USE OF INNOVATIVE TOOLS TO INCREASE NITROGEN USE EFFICIENCY AND PROTECT ENVIRONMENTAL QUALITY IN CROP ROTATIONS.

Authors: Delgado, Jorge; RISTAU, R - CO DEPT PUB HEALTH/DENVER; DILLON, M - CSU-SLVRC, CENTER, CO; Duke, Harold; STUEBE, A - USDA-NRCS, SAN LUIS, CO; Follett, Ronald; Shaffer, Marvin; RIGGENBACH, R - USDA-NRCS, CANON CITY, CO; SPARKS, R - USDA-NRCS, ALAMOSA, CO; THOMPSON, A - SCU-SLVRC, CENTER, CO

Submitted to: Communications in Soil Science and Plant Analysis
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/24/2000
Publication Date: 5/8/2001
Citation: Delgado, J.A., Ristau, R.J., Dillon, M.A., Duke, H.R., Stuebe, A., Follett, R.F., Shaffer, M.J., Riggenbach, R.R., Sparks, R.T., Thompson, A. 2001. Use of innovative tools to increase nitrogen use efficiency and protect environmental quality in crop rotations. Communications in Soil Science and Plant Analysis. 32:1321-1354.

Interpretive Summary: There are several alternatives that can be used to improve N use efficiency (NUE) for specific cropping systems depending on geographical areas, crop rotations, varieties and several other factors. Incorporation of crops that can serve as N scavengers and can potentially help to conserve soil and water quality while increasing the NUE, could be a significant contribution to environmental conservation. However, this will depend on the region, management practices such as irrigation, and other factors. The use of computer models to evaluate the impacts of BMPs on NUE for site specific fields can potentially serve as tools to assess the viability of different management scenarios across different regions. When viable, deeper rooted small grains can significantly contribute to increasing the NUE of the rotation by scavenging N leached below the root zone of shallow rooted crops. Computer models and new tools that can assess the N status of fthe aboveground canopy, such as chlorophyl levels, sap NO3- -N concentrations and N indices, and other new technologies such as precision farming, and remote sensing, will contribute to increased improvement in nutrient management in the new millennium, increased nutrient use efficiency, to conserve environmental quality, and to improve product quality at the farm level for the benefit of producers, processors and consumers.

Technical Abstract: Cropping systems grown over sandy coarse soils are susceptible to nutrient leaching due to local thunderstorms and irrigation. Additionally, erosion c contribute to removal of nutrients, soil organic matter, and fine particles Balancing nutrients for these systems while protecting water and soil quali requires best management practices (BMPs). Crop rotations with deeper roote esmall grains and winter cover crops reduced potential losses of fine particles, soil organic matter, nitrogen, and other nutrients due to wind erosion and protected soil and water quality. The cropping system N status can be monitored by assessing chlorophyll, sap NO3- -N concentrations and N indexes of the canopy. The Nitrogen Leaching Economic Analysis Package (NLEAP) model simulated residual soil NO3- -N and soil water and showed th there is potential to use precision farming to improve NUE. Simulations of the system showed that BMPs increased NUE and that NO3- -N can potentially ybe removed from the shallow underground water table protecting water quali These results show that with the application of models, and tools to monit the N status of the aboveground canopy, such as chlorophyl readings, sap NO3- -N concentrations, N indices, and other new technologies such as precision farming and remote sensing, nutrient use efficiency in the new millennium will be significantly increased, environmental quality will be conserved, and product quality will be improved at the farm level for the benefit of producers, processors and consumers.