Recovery of Phosphorus in Soils Amended with Manure for 119 Years

Abstract

Manure phosphorus (P) accumulation in soils is of environmental concern. The objectives were to determine P concentrations and fate in soils following 119 years of manure and 89 years of chemical fertilizer application. The recovery and distribution of P were evaluated for five years in soils from the untreated check, and soils amended with manure, fertilizer-P, or NPK. Total P concentrations were significantly higher in fertilizer-treated surface soils, compared to manure application. Treated plots had significantly higher P concentrations than the check. Virtually all of the added P was accounted for, either remaining in the soil or harvested in grains. Over 50% of fertilizer-P and about 38% of manure-P were found in the top 15 cm of the soil. A majority (81–99%) of the added fertilizer-P was found in the top 30 cm, while about 40% of manure-P leached down to the 30–90 cm level of the soil profile. Following 119 years of moderate application, manure-P did not reach deeper than 90 cm, suggesting that leaching to groundwater is not a concern at this site. Preserving P in the lower soil profile could enhance the potential for plant uptake.