Phosphorus Dynamics in Two Poultry-Litter Amended Soils of Mississippi Under Three Management Systems

An experiment arranged in a randomized complete block design with three replications was conducted on a Lexington soil (fine-silty,mixed,active,thermic,Ultic Hapludalfs) and a Loring soil (fine-silty,mixed,active,thermic,Oxyaquic Fragiudalfs) in Mississippi from September 1997 to September 2000 on 18 runoff plots under natural rainfall condition to study the phosphorus (P) dynamics in poultry litter amended soils under three management systems combining tillage and planting date treatments to identify effective management practices in southern U.S.A.The management systems in the study were:1) tillage in the fall prior to litter application followed by a delayed planting of fall forages (CT-DP);2) tillage followed by immediate planting of the fall forage with subsequent litter application (CT-IP);and 3) no-till with planting prior to litter application (NT-IP).The results indicated that there was significant increase in soil P after 3 years of poultry litter application for both Lexington and Loring soils (P < 0.05).Based on P budget analysis,the majority of P from poultry litter application (> 90%),was accumulated in both soils.In Loring soil,soluble P mass in the runoff was significantly higher from NT-IP than from CT-DP and CT-IP over the entire study period (P < 0.01).For both soils,there were no significant differences in sediment P mass between management systems.For Loring soil,CT-DP and CT-IP were effective management practices to mitigate negative effects due to poultry litter application.