Extractable Soil Mineral Elements Following Poultry Litter Application By Surface and Subsurface Band Applications in a No-till Cotton System.

Poultry litter and other semi-dry solid manures are traditionally applied by surface broadcasting, an inefficient practice that leads to loss of nutrients. Placing poultry litter in narrow bands below the soil surface has been shown to be an effective method for reducing such losses on a short-term basis. Whether such reductions lead to nutrient conservation on a longer-term basis is not very clear. The objective of this study was to determine whether poultry litter applied in bands above versus below the soil surface and in narrow versus wide spacing between two consecutive bands affects the accumulation and conservation of selected plant nutrients in a no-till cotton cropping system. Poultry litter (6.2 Mg/ha) was applied by subsurface banding with wide (1.02 m) spacing (SSw), subsurface banding with narrow (0.30 m) spacing (SSn), and surface banding with narrow (0.30 m) spacing (SFn). An unfertilized control (UFC) and a treatment that received synthetic inorganic fertilizers based on regional recommendations (Std) were included. The results showed applying poultry litter regardless of the method resulted in the accumulation of extractable P, K, Mg, Zn, and Cu following 2 to 3 yr consecutive litter applications regardless of the method of application. The conservation of extractable elements, however, was greater when the litter was applied by subsurface rather than surface banding which may be considered equivalent to the conventional surface broadcast method of application. The wide and narrow band spacings did not show clear differences in extractable nutrient conservation. Overall, the results show that subsurface banding, regardless of the spacing, leads to conservation of litter-derived soil mineral elements better than surface banding or surface broadcasting.