Influence of Different Soil Moisture Regimes on Biomass Production, Water Use, and Nitrogen Nutrition of Tomato Plants.

Abstract

In a pot experiment under controlled condition, tomato (Lycopersicum esculentum Mill.) plants were grown for 28 days under five different soil moisture regimes (SMRs), viz. non-irrigated, and irrigated up to container capacity (CC) level allowing 60, 45, 30, and 15% depletion of CC moisture (DCCM) . The plants showed a higher weekly average evapotranspiration (ET) rate, and a higher cumulative ET after 28 days after transplanting (DAT) when more water was made available in their root zone through irrigation. Biomass production in different plant parts and water use efficiency increased significantly with frequent irrigations allowing minimum soil drying from CC level. High sensitivity of the crop to soil moisture stress was indicated by a significant reduction in biomass production when irrigations were given allowing more than 15% DCCM. Nitrogen dilution effects in different plant parts were observed for the wetter SMRs. However, total N uptake was remarkably enhanced with increased availability of soil moisture. Significant and positive correlations of biomass production with water use and N uptake were noted. A soil moisture regime that allows up to 15% DCCM for irrigation performed best with regard to biomass production and nitrogen uptake as well as agronomic efficiencies of water and nitrogen. The findings merit considerable significance to irrigation scheduling and water management for maximizing tomato yields.