Influence of Maize Rotations on the Yield of Soybean Grown in Meloidogyne incognita Infested Soil.

A replicated field study was conducted from 1972 to 1980 involving soybeans grown in 2-, 3-, and 4-year rotations with maize in soil infested with Meloidogyne incognita. Monocultured soybeans were maintained as controls. Cropping regimes involved root-knot nematode susceptible and resistant soybean cultivars and soybeans treated and not treated with nematicides. Yields of susceptible cultivars declined with reduced length of rotation. Nematicide treatment significantly increased yields of susceptible cultivars when monocultured, but bad little influence on yield when susceptible cultivars were grown in rotation. Yields of monocultured resistant cultivars were significantly lower than yields of resistant cultivars grown in rotation. However, yields of resistant cultivars grown in rotation were not influenced by the length of the rotation. Nematicide treatment significantly increased yields of monocultured resistant cultivars over the latter years of the study.