Nitrate leaching reduced with Dynamic-Adaptive nitrogen management under contrasting soils and tillage

Abstract

Large temporal and spatial variability in soil nitrogen availability combined with economic risk avoidance leads many farmers across the United States to generally over-apply N fertilizers in corn (Zea mays L.) production systems. Various static N rate calculators are promoted in the United States, but new dynamic model-based decision tools allow for adaptive recommendations that account for specific production environments and weather. This field study quantified N leaching losses from a crossed design involving two tillage practices, plow and no-till, and two N management tools: (i) the Corn N Calculator (CNC), a generalized static N tool for New York State, and (ii) Adapt-N, a model-based tool that uses soil, crop and management information with real-time weather data. Corn was grown for four growing seasons on lysimeter plots on clay loam and loamy sand soil, and drain water samples were collected on 14 dates. Adapt-N and CNC showed identical yields despite an overall higher N input of 66 kg ha−1 (46%) for CNC. Concentrations of NO3+NO2 in drainage water varied by sampling date, but overall were impacted by soil type (loamy sand > clay loam) and N tool, with CNC-associated N losses 58 and 68% higher than Adapt-N for the clay loam and loamy sand, respectively. Plow till resulted in marginally higher NO3+NO2 concentrations in drainage water than no-till. Overall, this study offers field-based evidence on the agronomic and environmental benefits from N management that is adapted to growing environments (soil, management, weather).