Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 11/1/2009
Publication Date: 11/1/2009
Citation: Kovar, J.L., Moorman, T.B., Cambardella, C.A., Singer, J.W., Tomer, M.D. 2009. Phosphorus in Soil and Runoff Following Swine Manure Injection with a Low-Disturbance Applicator [CD-ROM]. In: ASA-CSSA-SSSA Annual Meeting Abstracts, Nov. 1-5, 2009, Pittsburgh, PA. Paper No. 270-7.
Technical Abstract: Injection of liquid swine manure disturbs surface soil, making it susceptible to erosion. Runoff from treated lands can transport nutrients and pathogens to surface waters. Our objective in this field study was to determine the effect of two swine manure application methods on phosphorus (P) fate and transport in a corn (Zea mays L.) production system with and without cover crops. The experimental design (RCB; four replications) included six treatments: i) no manure, with and without a ryegrass cover crop; ii) conventional knife injection of manure, with and without a cover crop; and iii) low-disturbance injection of manure, with and without a cover crop. Manure application supplied 168 kg N ha-1 and 72 kg N ha-1. Subsamples of runoff generated with a rainfall simulator were collected for analysis of dissolved reactive P, total P, and total suspended solids. Rainfall was applied 8 days after manure application (early November) and in mid-April. Soil P availability was assessed with anion exchange membranes inserted to 30 cm within and perpendicular to the row. Manure application method had little effect on DRP, TP, and TSS in runoff. However, all three measures were significantly higher in manured plots than in control plots. The ryegrass cover crop reduced P and sediment losses from plots with manure applied by either method, as well as from plots without manure. Manure application significantly increased available P in the soil. The highest P levels (21-27 ug P cm-2) were detected in the 20-30 cm layer of plots with conventional manure application, while in plots with low-disturbance manure application, the highest P levels (25-27 ug P cm-2) were detected in the 5-20 cm layer. Results suggest that low-disturbance application of swine manure into a standing cover crop would minimize P losses and provide optimum P availability to the subsequent corn crop.