Assessing Soil Phosphorus Status in Poultry Production Areas of Mississippi.

Applying animal manure to farmland is an appropriate and environmentally sound management practice for livestock and poultry producers. Land applications recycle nutrients from manure to soil for plant growth, increasing organic matter to improve soil structure and water holding capacity. As with other nutrient sources, improper use of manure can result in environmental damage. One of the major concerns associated with manure application is the buildup of phosphorus (P) in soils, and the subsequent impact of P on surface water quality. An assessment was developed to increase understanding of the P status in soils of the top 20 poultry production counties in Mississippi. The study performed a descriptive summary and analysis of temporal dynamics of STP in 15,057 soil samples, submitted for forage and pasture crop recommendations, after analysis by the Mississippi State University Extension Service Soil Testing Laboratory for 10 annual periods from 2002 to 2012. There were gradual annual changes in STP level ranges from the first (5 to 3780 lb ac^-1) to the last year (5 to 3980 lb ac^-1). Individual peak STP values of 5990 and 4840 lb ac^-1 were observed in the 2nd and 7th year, respectively. However, mean STP levels increased from 113 lb ac^-1 to 302 lb ac^-1 from the first to the last year with the highest mean STP level of 356 lb ac^-1 in the 7th year. The MSU Extension Service would not recommend additional external P for 69% of the soils sampled in the last year of the dataset. These results indicate increased STP in these soils that could contribute P to runoff and leaching flows. Comprehensive nutrient management plans should be developed and implemented for all poultry production operations for the optimal use of poultry manure.