Corn yield, phosphorus uptake and soil quality as affected by the application of anaerobically digested dairy manure and composted chicken manure

The excessive accumulation of animal manure in livestock production units has made manure a valuable phosphorus (P) source that if used efficiently can be a sustainable alternative to mineral P fertilizer. A two-year field experiment was conducted at Paterson, South Central Washington, to assess corn (Zea mays L.) grain yield, tissue P concentrations, soil quality indices and Olsen P test in soils amended with composted chicken manure, anaerobically digested dairy manure (AD dairy manure) and mono-ammonium phosphate (MAP). Treatments were applied using four rates. There was no significant grain yield and grain P response to fertilizer treatments. Corn leaf P concentration was significantly higher when application rate was twice (40 kg P ha(-1)) and four times (80 kg P ha(-1)) the recommended rate relative to the no-P control treatment. At these higher P application rates, leaf P from plots receiving composted chicken manure and AD dairy manure were comparable to leaf P concentration in the MAP treatment. Soil Olsen P test increased with application rate, although increases were not always statistically significant. Soil quality indices for both years did not differ significantly for the two-manure derived P sources vs mineral P fertilizer. These results suggest that changes in soil quality indices should not be expected change within 2 years of using manure derived P