Evaluating Soil Tests to Predict Bermudagrass Growth in Drinking Water Treatment Residuals with Phosphorus Fertilizer

Abstract

AbstractDrinking water treatment residuals (WTRs) may serve as a soil substitute to revegetate disturbed land. This study evaluated the use of WTRs as a soil substitute and the ability of soil tests to predict P adequacy. We measured properties and nutrient content of three WTRs (Wister, Mohawk, and ABJ) and a control soil. Bermudagrass [Cynodon dactylon (L.) Pers. var. Greenfield] was grown with four P treatments (0, 50, 100, and 200 mg P kg−1). We measured available P by water, Mehlich 3 (M3P), and Olsen P soil extraction. Mean cumulative bermudagrass yields, across P treatments, were soil (20.6 g), Mohawk (23.6 g) > Wister (9.6 g) > ABJ (1.1 g). Tissue P concentrations were below adequate for WTR and available P in WTR was deficient for Wister and ABJ. Fertilizer P addition did not increase yield or tissue P of bermudagrass grown on WTR. However, bermudagrass grown on soil had increased yield and tissue P with fertilizer addition. The available P measured by soil tests was adequate for Mohawk and inadequate for ABJ, Wister, and soil. Although the M3P and OIsen P soil tests predicted P responses on some WTRs, with fertilizer addition, there was not a yield or tissue response. Water soluble P or Olsen P provide information on the ability of the WTR to support growth but not the ability to predict P adequacy. The M3P soil test overestimated plant availability of P in WTR due to the dissolution of P adsorbed by amorphous Al. Water extracts were the best predictor of P adequacy in WTR and should be used to determine P fertilizer additions to WTR.