Title: Evaluation of precision litter application practices for cotton production and soil properties Authors
Submitted to: National Cotton Council Beltwide Cotton Conference
Publication Type: Abstract Only
Publication Acceptance Date: October 14, 2011
Publication Date: January 17, 2012
Citation: Adeli, A., Jenkins, J.N., McCarty Jr., J.C., Tewolde, H., Read, J.J. 2012. Evaluation of precision litter application practices for cotton production and soil properties. National Cotton Council Beltwide Cotton Conference, January 3-6, 2012, Orlando, FL. CD-ROM. Technical Abstract: Broiler litter is typically land applied by surface broadcasting, a practice that exposes litter nutrients to volatilization or runoff losses. Placing litter in narrow bands below the soil surface may mitigate those losses and improve plant growth development, yield and quality. This study was conducted in 2009, 2010 and 2011 to determine the effects of subsurface banding of pelletized litter relative to inorganic fertilizer on cotton growth, yield and soil properties as influenced by Flue Gas Desulfurization (FGD gypsum)(a coal combustion by-product) under both drip irrigation and non-irrigation systems. A randomized complete block split-split plot design was used in which the main plots were drip irrigation vs. none; split plots were Flue Gas Desulfurization gypsum vs. none and split-split plots were inorganic fertilizer (at the rate of 120 lb N/ac, pelletized litter (at the rate of 6.7 Mg/ha) and unfertilized control. Each treatment was replicated 4 times. Each plot had six rows spaced 0.97 m apart and about 27 m long. Flue Gas Desulfurization (FGD gypsum) was applied broadcast at the rate of 2.2 Mg/ha. A GPS-guided tractor was used to plant cotton, apply the pelletized litter and side dress the N fertilizer in precise subsurface bands so that the seed and fertilizers are placed in exactly the same place year after year. Initial soil samples were taken and analyzed for chemical and biological properties. At peak blooming a of total 20 leaves were taken randomly from the two middle rows for N concentration. Leaf chlorophyll content was also measured using a hand-held SPAD meter. At open boll stage, whole plant samples were taken from 50 cm in rows, bolls were separated, dried separately, ground and analyzed for nutrient concentrations. Before harvesting, plant fruiting maps at end of season were completed to measure time scale of boll setting. All six rows were harvested using a two row picker and yield was determined. End-season soil samples were taken after harvest and analyzed for physical and chemical properties. Precise subsurface banding of pelletized litter at the rate of 6.7 Mg ha-1 was more effective in improving soil physical and chemical components such as total C and soil aggregate stability than conventional fertilizer. Regardless of irrigation and N source, FGD gypsum resulted in increasing soil aggregation which has a great role in protecting soil C from decomposition. The FGD gypsum seems to be more effective in increasing seed cotton yield under dry land conditions. In 2011, seed cotton yield from litter application was equivalent with the yield produced with inorganic fertilizer at the recommended rate of 134 kg N ha-1. This indicates that continuous subsurface pelletized litter application to cotton at the same location for three years builds up soil fertility and provides N at the rate needed for optimum yield.