Simulated and Measured Nitrogen Conditions in Tomato Culture

Abstract

Nitrogen (N) loss by nitrate leaching below the root zone may be great in N‐fertilized and irrigated vegetable soils when root uptake does not deplete the mineral N content of the soil water, which percolates through the soil profile. Soil texture and root growth as well as the dynamics of mineral N concentrations in soil solution are major factors in these processes. Differences of nitrate transport in high productive tomato cultures were studied in different texture soils in an irrigated and fertilized lysimeter experiment. In soil 0–60 cm deep, hydraulic properties were determined and nitrate (NO3)‐N and ammonium (NH4)‐N contents were measured in the beginning and end of the experiment. The soil moisture content was monitored in the 0‐ to 60‐cm soil. Root distribution, the dynamics of shoot biomass, N content, leaf area, and fruit yield were also measured. Interactions of root activity and water and N dynamics were evaluated by fitting the SOIL and SOILN model outputs to measured data. Parameterization of different tomato treatments helps the generalization of experimental findings. Both measurements and simulation results show that N losses via nitrate leaching can be minimized by the use of slow‐release N fertilizer in the establishment period of the crop and by application quick release N fertilizer topdressings after the roots proliferated in the deeper layers. The coupled SOIL and SOILN general models were suitable for the simulation of soil water and N transport and crop growth in the conditions of intensive tomato production.