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Roland Roberts, David Bender and Samuel Field

Extension-research teamwork supports Texas High Plains onion grower-shippers in transition from unprofitable labor intensive marketing and culture to profitable mechanical systems that are less stressful to workers. System comparisons include machine harvest vs. lifting and hand clipping; stationary seed grading and bagging vs. mobile field grading and bagging; transplant vs. fall seeding, spring seeding and dry set production. Old marketing systems cost growers $4.30/50-lb. sack, and the innovative system costs $2.59 to $3.00/sack. Old transplant systems average $450 to $500/acre and direct seeding costs $200/acre. Net increase in return to grower management from adoption of new systems range from $1,300 to $1,700. Extension and research conduct economic analysis, cultivar performance trials, seeding technique studies and on-farm demonstrations.

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Roland E. Roberts and Michael G. Hickey

Texas processing potato growers want high tuber yield and soluble solids with optimal nitrogen (N) fertilization to avoid leaching N into underground water. A 3-year on-farm study demonstrated petiole and soil testing methods for N enabling growers to apply N at rates and times for maximum yield with acceptable specific gravity. For example, a FL-1553 crop received 160 N kg/ha in irrigation water spread over 126-day season. Sampling every 2 weeks from early vegetative stage to harvest showed petiole N of 22,000 ppm on day 40; 6,000 ppm on day 54; 3,000 ppm on day 68; 7,000 ppm on day 96; and 2,000 ppm by day 110. At harvest total tuber N = 1.12%; tuber specific gravity = 1.081 (17.1 % FritoLay solids); and processor acceptable yield = 304 q/ha. The crop removed nearly all applied N.

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Greta Schuster, Roland E. Roberts and David Bender

Rhizoctonia solani infection of potato causes seed piece decay and stem and tuber lesions, resulting in delayed emergence and uneven stands, low-vigor plants and unmarketable tubers. Rhizoctonia prevention effectiveness of three fungicide/fir bark dusts and nontreated tubers were compared on three varieties. Seedpieces of Viking, Atlantic and Norkotah 278 were treated and planted in separate commercial fields. A randomized complete-block design with four replications with four 26-foot rows per treatment plot included four treatments: 0.5 lb Maxim, 1.0 lb Tops MZ, and 1.5 lb Nubark Captan dust/100 lb seed. Plant stems, stolons and tubers were examined for Rhizoctonia infection at the tuber initiation stage and tubers were examined again at mature stage. Maxim and Tops MZ reduced stolon infection in Atlantic and Norkotah 278 and reduced stem infection in Norkotah 278. Plants from Maxim treated tubers produced more stems/plant in Norkotah 278 and produced more weight of tubers weighing less than four oz in all three varieties. Differences in seed tuber conditioning and mechanical damage in seed handling increase variability of treatment effects. Repeated testing of potato seed piece treatments in Texas High Plains conditions is the best way to confirm potential of beneficial effects of seed treatment.

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David A. Bender, Roland E. Roberts and Frank J. Dainello

Watermelon is grown under a range of moisture regimes from rainfed to heavily irrigated, but water requirement patterns are not well documented. Drip irrigation and plastic mulch provide the opportunity to control water applications to optimize yield and quality. Water applied through subsurface drip irrigation was measured in two watermelon trials in 1998 (25 seeded and 20 seedless cultivars) and 1999 (26 seeded and 14 seedless cultivars) at Lubbock, Texas. Melons were transplanted in plastic-covered raised beds 13.6 m long spaced 2 m apart. Irrigation was applied when morning soil moisture tension measured by tensiometers exceeded 20 kPa. Watermelon yields ranged from 50 to 100 t·ha-1 with excellent quality. Weekly water use averaged 14 mm during the first 3 weeks of establishment then increased to 28 mm during the next 3 weeks as plants were running and blooming. During the 5-week fruit-enlargement period, water uptake averaged 57 mm, then decreased as full fruit size was attained. Similar uptake patterns in both years suggest that meaningful crop coefficients for scheduling watermelon irrigation could be based on phenological growth stages.

