|SHANKLE, MARK - Mississippi State University|
|Way, Thomas - Tom|
Submitted to: Soil Science Society of America Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/28/2018
Publication Date: 12/3/2018
Citation: Tewolde, H., Shankle, M.W., Way, T.R., Pote, D.H., Sistani, K.R. 2018. Poultry litter band placement in no-till cotton affects soil nutrient accumulation and conservation. Soil Science Society of America Journal. 82:1459-1468. https://doi.org/10.2136/sssaj2018.04.0131.
Interpretive Summary: Dry to semi-dry manures traditionally are applied using mechanical spreaders that scatter the manure over the soil surface covering a swath width of as much as 30 to 40 feet. Throwing manure to such distances leads to uneven distribution on the soil surface and exposes the manure to greater losses of its components before and after the manure lands on the soil surface. In an effort to find better ways of applying the litter for crops, USDA-ARS engineers and scientists have developed prototype implements that place dry litter in narrow bands below the soil surface protected from exposure. Such placement has been shown to reduce loss of manure nutrients to runoff with better implications for the environmental. The benefits of applying litter in bands could further be improved by finding proper placement in terms of band spacing. In this study we investigated whether poultry litter band placement affects the accumulation, conservation, and accessibility of selected mineral nutrients in a no-till cotton production system. The results showed an application of about 2.5 tons/acre poultry litter for three consecutive years, regardless of how it was applied, leads to accumulation of the plant nutrients phosphorus (P), potassium (K), magnesium (Mg), zinc (Zn), and copper (Cu) in the soil after growing and harvesting several cotton crops. However, the accumulation of these elements was greater when the litter was applied by subsurface rather than by surface banding. Litter, despite adding a 3-year total of 11.3 lbs/acre manganese (Mn) to the soil, reduced the level of Mn by 20% in the soil and by as much as 40% in cotton plant tissues. This reduction may be significant because Mn at high levels in the acidic soils of the southeastern US may be harmful to cotton and other crop yields. Litter application did not lead to soil organic matter improvement or total soil nitrogen content, two important soil quality attributes. Overall, the results show that poultry litter applied in bands below the soil surface benefits cotton yield by enhancing the nutrient conservation and availability of most of the elements and reducing the potentially harmful effect of excess Mn in the typically acidic soils of the Southeast.
Technical Abstract: Whether subsurface poultry litter band placement relative to the plant row affects nutrient conservation on a relatively long-term basis has not been sufficiently investigated. The objective of this study was to determine whether poultry litter band placement affects the accumulation and conservation of selected soil nutrients in a no-till cotton cropping system. The treatments consisted of 6.1 Mg ha-1 broiler litter applied in subsurface bands spaced 1.02 m (wide, SSw) or 0.30 m (narrow, SSn) apart, the same litter rate applied in surface bands spaced 0.30 m apart (narrow, SFn)), an unfertilized control (UTC), and a treatment that received synthetic inorganic fertilizers based on regional soil test recommendations (Std). The results showed poultry litter, regardless of the placement, resulted in the accumulation of Mehlich 3 extractable soil P, K, Mg, Zn, and Cu but not total C or N. Litter, despite supplying a 3-yr total of 10.2 kg ha-1 Mn, reduced extractable soil Mn by an average of 20% and plant tissue Mn by as much as 40% relative to the Std treatment which may be attributed to its effect on soil reaction including pH. The accumulation of extractable soil P, K, Mg, Zn, and Cu was greater when the litter was applied by subsurface rather than surface banding, but surface banding was more effective in reducing soil and tissue Mn than subsurface banding. The SSw and SSn treatments did not show consistent differences in conservation of extractable nutrient. Overall the results show that applying poultry litter in bands below the soil surface leads to greater conservation of litter-derived mineral elements than applying the same amount above the soil surface. Poultry litter applied in bands regardless of the placement relative to plant row did not increase soil organic matter.