Nutrient migration from agricultural land to freshwater resources is a fundamental global concern. The Department of Agriculture at Southeast Missouri State University has installed technology to research aspects of n...Nutrient migration from agricultural land to freshwater resources is a fundamental global concern. The Department of Agriculture at Southeast Missouri State University has installed technology to research aspects of nutrient migration and propose mitigation strategies. The installed technologies include: 1) controlled subsurface drainage and irrigation technology, 2) a denitrification bioreactor to reduce nitrate concentrations in tile-drainage effluent, 3) an off-season water storage reservoir to capture and retain nitrate-bearing tile-drain effluent which will be applied as in-season liquid fertilizer, 4) riparian buffers, and 5) cover crops. For our beef livestock operation, we are installing a constructed wetland to capture nutrient-laden runoff from manure amended pastures associated with a confined feeding facility. Modern pasture management and row-crop nitrogen research augment the environmental stewardship potential of these infrastructures, while preserving farm profitability. The goal is to demonstrate that environmental stewardship, agriculture production and farm profitability are synergistic and may be explicitly demonstrated to the agriculture community.展开更多
Nitrogen transport from agriculture production fields raises the specter of environmental degradation of freshwater resources. Our objectives were to document and evaluate nitrate-N, ammonium-N, phosphorus and other n...Nitrogen transport from agriculture production fields raises the specter of environmental degradation of freshwater resources. Our objectives were to document and evaluate nitrate-N, ammonium-N, phosphorus and other nutrients emanating from a 40-ha controlled subsurface irrigation drainage technology coupled in series with a denitrification bioreactor. The intent of the denitrification bioreactor is to create an environment for anoxic microbial populations to support denitrification. We monitored the tile-drainage effluent and denitrification bioreactor water chemistry under a corn-soybean rotation to estimate the nutrient concentrations and the competence of the denitrification bioreactor to foster denitrification. Nitrate-N bearing tile drainage effluents ranged from less than 1.5 to 109 mg NO3- -N/L, with the nitrate concentration differences attributed primarily to the: 1) timing of nitrogen fertilization for corn, 2) soil mineralization and residue decomposition, and 3) intense rainfall events. The denitrification bioreactor was highly effective in reducing drainage water nitrate-N concentrations providing the rate of water flow through the denitrification bioreactor permitted sufficient time for equilibrium to be attained for the nitrate reduction reactions. The nitrate-N concentrations entering the denitrification bioreactor ranged from 0.4 to 103 mg NO3-?-N/L in 2018, whereas the outlet nitrate concentrations typically ranged from 0.3 to 5.2 mg NO3- -N/L in 2018. Nitrate tile-drainage effluent concentrations in 2019 were marginal, given soybeans obtain nitrogen from biological nitrogen fixation. Nutrient uptake by corn reduced the soil nitrate leaching pool and created nitrogen-bearing biomass, features important for formulating best management practices.展开更多
文摘Nutrient migration from agricultural land to freshwater resources is a fundamental global concern. The Department of Agriculture at Southeast Missouri State University has installed technology to research aspects of nutrient migration and propose mitigation strategies. The installed technologies include: 1) controlled subsurface drainage and irrigation technology, 2) a denitrification bioreactor to reduce nitrate concentrations in tile-drainage effluent, 3) an off-season water storage reservoir to capture and retain nitrate-bearing tile-drain effluent which will be applied as in-season liquid fertilizer, 4) riparian buffers, and 5) cover crops. For our beef livestock operation, we are installing a constructed wetland to capture nutrient-laden runoff from manure amended pastures associated with a confined feeding facility. Modern pasture management and row-crop nitrogen research augment the environmental stewardship potential of these infrastructures, while preserving farm profitability. The goal is to demonstrate that environmental stewardship, agriculture production and farm profitability are synergistic and may be explicitly demonstrated to the agriculture community.
文摘Nitrogen transport from agriculture production fields raises the specter of environmental degradation of freshwater resources. Our objectives were to document and evaluate nitrate-N, ammonium-N, phosphorus and other nutrients emanating from a 40-ha controlled subsurface irrigation drainage technology coupled in series with a denitrification bioreactor. The intent of the denitrification bioreactor is to create an environment for anoxic microbial populations to support denitrification. We monitored the tile-drainage effluent and denitrification bioreactor water chemistry under a corn-soybean rotation to estimate the nutrient concentrations and the competence of the denitrification bioreactor to foster denitrification. Nitrate-N bearing tile drainage effluents ranged from less than 1.5 to 109 mg NO3- -N/L, with the nitrate concentration differences attributed primarily to the: 1) timing of nitrogen fertilization for corn, 2) soil mineralization and residue decomposition, and 3) intense rainfall events. The denitrification bioreactor was highly effective in reducing drainage water nitrate-N concentrations providing the rate of water flow through the denitrification bioreactor permitted sufficient time for equilibrium to be attained for the nitrate reduction reactions. The nitrate-N concentrations entering the denitrification bioreactor ranged from 0.4 to 103 mg NO3-?-N/L in 2018, whereas the outlet nitrate concentrations typically ranged from 0.3 to 5.2 mg NO3- -N/L in 2018. Nitrate tile-drainage effluent concentrations in 2019 were marginal, given soybeans obtain nitrogen from biological nitrogen fixation. Nutrient uptake by corn reduced the soil nitrate leaching pool and created nitrogen-bearing biomass, features important for formulating best management practices.