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David A. Bender, J. Wayne Keeling and Roland E. Roberts

Large weeds, particularly amaranths, are a serious impediment to mechanical harvesting of jalapeno peppers. Several herbicides were applied in 1998 and 1999 postemergence topical (PT) to commercial fields when peppers had four to six leaves, or postdirected (PD) with a shielded sprayer ≈1 month later, and evaluated for crop injury, weed control, and effects on yield. Treatments were applied to four-row plots 9 m long with a CO<subscript>2 backpack sprayer. PT treatments included pyrithiobac sodium at 0.036, 0.053, or 0.071 kg·ha–1 a.i. with nonionic surfactant or crop oil concentrate, metolachlor at 1.68 kg·ha–1 a.i., and oxyfluorfen at 0.14 or 0.28 kg·ha–1 a.i.. PD treatments consisted of the same rates of pyrithiobac sodium with nonionic surfactant only, and the same rates of oxyfluorfen. Pyrithiobac sodium PT caused significant chlorosis (reduction in SPAD chlorophyll) in new foliage and reduction in plant height after 1 week, but plants recovered with no effect on final plant height, chlorophyll, or yield. No significant difference was observed between the two adjuvants. Metolachlor had no measurable effect on pepper growth or yield. Oxyfluorfen PT killed young apical tissue and caused chlorosis of immature leaves. Plants recovered, but plant height was reduced by 14% to 28% and yield by 11% to 43%. PD treatments had no effect on pepper growth or yield. All herbicides provided adequate weed control under light pressure. Pyrithiobac sodium appears to have potential as a postemergence herbicide for control of amaranth in jalapeno peppers.

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Roland E. Roberts, David A. Bender, Jackie Smith and Stanley Young

A market window for onion occurs when f.o.b. prices are above grower break-even price for a period of 4 to 6 weeks. Market windows were calculated to occur from late June to early August and from early October through December for northwest Texas onions. Five-year average prices ranged from $6.25 to $7.40 (1990–94), and a breakeven price of $5.38/50-lb sack was calculated from an analysis of total costs of production and marketing and historic yields. Ongoing research and grower demonstrations with advanced breeding lines, commercial cultivars, and selections from yellow, white, and red cultivars have defined certain cultivars that display superior attributes and mature within the market window. Superior cultivars adapted to the first market window include XPH-87N60, `Sunre 1445', `Sunre 1462', `Yula', `Spano', `Cimarron', `Riviera', `Utopia', and `Alabaster'. Superior cultivars adapted to the second market window include `Sweet Perfection', `Sterling', `Vega', `Bravo', `Capri', `Vaquero', `El Charro', `Quest', `Shasta', and `Vision'. `Vaquero', `Sunre 1462', `Sunre 1445', `El Charro', and `Viceroy' have potential for short-term storage for October to December markets.

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Roland E. Roberts, Kenneth Gray and Joseph J. Bryant

Breedlove Dehydrated Foods (BDF), the largest charitable dehydration plant in the world, is capable of dehydrating 6,000 lb. raw product/hr. BDF dehydrates and distributes nutritious fruits, vegetables, and legumes to charitable organizations which feed hungry people. At least 35,617 people die from hunger in our world every day! Thousands of tons of nutritious but slightly imperfect horticultural products are wasted yearly in the United States. Donations totaling $7.8 million funded construction of BDF. Texas A&M and Texas Tech Universities provided expertise to plan and operate BDF. BDF dehydrated over 30 million lb. of fruits and vegetables in the initial two years of operation. BDF is a model of people focused on an unusually high goal and working together.

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Robert Pendergrass, Roland K. Roberts, Dennis E. Deyton and Carl E. Sams

Using soybean oil to control insect pests, delay bloom, and thin fruit in peach [Prunus persica (L.) Batsch] production could reduce yield losses and fruit thinning costs compared to the current practice of using petroleum oil spray to control insect pests alone. The higher annua cost of soybean oil spray compared to petroleum oil spray was more than offset by higher average annual revenue from increased peach yields and lower thinning costs. At one location, soybean oil to delay bloom and thin fruit unambiguously reduced production risk. At another location, both mean and variance of returns were higher, but a lower coefficient of variation suggested lower relative risk for the soybean oil spray alternative. Risk resulting from the unanticipated influence of weather and mismanagement on the effectiveness of soybean oil spray were not considered in this analysis. More research is needed to hone in on the optimum soybean oil spray rates under alternative environmental and management conditions.