Comparison of the effects of cover crops and nitrogen fertilization on tomato yield, root growth, and soil properties

Abstract

Cover crops can influence soil properties, fruit yield, and growth of above and belowground biomass of tomato ( Lycopersicon esculentum Mill.). The influence of legume [hairy vetch ( Vicia villosa Roth) and crimson clover ( Trifolium incarnatum L.)] and non-legume [rye ( Secale cereale L.)] cover crops and N fertilization (0, 90, and 180 kg N ha −1) was examined and compared on tomato yield, root growth, and soil N and C concentrations. We measured fresh market yield, biomass (dry weight of fruits, stems, and leaves), N uptake, root growth by using the minirhizotron method, and soil inorganic N, organic N, and organic C concentrations on a Greenville fine sandy loam (fine-loamy, kaolinitic, thermic, Rhodic Kandiudults) in 1996 and 1997 in Fort Valley, GA. Tomato fruit yield, biomass, and N uptake were greater with hairy vetch, crimson clover, and 90 and 180 kg N ha −1 than with rye or 0 kg N ha −1. Number of tomato roots per square centimeter of soil profile area (NR) increased from 1 to 26.0 cm depth and then decreased. Total NR from 1 to 32.5 cm depth (TNR) was greater with hairy vetch, crimson clover, and 90 kg N ha −1 than with 0 kg N ha −1. Soil inorganic N at 48 days after transplanting (DAT) in 1996 and at 36 DAT in 1997 were greater with hairy vetch and 90 and 180 kg N ha −1 than with 0 kg N ha −1. In contrast, organic N and C were greater with rye than with 0 kg N ha −1. Because of their higher N concentration, hairy vetch and crimson clover, supplied more N and gave tomato yield and root growth similar to those produced by 90 and 180 kg N ha −1 but higher than that produced by 0 kg N ha −1. Rye increased tomato root growth relative to 0 kg N ha −1 due to higher biomass yield and soil organic C and N levels.