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Intercropping of a short-cycle legume crop and a longer-cycle non-legume crop has been suggested as a potentially beneficial intercrop combination. Most studies have concerned cereal and legume corps. Few have involved horticultural crops. In 1990 and 1991, a 56-day semi-leafless pea crop (Curly) and a 75-day lettuce crop (Paris Island Cos) were grown both as monocrops and as intercrops. Intercrops consisting of alternating rows of each crop, represented additive populations (56:100) of peas and lettuce. Three lettuce transplanting dates (June 19, 25 and July 4) and three nitrogen fertilizer rates (0, 50, 100 kg ha$ sp{-1}$) were tested. Peas were all sown on May 18. In addition, a new pea/lettuce intercropping pattern (45:82), consisting of alternating double rows of peas and lettuce, was tested in 1991. The $ sp{15}$N dilution method was also used to test for nitrogen transfer. Alternate row intercropped lettuce plant$ sp{-1}$ yields were, on average, 76% and 46% lower than their corresponding monocrop yields for the early and late transplanted lettuce, respectively. Declines in yield of 63% and 55% were reported for the double row intercropped lettuce for the early and late transplanting dates, respectively. Nitrogen fertilization significantly improved intercropped fresh lettuce yields but had no effect on monocropped lettuce. Pea yields m$ sp{-1}$ row were unaffected by intercropping. Alternate row land equivalent ratios (LER) ranged from 0.87 to 1.05 and from 1.06 to 1.63, in 1990 and 1991, respectively. The double row LER's ranged from 1.06 to 1.21 in 1991. The higher LER's in 1991 reflected higher pea yields. No evidence of nitrogen transfer to the lettuce crop was detected.

An experiment was undertaken to determine the effect of tillage and fertilizer on silage and grain corn production and on soil properties as well as to develop a crop yield model. Conventional, reduced, and zero tillage treatments in combination with inorganic or organic (cattle dairy manure) fertilizer treatments were applied yearly on a clay and a sandy loam soil from 1982 to 1986. The best yields were obtained for the combination of zero or reduced-till and inorganic fertilizers. Zero-till resulted in increased soil density and soil water content and a slight accumulation of P and K in the surface layer of the clay soil. Manure improved soil physical properties especially when combined with zero-till, but resulted in lower N availability to the plants. The factors that limited plant yield in the clay site were plant population, soil nitrate content, bulk density and soil water content. Plant population was the only limiting factor in the sandy loam site. A simplified method for predicting corn yields under different management practices was developed.

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