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
Broiler litter has been used for row crops as an alternative source of nutrients in fall and spring under both no till and tillage system but the true value of this by-product is not totally clear for the farmers. We believe the most accurate method of measuring the true value of litter is by comparing yield of the crop fertilized with litter with yield of the crop fertilized with inorganic fertilizers under both tillage and no-till systems. The study was initiated on a no-till field to evaluate the broiler litter application relative to inorganic fertilizer at equivalent N rates on N availability and corn grain yield under different broiler litter management including timing and placement. The N sources included inorganic fertilizer and pelletized and fresh broiler litter. Broiler litter types were applied at the total N rate of 0, 124, 248, and 496 lb/acre and inorganic N fertilizer was applied at the rate of 0, 80, 160, and 240 lb/acre to corn based on the assumption that 50% of total N in broiler litter is available at the first year of application. Plant leaf samples were collected at beginning of silking for N concentration. At physiological maturity, whole plant samples were collected and analyzed for dry matter production and N uptake assimilation. Grain yield and grain N uptake were determined at harvesting. Using N equivalent method based on grain yield and grain N uptake, we found that 56% of total N applied as pelletized litter and 40% of total N applied as fresh broiler litter was available for corn during the first year of application. We found that placing raw broiler litter in narrow bands below the soil surface demonstrated substantial improvements in nutrient use efficiency with an average corn grain yields 31% greater compared with conventional broadcast application. Regardless of broiler litter type, N use efficiency and corn grain yield substantially were greater with spring application than the fall application where broiler litter was applied as conventional surface broadcast. This project was monitored by visiting cooperator, applying treatments, and collecting data on the farm several times during the year.