ARS | Publication request: Runoff quality from no-till cotton fertilized with broiler litter in subsurface bands

Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 12, 2012
Publication Date: N/A

Interpretive Summary: Large quantity of cotton acreage in the upland soils of the mid-south is under a no-till system. More than two-thirds of the total U.S. broiler chicken production is produced in the southeastern United States, which generates substantial amounts of litter in the region. Broiler litter has long been recognized as a desirable organic fertilizer as it contains essential nutrients required for plant growth. As agricultural input costs for row crops have reduced growers’ profits, interest in using broiler litter as an inexpensive source of plant nutrients has been increasing in southeastern states. Application of broiler litter to surface soil concentrates nutrients at the soil surface and has resulted in substantial loss of litter nutrients in surface runoff following rain events. Placing broiler litter in narrow bands below the soil surface has been practiced as a successful technique for significant reduction of nutrient losses in surface runoff. Much of the work relating subsurface banding of broiler litter on nutrient losses in runoff has been done in pasturelands or under forage production system. No information is available on nutrient losses in runoff from no-till cotton fertilized with broiler litter in subsurface bands. No studies have been conducted to evaluate if broiler litter application, to the top of cover crop residue, affects nutrient concentrations in runoff. Therefore, the specific objective of this study was to determine the effect of broiler litter placement (sub-surface narrow band vs. surface broadcast) and cropping system (cover crop vs. no cover) on the load and nutrients concentrations in runoff from a no-till cotton in an upland soil.

Technical Abstract: Surface broadcast of broiler litter to no-till row crops exposes broiler litter to the atmosphere and rain events, enhances the potential loss of nutrients to the air and surface runoff water and may limit benefit of litter to the crops. Subsurface banding of litter could alleviate these risks. A 2-yr field study was conducted on a Falkner silt loam soil to determine the effect of broiler litter placements in combination with cropping system on runoff nutrient losses from no-till cotton in an upland soil. Treatments included surface-broadcast broiler litter applied manually, sub-surface-banded litter using tractor-drawn implement and no broiler litter, all in combination with or without winter wheat cover crop residue. Broiler litter rate was 5.6 Mg ha-1. The experimental design was a randomized complete block with a split-plot arrangement of treatments replicated three times. Simulated rainfall was used to generate runoff. In 2008, subsurface-banded litter significantly reduced runoff total C, N, P, NH4, NO3, Cu, Zn and dissolved P (DP) concentrations by 72, 64, 51, 49, 70, 36, 65 and 77% compared to surface-broadcast with similar trend in 2009. Bacterial runoff was decreased by one log with subsurface-banded litter compared to surface-broadcast. Except for C, NH4+ N and DP, the presence of winter cover crop residue did not affect the load and runoff nutrient concentrations in both years. The results indicate that subsurface-banded litter into no-till cotton substantially reduce nutrient and bacterial losses in runoff compared to common surface-broadcast.