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INVESTIGATOR: Tharayil, N.

PERFORMING INSTITUTION:
CLEMSON UNIVERSITY
CLEMSON, SOUTH CAROLINA 29634

ENHANCING THE NUTRIENT USE EFFICIENCY IN CROP PLANTS BY TAILORING THE NITROGEN AND PHOSPHOROUS RELEASE RATES FROM RENDERED ANIMAL MATERIALS

NON-TECHNICAL SUMMARY: Faced with a steadily dwindling cropping area, current agricultural practices overly rely on chemical fertilizer inputs to boost crop productivity. Present-day agriculture relies heavily on nutrient rich inorganic and chemical forms of nitrogen (N), including urea, ammonium salts, and nitrate salts. This approach results in high nitrogen delivery over a short time that exceeds the capacity for plant uptake, thus resulting in diminished nutrient use efficiency and greater environmental pollution. The reserve of phosphate rock, which currently accounts for 75% of the phosphorous (P) fertilizers, is dwindling at an alarming rate due to the burgeoning demand for P fertilizers. Moreover, the current production practices of nitrogen and phosphorous are highly energy intensive and not sustainable. The proposed approach is to revisit a historically employed fertilizer matrix; rendered animal proteins. The proposed research will develop new formulations of fertilizers, focusing on maximizing the nutrient use efficiency while employing economically feasible source materials. The proposed approach will utilize rendered animal proteins that are unsuitable for feed applications as a base matrix for supplying nitrogen and phosphorous to crops, thus recapture and reuse the nutrients from a resource which otherwise will be discarded. The project will employ various natural plant-based amendments that are spent-waste, to tailor the nutrient release rate from these RM so as to match the nutrient uptake rate of the crops, thus facilitating higher nutrient use efficiency. The project team proposes to produce a pelletized material of varying formulations of RM and amendments and test the nitrogen and phosphorous use efficiency on food crops in greenhouse and field conditions. The proposed recycling of reactive forms of nutrients in animal and plant byproducts will enhance the long-term sustainability of crop production systems by promoting the biological health of soils that is diminished by long-term, exclusive use of inorganic fertilizers. Results from this work will be applicable to other organic fertilizers that include agricultural and municipal wastes.

OBJECTIVES: The production of inorganic fertilizers is highly energy intensive and not sustainable; however, the current agricultural practices greatly dependent on the use of chemical fertilizers to meet the ever burgeoning demand for food production. Because of the fixed nitrogen production capacity of the US, more than 50% of the nitrogen (N) fertilizer demand is met through imports. Furthermore, while the US is the largest exporter of phosphorous (P) fertilizers, the reserve of phosphate rock, which currently accounts for 75% of the P fertilizers, is predicted to be depleted by 2050. In many production systems less than 50% of applied N and 20% of the applied P is taken up by plants and converted to biomass. The high application rate of synthetic fertilizers, combined with low plant utilization results in severe environmental pollution. The current adoption of organic manures is plagued by N loss during storage leading to inconsistent nutrient delivery, and the consequential environmental pollution. The proposed project will utilize various natural amendments to tailor the nutrient release rate from rendered animal proteins (RM) in order to match the nutrient uptake rate of the crops, thus facilitating higher nutrient use efficiency, better soil health, reduced negative environmental impact, and produce quality.The major goal of this project is to substantially improve N and P use efficiency in managed agroecosystems through the efficient and economical recapture and reuse of nutrients in proteinaceous organic amendments, which would otherwise be landfilled, and would potentially be a source of environmental pollution. This will be achieved through 1) modeling the mechanisms and rates of nutrient mineralization and release from RM and 2) modulating the rate of nutrient release from RM by using synthetic and natural compounds that regulate specific steps in the N and P mineralization process, so as to match the nutrient uptake rates of the crop plants.Our specific objectives are to:Characterize the fundamental mechanisms and rates of nutrient mineralization processes from RMTailor the N and P release rate from RM using various synthetic and natural compounds that regulate different steps in the mineralization process,Measure efficiency of N and P use of food crops from RM in greenhouse and field trials.Monitor changes in soil health and quality of produce following partial substitution of traditional fertilizer regime with the optimized RM fertilizer formulations.The fact that the RM can be better characterized and is not time sensitive like other N-rich organic amendments makes it a viable candidate for studying the fundamentals of nutrient release from nitrogenous organic amendments and their influence on soil microbial communities that sustain crop production. Results from this work will be applicable to other organic fertilizers that include agricultural and municipal wastes.