Spacing of subsurface poultry litter bands: Influence on maize performance and nitrogen use efficiency

Poultry litter (PL) is traditionally surface broadcast to no-till maize (Zea mays L.). PL is nutrient-dense, and surface-applied PL nitrogen (N) is vulnerable to losses to the atmosphere and water systems. An application method was developed by USDA-ARS scientists for shallow subsurface banding PL to reduce ammonia (NH₃) volatilization and surface runoff. There is limited information on how this application method will affect conservation and nutrient accessibility in no-till maize. The objectives were to determine if adjusting PL lateral subsurface band placement in relation to maize rows affects nutrient use and maize yields. Treatments were a nontreated control (NTC), urea ammonium nitrate surface banded (Fert), poultry litter surface broadcast (PLBr), and three subsurface banded PL treatments. The subsurface PL treatments were one (PLSub1), two (PLSub2), or three (PLSub3) bands between maize rows. Treatments receiving N were applied at 180 kg total N ha⁻¹. Nitrogen concentration in V4 aboveground dry matter was higher in PLSub1 than PLSub2. Aboveground dry matter yields for all PLSub treatments were greater than PLBr and comparable to Fert. The PLSub1 and PLSub2 treatments resulted in maize grain yields equivalent to Fert and greater than PLBr and NTC when averaged across years. Few differences were observed in postharvest soil sample nutrient concentrations between PLSub treatments. These results suggest that subsurface banding PL can conserve N and increase no-till maize yield over traditional surface broadcast PL; however, increasing the frequency of subsurface PL bands did not clearly affect nutrient conservation or accessibility to the maize.