and incorporate 15.3 Calcium nitrate 10.8 6.6 12.8 LSD (0.05) 3.6 Potassium nitrate 9.5 LSD(0.05) NS LSD(0.05) 2.1 Table 3. Interaction of Fertilizer Application Method and Fertilizer Material on Seedling Stands^Z of Carrots, 1981 ____________________________________________________________________ Application Fertilizer material method None Ammonium Calcium Potassium sulfate nitrate nitrate -----------------seedlings/m ---------------- Broadcast 12.8 10.0 8.3 6.8 Band and broadcast 14.3 7.8 10.5 6.8 Band and incorporate 16.3 15.5 14.5 14.8 ^ZAveraged over four levels of soil pH. LSD(0.05) = 2.8. In 1982, the effect of soil pH on lettuce stand was highly significant (Table 4). A soil pH of 6.2 produced the best stands and there were no significant pH x fertilizer or pH x application method interactions. Stands were reduced slightly at pH 6.6 and were lowest at pH 5.6. Incorporation of fertilizer tended to increase stands, but the increase was not significant. Form of fertilizer did not have a significant effect in this trial. The most useful general conclusion that can be drawn from the four years of this study is that for best stands, soil pH should be near 6.0, pre-emergence fertilizer applications should be moderate, and broadcast fertilizers should be soil incorporated. Table 4. Main Effects of Soil Acidity and Fertilizer Application Method on Lettuce Stands, 1982 Soil Lettuce stand Application Lettuce stand pH (seedlings/m) method (seedlings/m) 5.6 5.1 Broadcast 8.3 5.9 9.1 Incorporated 10.1 6.2 12.8 LSD(0.05) 1.5 6.6 10.4 LSD(0.05) 1.5 Sewage Sludge as a Sweet Corn Fertilizer Cooperators: T. L. Jackson and V. V. Volk, Department of Soil Science, Oregon State University, Corvallis. Sewage sludge has been used as an effective source of plant nutrients for sweet corn in several short-term studies. However, the long-term effects of sewage sludge on sweet corn yields and soil chemistry have not been widely investigated. Previous results at the North Willamette Station indicated that two to three years cumulative applications of sludge were necessary before yields on sludge-treated soils equalled those on soils treated with optimal rates of commercial N fertilizers. Also, the yield response of sweet corn to banded P fertilizer could not be duplicated with sewage sludge. The experiment described below was intended to measure sweet corn yields after seven consecutive years of application of three Willamette Valley sewage sludges. Several rates of commercial N were also applied, both with and without banded P fertilizer. Methods The seventh annual sewage sludge treatment was applied on April 22, 1982, and plowed under within 48 hours. Sludges from the City of Portland, City of Salem, and the Unified Sewerage Agency (Rock Creek) were applied at rates approximately equivalent to 200 and 400 kg/ha of total N. In addition, the high rates of sludge were applied to plots which had been treated with lime at 13.5 MT/ha in 1976. Commercial N as ammonium sulfate was banded at planting at a rate of 56 kg N/ha. Appropriate plots were sidedressed with ammonium nitrate six weeks after seeding. Banded P was applied to appropriate plots as concentrated superphosphate banded at planting. 'Jubilee' sweet corn was seeded on May 21, 1982. Stands four weeks after planting averaged 60,000/ha. Between row spacing was 0.75 m. Plot size was 4.5 m x 9.0 m with four replications of each treatment in randomized complete block design. Yield records were taken from the centermost two rows of each plot. Ears were harvested on September 2 and graded as mature, slightly immature, or culls. Culls were not included in yield figures. Samples of kernels were taken for nutrient and trace metal analysis (data analysis not completed). Only soil pH and yield data are presented here. In addition to the sludge and commercial N treatments, several plots of uniform N rate were split by application of different rates of banded P. Results and Discussion Yields of mature ears increased with commercial N application to a maximum at 168 kg N/ha in the presence of banded P (Table 1). In the absence of banded P, mature ear yields also increased with N, with a maximum at 224 kg N/ha. Mature ear yields were always higher with banded P than at the same N rate without banded P; however, the differences were not usually statistically significant. Total ear yields responded similarly to increasing rates of N, with highest yields at 168 or 224 kg N/ha. Total ear yields in the presence of banded P did not generally exceed those obtained without banded P. Thus, the major effect of banded P was to hasten maturity. Trends in mean ear weight were similar to those for yields, but were not statistically significant. Most of the yield increases at higher rates were caused by a greater number of ears harvested rather than increased ear weight. Yields on sewage sludge amended soil were approximately equal for the two rates of sludge applied and were about equal to the yields with the optimal rates of commercial N fertilizer. Apparently, cumulative applications of the low rates of sludge provided ample N for optimal sweet corn yields at this planting density. Yields did not vary significantly with the source of sludge. As with the commercial N fertilizer, banded P fertilizer significantly increased mature ear yield on plots treated with the low rate of Portland sludge. Yields on soils treated with lime and sludge tended to be higher than those on soils treated only with sludge and tended to be higher than with optimal rates of commercial N fertilizer. Seven years cumulative application of sludge or commercial N reduced soil pH by up to 0.6 units when compared to unfertilized soil (Table 1). The low pH (5.2 to 5.5) on plots repeatedly fertilized with sludge or higher rates of commercial N may be limiting yields on these plots. Soil pH on the limed plots was nearly 1.0 pH unit higher than on unfertilized plots in 1977. In 1982, the limed and sludge treated plots had the same average pH as unfertilized plots. Apparently, the continued application of acid-forming N fertilizer and sludge mineralization has produced a significant increase in soil acidity (lowering of pH). This may have an impact on uptake of toxic heavy metals from sludge or fertilizer-amended soils. Several plots previously treated with either chicken manure or sewage sludge were treated with several rates of banded P fertilizer in the presence or absence of starter N in the band (Table 2). Inclusion of N in the band generally had no effect on yield unless was also present. The effect of banded P was usually significant. In most cases higher mature ear yields were obtained on the subplot receiving the higher rate of banded P. Mean ear weight was not significantly affected by banded P treatment. Sewage sludge is an effective N source for sweet corn and commercial N fertilizer is not necessary for optimal yields. However, P should still be applied in a band at planting. Careful management of soil pH will be necessary to maintain high yield and avoid heavy metal uptake. Table 1. Soil pH and Yield of Sweet Corn on Sewage Sludge-amended Soil Commercial Banded P Nominal sludge Soil Mature Total Mean ear wt. N applied applied total N applied pH ear yield ear yield of all ears (kg/ha) (kg/ha) (kg/ha) (MT/ha) (MT/ha) (kg) 0 0 0 5.8 9.2 11.9 0.28 112 0 0 - 16.2 18.9 0.30 168 0 0 - 14.9 19.8 0.2