Remediation of Soil Nutrient Accumulations Following Poultry Litter Application.

Poultry litter can be an excellent source of nutrients for crop production.  If properly managed, litter can be returned to land; however, one major problem of poultry litter application to land is soil nutrient accumulation.  Applying poultry litter to land at recommended crop N rates can lead to an accumulation of P, K, and some micronutrients in the soil.  This study was developed to observe how soils that contained nutrient accumulations from poultry litter application could be remediated through prescription based inorganic fertilizer additions.   Poultry litter application occurred from 2001-2004, followed by half of the plots receiving the remediation treatments in 2005-2009.  In 2005-07, orchardgrass hay was the crop utilized while in 2008-09, corn was the crop.  This paper will examine the effects seen during the corn crop in 2008-09.  A completely randomized block design consisting of four original  treatments was utilized.  The original treatments were inorganic N, P, K fertilizer (I), poultry litter applied according to recommended P rate (PPL), poultry litter applied according to recommended N rate (NPL), and poultry litter applied at recommended P rate with supplemental inorganic N fertilizer (NPPL).  Remediation treatments involved using inorganic fertilizers on all treatments based on soil tests.  These are RI, RNPL, RPPL, and RNPPL in sequence from previous treatments.  Soil samples were compared between initial nutrient content and content in March 2008 and 2009.  Samples were analyzed for pH, CEC, organic matter and available nutrient content.   Indications are that the remediation process is lowering some nutrient concentrations, but most are still at much higher levels when poultry litter application was originally based on N needs.