Soil Organic Matter and Tomato Yield following Tillage, Cover Cropping, and Nitrogen Fertilization

Management practices can influence soil C and N and tomato ( Lycopersicon esculentum Mill) yield. We examined the influence of tillage practices [no‐till (NT), chisel plowing (CP), and moldboard plowing (MP)], cover crops [hairy vetch ( Vicia villosa Roth) vs. winter weeds], and N fertilization rates (0, 90, and 180 kg N ha −1 ) on soil organic C and N, potential C and N mineralization (PCM and PNM, respectively), inorganic N contents, and tomato yield and N uptake. A 3‐yr experiment was conducted on a Dothan sandy loam (fine‐loamy, siliceous, thermic, Plinthic Paleudults) in central Georgia. Soil organic C and N after 3 yr were greater in NT with vetch than in CP and MP with vetch or weeds at 0‐ to 20‐cm depth. The PCM, PNM, and inorganic N were greater in MP than in NT and CP at 7.5 to 20 cm in May 1996 but were greater in NT and CP than in MP at 0 to 7.5 cm in April 1997. At 0 to 20 cm, PNM and inorganic N were also greater with vetch than with weeds in April 1996 and 1997 and with 180 than with 0 kg N ha −1 in May 1996 and August 1997. Tomato yield and N uptake were greater in CP and MP than in NT and with 90 and 180 kg N ha −1 than with 0 kg N ha −1 . Although NT with vetch can improve soil organic matter, CP can sustain tomato yield compared with MP, thereby reducing the potential for soil erosion. Hairy vetch can increase labile soil N pool and 90 compared with 180 kg N ha −1 can sustain tomato yield, thereby reducing the amount of N fertilizer and potential for N leaching.