Fresh-market Tomato Gas Exchange, Biomass, and Fruit Yield are Similar with Legume Cover Crops or Synthetic Nitrogen Fertilizer

Abstract

Conventional production of tomatoes (Lycopersicon esculentum Mill.) requires substantial investments, intensive management and high inputs of nitrogen. High N rates invariably leave residual soil NO3-N with the potential of polluting ground water and posing health hazard to humans and animals. The objective of this study was to examine the value of cover crops as a substitute to synthetic N fertilizer in growing of tomatoes. The experimental treatments consisted of control (no N fertilizer or cover crop), Abruzzi rye (Secale cereale L), hairy vetch (Vicia villosa Roth), or crimson clover (Trifolium incarnatum L.) cover crop, and fertilization of N at 90 or 180 kg·ha-1. The treatments were replicated four times over 2 years in a randomized complete block experiment for growing `Mountain Pride' tomato on a Greenville fine sandy loam soil. The parameters used to evaluate the performance of tomato consisted of leaf area index (LAI), gas exchange (GE), above ground plant dry weight, number of fruits, dry weight of fruits, and marketable fruit yield. Tomato LAI was similar under legumes and N fertilizers. Hairy vetch and applied N at 90 kg·ha-1 influenced net photosynthesis (Pn) and transpiration (E) the most in both years at all stages of growth. Highest number of tomatoes were produced in hairy vetch and applied N at 90 kg·ha-1 plots. There was no significant difference in the above ground plant dry weight, fruit yield and dry weight of fruits between legumes and N fertilizers. The results suggested that the legume cover crops compared favorably to N fertilizers in promoting tomato growth and development and may have potential of substituting N fertilizers in fresh-market tomato production.