Inorganic fertilizers after broiler litter amendment reduce surplus nutrients in orchardgrass soils.

摘要

The common producer practice to dispose of broiler litter at high rates to forage crops allow excessive accumulation of soil nutrients. A remediation study was developed to examine if inorganic fertilizer application over the residual fertility of broiler litter would reduce surplus soil nutrients in orchardgrass (Dactylis glomerata L.) soils and to study the resulting biomass production. Three remediation treatments; inorganic fertilizer on antecedent broiler litter at the nitrogen rate (R-PLN), phosphorus rate (R-PLP), phosphorus rate with inorganic nitrogen (R-PLP+N), and inorganic fertilizer (INORG) were tested and results were compared with broiler litter at nitrogen rate (PLN) phosphorus rate (PLP), and phosphorus rate with inorganic nitrogen (PLP+N). Repeated broiler litter application at N rate led to elevate soil P, Cu, and Zn contents >200% from the initial levels. Implementing an alternative inorganic fertilizer application cycle in such soils can reduce P, Cu, and Zn levels respectively by 32 mg P kg-1 yr-1, 1.9 mg Cu kg-1 yr-1, and 2.4 mg Zn kg-1 yr-1 Remediation by inorganic fertilizer application may take at least 5 yr to reduce P, Cu, and Zn levels back to the normal range. In addition, inorganic fertilizer application over broiler litter at N rate can offer similar forage production as inorganic fertilizer and N rate broiler litter amendment. An alternative cycle of inorganic fertilizer application after broiler litter amendment can be recommended as a best management practice to remediate surplus soil nutrients in highly broiler litter impacted soils while assuring high forage production benefits.