Biogeochemical Models Relating Soil Nitrogen Losses to Plant-Available N

Abstract

Four biogeochemical models that simulate N cycling in the plant-soil-water-atmosphere environment are evaluated. Each model considers N inputs and outputs to an agricultural system with emphasis on the relationships between mineral fertilizers and biofertilizers to plant-available N. Efficient use of N fertilizers by minimizing losses of N by NO₃^- leaching, NO_x off-gas, and erosion decreases any negative impact on the environment and reduces the drain of natural resources and economic loss. A review of four existing models is conducted to evaluate the effectiveness of these models in simulating major biogeochemical relationships of added N to agricultural systems. The APS simulation model focuses on the influence of N fertilization on CO₂ emissions with varying soil temperature. The deterministic DAISY model simulated nitrate leaching in an effort to develop sustainable crop rotations. The NLEAP model simulates nitrate leaching and allows users to evaluate various agricultural management strategies. The physically based analytical model RISK-N simulates N fluxes for major processes involving N in soil, and seems best suited for modeling the full complex of biogeochemical N cycles in fertilized systems.