Nitrate leaching losses in site-specific nitrogen management in corn (Zea mays L.) crop in Inland Pampas, Argentina

MUSCHIETTI PIANA, M.P.; CIPRIOTTI, P.A.; URRICARIET, S.

Hobart

Conferencia; 5th Joint Australian and New Zealand Soil Science Conference: Soil solutions for diverse landscapes; 2012

An average 10-30% of total N inputs in cropping systems are lost due to nitrate leaching. This has led to environmental contamination and concerns regarding use of N fertilizers. Development of alternative management strategies will be vital to sustaining cereal production systems. NLEAP model was developed for a rapid and accurate estimation of potential nitrate leaching losses moving below the root zone, associated with agricultural practices. The objective of this study was to assess nitrate leaching losses in N fertilized corn crop with uniform and site-specific N technologies. N leaching losses were simulated with NLEAP model under different climatic scenarios (wet, dry and average). Soil nitrate-nitrogen and water content was determined in two moments: prior to N application and after harvest in field experiments (0-1,5 m depth) with uniform (UM) and site-specific N management (SSM). Several soil parameters were also determined under field conditions to run NLEAP. The residual nitrate content and the potential leaching losses were simulated with NLEAP and were compared with experimental data. Simulated data showed a high correlation with the observed values suggesting that NLEAP was capable to predict soil nitrate leaching under the studied conditions. In maize low-productivity zone, resource conservation was improved with SSM by reducing residual soil nitrate content that would be leached during a rainy season. SSM resulted in lower N leaching losses than UM under all climatic scenarios. We strongly encourage soil and water conservation scientists to continue looking for alternatives for managing future impacts to soil and water quality.