Intercropping Studies With Soybean (Glycine Max (L.); Merr.) and Maize (Zea Mays L.) or Ryegrass (Lolium Perenne L.)

112 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1987.This research concentrates on the study of N fertilizer, N$\sb2$-fixation, and N-transfer under monocrop and intercrop conditions and on the amount of residual soil N after intercrop and monocrop systems. In the experiments reported here, soybean (Glycine max (L.) Merr.) was grown in association with maize (Zea mays L.) under field conditions and with ryegrass (Lolium perenne L.) under greenhouse conditions. A series of six experiments were performed. Two in the field and four in the greenhouse. The intercrop pattern in the field was two rows of soybean per row of maize. Maize plant populations were 30,000 plants/ha and soybean populations were 250,000 plants/ha.In 1984 the LER value was 1.67 when no N fertilizer was applied compared to 1.28 with the application of 150 Kg N/ha. Intercropping soybean with tall maize resulted in a higher LER (1.63) than intercropping with short maize (1.32). In 1985, soybean isolines were the only factors that had an effect on LER values. The LER value was higher (1.12) with nodulating soybean than with nonnodulating (0.91).There was no evidence of nitrogen transfer from soybean to maize under field conditions six days before anthesis, 50 after anthesis or at maturity. However under greenhouse conditions there was evidence of nitrogen transfer from soybean to ryegrass when Chippewas was used but not when Clark was used as the soybean component.N$\sb2$-fixation at the R-2 stage of soybean development was not affected by any experimental factor. At the R-5 stage nitrogen fixation was not affected when soybean was grown under intercrop or monocrop conditions or when it was intercropped with tall or short maize. On the other hand it was reduced 60% when soybean was fertilized with 150 Kg N/ha.In 1984 under field conditions residual soil nitrogen was higher after monocrop soybean than after intercrop soybean-maize and lowest after monocrop maize. In 1985 there was no difference in the amount of residual soil nitrogen among monocrop soybean, intercrop soybean-maize and monocrop maize.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD