Anion Exchange Membrane Soil Nitrate Predicts Turfgrass Color and Yield

Abstract

Desirable nitrogen (N) management practices for turfgrass supply sufficient N for high quality turf while limiting excess soil N. Previous studies suggested the potential of anion exchange membranes (AEMs) for predicting turfgrass color, quality, or yield. However, these studies suggested a wide range of critical soil nitrate‐nitrogen (NO3–N) values across sample dates. A field experiment, in randomized complete block design with treatments consisting of nine N application rates, was conducted on a mixed species cool‐season turfgrass lawn across two growing seasons. Every 2 wk from May to October, turfgrass color was assessed with three different reflectance meters, and soil NO3–N was measured with in situ AEMs. Cate‐Nelson models were developed comparing relative reflectance value and yield to AEM desorbed soil NO3–N pooled across all sample dates. These models predicted critical AEM soil NO3–N values from 0.45 to 1.4 μg cm−2 d−1 Turf had a low probability of further positive response to AEM soil NO3–N greater than these critical values. These results suggest that soil NO3–N critical values from AEMs may be applicable across sample dates and years and may serve to guide N fertilization to limit excess soil NO3–N.