Enhancing management of fall-applied poultry litter with cover crop and subsurface band placement in no-till cotton

Authors: Tewolde, Haile; SHANKLE, MARK - Mississippi State University; Way, Thomas - Tom; Adeli, Ardeshir; Brooks, John; He, Zhongqi

Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/23/2014
Publication Date: 2/25/2015
Publication URL: http://handle.nal.usda.gov/10113/60914
Citation: Tewolde, H., Shankle, M.R., Way, T.R., Adeli, A., Brooks, J.P., He, Z. 2015. Enhancing management of fall-applied poultry litter with cover crop and subsurface band placement in no-till cotton. Agronomy Journal. 107:449-458.

Interpretive Summary: Row crop farmers prefer to apply poultry litter in the fall to fertilize spring-planted crops primarily because they are too busy with other routine farm operations in the spring. But applying litter in the fall in regions with warm fall or winter months increases the risk of losing the litter value and environmental contamination. In this 6-year field research, we studied if a combination of applying the litter by subsurface banding (which is a relatively new method of application) and overplanting with cover crop can make fall-applied litter as effective as spring-applied litter for no-till cotton. The results showed that planting wheat as a winter cover crop, regardless of how the cotton was fertilized, increased cotton lint yield by as much as 18% in the driest season. There was no cotton yield benefit from use of winter cover crop in wet years. Applying litter in the fall leads to loss of litter-derived nutrients; but applying the litter in subsurface bands, instead of the conventional surface broadcast, reduced this loss regardless of the presence of cover crop. Applying litter in subsurface bands in conjunction with winter cover crop increased cotton lint yield, relative to broadcast application with no cover crop, by as much as 22%. This combined benefit of cover crop and subsurface banding of the litter suggests that litter may be applied in the fall in these soils without yield penalty and with the potential to reduce the litter amount and minimize environmental contamination.

Technical Abstract: Whether yield reduction risk of cotton fertilized with fall-applied poultry litter in regions with warm fall or winter months can be minimized by applying the litter in subsurface bands in conjunction with winter cover crop is unknown. A field study was conducted in Mississippi to test whether litter applied in the fall can be as effective as litter applied in the spring for no-till cotton if applied in narrow subsurface bands in the presence of a winter cover crop. The study compared ˜5.6 Mg ha-1 poultry litter applied in the fall vs. spring, in subsurface bands vs. surface broadcast, with winter cover crop vs. no cover crop as a 2×2×2 factorial treatment structure. An unfertilized control, and a standard fertilized with conventional inorganic fertilizers were included. The results showed that planting wheat as a winter cover crop, relative to no cover crop, increased cotton lint yield by as much as ˜18% in the driest season. Applying litter in the fall leads to loss of litter-derived nutrients but this loss did not lead to lint yield reduction. Litter nutrients are conserved better if applied in subsurface bands than by surface broadcast regardless of the presence of cover crop. Applying litter in subsurface bands in conjunction with winter cover crop increased cotton lint yield, relative to broadcast application with no cover crop, by as much as 22%. This combined benefit of cover crop and subsurface banding of the litter suggests that litter may be applied in the fall in these soils without yield penalty and with the potential to reduce the litter rate and minimize environmental contamination.