1a. Objectives (from AD-416):
The objective of this study is field evaluation of nitrogen availability from fresh and pelletized litter for corn production. Most of the studies on evaluating manure on N availability have been conducted in a completely controlled condition using incubation studies in the laboratory with no crop or greenhouse studies using crops for biomass production. Prediction of manure nitrogen availability in the field to crops is key to ensuring adequate nutrient supply to maximize yields while avoiding over application and minimizing adverse environmental impact. Currently, broiler litter is being pelletized to increase the economic feasibility of transporting broiler litter from the production areas to the places it is needed such as row crops. Fresh broiler litter has been used for row crops as an alternative source of fertilizer N but pelletized litter has not been used on row crops yet, probably because of the price. Field studies comparing these two types of broiler litter are necessary to provide more information for the farmers who might be interested in using pelletized litter on their row crops in the near future.
1b. Approach (from AD-416):
This study will be conducted in a no-till corn at a private farm near Caledonia, MS. Treatments will consist of three N sources and four rates. The N sources include inorganic fertilizer N (ammonium nitrate), pelletized poultry litter (PPL), and fresh poultry litter (FPL). Fresh and pelletized litter will be applied at the total N rate of 0, 124, 248, and 496 lb/acre. Inorganic fertilizers will be applied at the rate of 0, 80, 160, and 240 lb N acre. Corn plant samples will be collected at the sixth-leaf (V6), 12th-leaf (V12), tassel (VT), and physiological maturity (R6) growth stages for dry matter production and N uptake estimations. Grain yield and grain N uptake will be determined. For each rate and source, grain N recovery will be calculated. Post-harvest residual inorganic N will be determined. Using all above mentioned factors and fertilizer N equivalence method based on grain yield and grain N uptake, the available N from total N applied by fresh and pelletized litter will be estimated in the field condition. Also the corn harvest index will be determined as a ratio of corn grain yield to above ground biomass without corn grain at physiological maturity, economic optimum N rate, and maximum N rate in relation to corn grain yield will be determined for both fresh and pelletized broiler litter. The effects of timing (fall vs spring), placement (band vs broadcast) on available N will also be evaluated for both fresh and pelletized litter.
3. Progress Report:
Both fresh and pelletized litters were applied at the rates providing 200 lb of nitrogen (N) per acre. Inorganic fertilizer N was applied to corn at the rate equivalent to poultry litter. Treatments consisted of an unfertilized control, two types of broiler litter (pelletized and non-pelletized), and two litter placements (broadcast and subsurface band), and a standard fertilization with inorganic fertilizer at the rate of 200 lb N per acre as recommended by the Mississippi State University Soil Testing Laboratory applied as urea ammonium nitrate (UAN) (32% N) with about 10 lb/acre injected at planting and the rest applied around the V6 growth stage. The UAN was injected into the soil about 0.15 to 0.20 m to the side of the row. Corn grain yield, N uptake and residual soil N were determined for all N sources. Nitrogen availability was one of the most critical factors to maximize yield of corn and was influenced by the type and method of application of the N sources. In this study, surface broadcast of pelletized litter had a greater effect on increasing corn grain yield and N utilization than non-pelletized litter. Apparently subsurface banding of non-pelletized broiler litter increased corn N utilization and produced more grain than surface broadcast litter. This study indicated that subsurface banding of broiler litter could be considered as an effective management practice for no-till corn production, and if the method can be developed as a practical option for the producers it can help solve water-quality problems associated with surface runoff loss of nutrients from no-till fields receiving poultry manure as surface broadcast applications. A study was also conducted in no-till cotton. Treatments included using flue gas desulfurization (FGD), as main plot at the rate of 0, 0.5, 1, and 1.5 tons per acre and broiler litter types (pellet vs. fresh), inorganic fertilizer and control (no fertilization) as subplots. For both types, broiler litter was applied at the rate of 4 tons/acre, inorganic N at the rate of 125 lb N per acre and no fertilization (control). The results indicated that co-application of FGD gypsum at the rate of 1 ton per acre with fresh, pelletized litter and inorganic fertilizer was agronomically beneficial because cotton lint yield was increased by 16, 25 and 22% compared to fresh, pelletized litter and inorganic fertilizer N alone. Also, mixing broiler litter with FGD gypsum reduced soil water soluble P by 53% as compared to litter application alone with no negative effects on cotton yield. A manuscript will be submitted.