Water Treatment Residual to Reduce Nutrients in Surface Runoff from Agricultural Land

Abstract

Abstract Application of animal manures in excessive amounts can result in surface runoff of nutrients and degradation of surface water. Best management practices that use chemical or by‐products to sorb nutrients can reduce nutrient loss from agricultural land. The objective of this work was to determine the ability of water treatment residual (WTR) to reduce N and P runoff from land treated with poultry litter. Different WTR (ABJ or WISTER) were used in two experiments different locations. Three WTR treatments were applied to plots that received poultry litter at 6.72 Mg ha −1 broadcast on bermudagrass [ Cynodon dactylon (L.) Pers.] pasture. Treatments were broadcast (11.2 or 44.8 Mg ha −1 ), and a buffer strip (44.8 Mg ha −1 ) to the bottom 2.44 m of the plot. Experimental plots received simulated rainfall for 75 min at 6.35 cm h −1 within 24 h of litter and WTR application. Nitrogen, NH 4 , P, Al, and dissolved solids in surface runoff were determined. Mean dissolved P of 15.0 mg L −1 was reduced to 8.60 mg L −1 by the high broadcast and to 8.12 mg L −1 by the buffer strip ABJ treatments. Reductions in runoff P were attributed to amorphous Al in the WTR. Soluble NH 4 ‐N was reduced from 33.7 to 11.3 mg L −1 (high broadcast) and to 17.9 mg L −1 (buffer strip) by ABJ. WISTER did not, however, reduce soluble NH 4 ‐N or total N. Reduction in NH 4 ‐N was related to cation‐exchange capacity of the WTR. Land application of WTR did not increase dissolved solids or Al in surface runoff.