Fall-planted cover crops of hairy vetch (Vicia villosa Roth), Austrian winter pea (Pisum sativum subsp. arvense L. Poir), and crimson clover (Trifolium incarnatum L.) were each followed by spring-planted 'Sundance' summer squash [Cucurbita pepo var. melopepo (L.) Alef.] and 'Dasher' cucumber (Cucumis sativus L.). Squash and cucumber crops were followed by fall 'Florida Broadleaf mustard green [Brassica juncea (L.) Czerniak] and 'Vates' collard (Brassica oleracea L. Acephala group), respectively. The same vegetable sequences were also planted without benefit of cover crop. Three nitrogen (N) rates were applied to each vegetable crop. Squash following winter pea and crimson clover produced greater yields than did squash planted without preceding cover crop. Cucumber following crimson clover produced the greatest yields. No cover crop effect was noted with mustard or collard. Elimination of N fertilizer resulted in reduced yields for all crops, but yields of crops with one-half the recommended N applied were generally comparable to those receiving the full recommended rate.
Owusu A. Bandele, Marion Javius, Byron Belvitt and Oscar Udoh
Heather A. Hatt Graham, Dennis R. Decoteau and Dale E. Linvill
A polyethylene mulch system that changes its predominant surface color from black to white in the field has been developed and used to grow tomatoes (Lycopersicon esculentum Mill. cv. Mountain Pride) and squash [Cucurbita pepo var. melopepo (L.) Alef. cv. Dixie Hybrid]. The system uses a black photodegradable polyethylene mulch placed on top of a white nondegradable polyethylene mulch (photodegradable mulch overlay system). As the black photodegradable mulch degrades with increasing exposure to radiation, the white mulch surface is exposed. Differences among plastic systems in the percentage that breaks down may be explained by differential shading of the mulch by the vegetative growth of the crops. None of the formulations of the Plastigone brand photodegradable mulches in the photodegradable mulch overlay system had an effect on tomato or squash production. As the color of the system changed from black to white, soil temperatures under the mulch decreased. Tomato production remained unaffected in one of the two years as long as the mulch remained black for at least the first 20 days during that season. In year 2, the controlled mulch system color change affected neither tomato nor squash production relative to nondegradable white and black mulches used as controls.
James E. Ells, Ann E. McSay and E.G. Kruse
Irrigation scheduling programs were developed for cabbage and zucchini squash that produced high yield and water-use efficiency with a minimum number of irrigations. The irrigation programs are based on a soil water balance model developed by the USDA. The procedure involved selecting irrigation programs developed for similar crops and using them as standards for cabbage and zucchini for three growing seasons. The treatments involved irrigation levels higher and lower than the standard. After the third year, the best treatment for each year was selected. Coefficients for the standard model then were adjusted by trial and error to produce a program that called for the same number of irrigations and the same amount of water as the best-performing treatment when using the same weather data. These revised programs for cabbage and zucchini squash are available on computer disks and may be used on any IBM compatible PC provided wind, temperature, solar radiation, humidity, and precipitation data are available,