EVALUATION OF EPIC FOR A SHALLOW NEW ENGLAND SOIL: I. MAIZE YIELD AND NITROGEN UPTAKE

Abstract

Predictions of maize (Zea mays L.) silage yields and nitrogen (N) uptake from the Erosion-ProductivityImpact Calculator (EPIC) model were compared with observed values from plots located in Connecticut. The soil was afine sandy loam underlain by a compact glacial till. The influence of soil parameters was assessed by comparing resultsusing EPIC default versus measured soil parameter values. This article addresses the comparisons for maize yield and Nuptake under five rates of N fertilization across three different growing seasons. Statistical analyses showed that the EPICmodel in general under-estimated both maize yield and N uptake. The accuracy of predicted values for both yield and Nuptake were affected by both growing season precipitation and N application rate. Possible reasons for the influence ofthese factors on EPIC predictions are given.