Abstract
A field experiment to compare the effects of four summer cover crops and three chemical fumigants on the growth and fruit production of a subsequent winter crop of tomatoes (Lycopersicon esculentum) was conducted at the Tropical Research and Education Center, Homestead, Florida. The cover crops were sorghum sudangrass (Sorghum bicolor × S. Sudanese (Piper) Stapf), sunn hemp (Crotalaria juncea L., cv. 'Tropic Sun'), cowpea (Vigna unguiculata L. Walp, cv. 'Iron clay') and velvetbean (Mucuna pruriens var. utilis (Bort) Merr.). The chemical fumigants were methyl bromide, methyl iodide and metam potassium (KPAM). The cover crops were seeded in June 2002, and incorporated into the soil in October. The soil fumigants were applied three weeks before tomato seedlings were transplanted. The biomass produced by sunn hemp, velvetbean, cowpea and sorghum sudangrass was 19.7, 10.0, 5.0 and 3.3 Mt/ha, respectively. In comparison to the fallow treatment, the sunn hemp treatment significantly (p = 0.05) increased tomato biomass at flowering and fruit yields at early harvest (e.g., harvest 2). The first harvests from sunn hemp and organic mulch treatments produced the largest quantity of tomato fruit. The various fumigant treatments did not affect yield significantly since root-knot nematode populations were negligible. Nematode-antagonistic leguminous summer cover crops are of interest with respect to improving the fertility and other properties of Krome very gravelly loam, and for combating plant parasitic nematode-soil-borne fungal disease complexes.
