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
As agricultural input costs for row crops have reduced growers’ profits, interest in using poultry litter as an important alternative source of nutrients for crop production has increased. No-till crop production has become the most common form of conservation tillage in corn in the U.S., with approximately one million acres of no-till corn in the southeastern United States in 2004. Adoption of a no-till system and use of poultry litter as alternatives to conventional tillage and inorganic fertilizers may help corn producers economically boost corn grain yield. However, manure application to no-till, where incorporation is not permitted, may reduce its effectiveness as a nutrient source because of potential nitrogen (N) loss via runoff and ammonia volatilization. The N sources included inorganic fertilizer, pelletized and non-pelletized broiler litter. Treatments were an unfertilized control, inorganic N fertilizer at the rate of 180 kg ha-1, sub-surface and surface broadcast of non-pelletized and pelletized litter at the rate of 11.2 Mg ha-1 which provided an average of 342 kg total N ha-1 of which we assumed 50% mineralization (171 kg available N ha-1) during the corn growing season. Inorganic N fertilizer was applied at the rate of 180 kg N ha-1 recommended by the Mississippi State University Soil Testing Laboratory. 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. No differences in grain yield, total N uptake, and apparent N use efficiency were obtained between pelletized and non-pelletized litter when sub-surface banded. However, for surface broadcast the values were greater for pelletized than non-pelletized litter. Non-pelletized litter applied in a sub-surface band had 16% greater grain yield, 9% higher harvest index, 19% more N utilized and 56% greater in apparent N use efficiency compared with surface broadcast. Sub-surface banding of non-pelletized litter is an effective way of delivering litter-derived nutrients which is agronomically and environmentally sound. The results of this management practice on corn grain yield and soil test nutrient levels were compiled and summarized as individual farm reports for the cooperator’s information and forwarded to the farmer. The ADODR monitored this project with frequent discussions and contact with the principal scientist involved in this research.