Influence of N inhibitors on nitrate nitrogen & yield of tomato under intensive cultivation

Abstract

Agricultural soils are responsible for formation of N2O through nitrification and denitrification processes. Nitrification inhibitors reduces the rate at which ammonium is converted to nitrate either by killing or interfering with the metabolism of nitrifying bacteria. Synthetic nitrification inhibitors can efficiently inhibit nitrification. The present study was undertaken to observe the effect of Potassium thiosulfate (PTS) and neem coated urea on N2O efflux under irrigated tomato cultivation to assess its suitability for decreasing N2O emission to the atmosphere. The results depicted the reduction of nitrate nitrogen on third day after fertilizer application compared to zeroth day. The decreased NO3-N was mainly due to the uptake by tomato for its growth and converted into N2O as intermediate product during nitrification process. The yield of tomato (fruit yield) was significantly increased due to the application of various doses and types of N fertilizer application along with N inhibitors. The highest yield (63.2 t ha-1) was recorded with the soil application of nutrients in STCR based recommendation of NPK with Neem coated urea which was on par with the STCR based recommendation of NPK with Normal urea (183:160:125kg ha-1) along with Potassium thiosulfates @ 1% of applied N whereas blanket recommendation of NPK application recorded lower yield. The 38% lowest N2O emission was found in the STCR based recommendation of NPK with Normal urea with Potassium thiosulfates @ 1% of applied N compared to Blanket recommendation of NPK with Normal urea, which was on par with the treatment of STCR based recommendation of NPK with Neem coated urea.