Improving Life-Cycle Nitrogen Use Efficiency And Environmental Performance Of Corn Production Through Improved Fertilizer Timing And Rate
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This project combines field experiments and climate modeling to evaluate nitrogen management strategies for corn production. Field experiments at multiple locations are testing different nitrogen application timings, rates, and methods. Preliminary results show that applying nitrogen at the V7 growth stage maintains yield while reducing nitrous oxide emissions and nitrate loss compared to pre-plant application. Climate modeling calibrated with field data predicts that split or delayed nitrogen application generally lowers emissions but the effect varies depending on weather and soil type. The overall goal is to understand how nitrogen management can improve nitrogen use efficiency and environmental performance under current and future climates.
Improving Life-Cycle Nitrogen Use Efficiency And Environmental Performance Of Corn Production Through Improved Fertilizer Timing And Rate
- 1. Overview Matching the timing and amount of N fertilizer with crop N demand has been identified as an effective measure for reducing reactive N loss. Increasingly wet springs in the main corn-growing areas of US have made N timing more crucial as early applications are subject to loss during wet weather. To make adoption choices, farmers need to understand the variability in performance and probability of undesirable outcomes. Our goal is to provide a detailed evaluation of the full life-cycle costs and benefits of N timing options within the context of a changing climate. This project combines long-term nitrogen rate field experiments with regional simulation under projected climate. Experimental data collection N timing and rate experiments are on-going at the Bradford Research Center near Columbia, Missouri. The soil is a Vertic Epiqaulf. Initiated in 2007, eight management systems with varying in N application timing, rate, and method used to determine rate are being tested in a randomized complete block experiment. A second experiment combines nitrogen and drainage management. Simulation We are using the DayCENT biogeochemical model to predict N2O emissions, nitrate loss, and yield with different nitrogen management under current and future climate. What we’ve learned so far • Soil type may be important in determining effect of N-timing on soil N2O flux. • In field experiments, N application at V7 has maintained yield, and reduced both N2O flux and nitrate loss in drainage water. • Amount and timing of rainfall result in large year-to-year variability in effect of N timing on N losses and grain yield. N2O emissions variation with timing, rate and soil type Yield and nitrate loss with N timing N2O emissions with timing of N fertilization Acknowledgements: This work is supported by the USDA National Institute of Food and Agriculture, Renewable Energy, Natural Resources and Environment program area, Grant Award No. 2015-67019-23601, Accession No. 1005802. Special thanks to Laura Smith and Jordi Francis-Clar. Improving life-cycle nitrogen use efficiency and environmental performance of corn production through fertilizer timing and rate R.P. Anex1, P.C. Scharf2, B.D. Duval3, J.S. Evans1 1Department of Biological Systems Engineering, University of Wisconsin-Madison; 2Plant Sciences, University of Missouri; 3Department of Biology, New Mexico Tech. -0.01 0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07 4/29 5/05 5/11 5/17 5/23 5/29 6/04 6/10 6/16 6/22 6/28 7/04 7/10 7/16 7/22 7/28 8/03 8/09 8/15 8/21 8/27 9/02 9/08 9/14 9/20 Nitrousoxide,kgha-1 day-1 2015 Daily flux of Nitrous Oxide Pre-plant N Sidedress at V7 Percent effect of split or delayed N fertilization -80 -60 -40 -20 0 20 40 60 80 100 Nfertilizationrate(kgN.ha-1.yr-1) 100 120 140 160 180 200 220 240 MN TX IN WI-A WI-B IA clay loam IA sand CA preplantemissionsON preplantemissionsON-NdelayedemissionsON sizeEffect 2 22 Relative to preplant N, variable-rate sidedress N application reduced growing season N2O flux by 69% in 2015, from 2.4 to 0.7 kg N ha-1. 0 0.5 1 1.5 2 2.5 3 2012 2013 2014 2015 4-Yr ave N2O emissions, kg N ha-1 year-1 sensor-based at V7 140 pre-plant Average N2O flux is 61% lower with variable-rate sidedress N application relative to preplant N. Delaying N application to V6 in single or split application is predicted to generally reduce N2O flux, but effect varies with weather and soil type. N2O flux is measured weekly from all plots during the growing season. In drained experiments, drainage water sampled for nitrate weekly. Measured Corn Grain Yield (gC . ha-1 +/- SD) 0 2000 4000 6000 8000 ModeledCornGrainYield(gC.ha-1) 0 2000 4000 6000 8000 n = 20 sites; r = 0.59 The model is calibrated to field data and an extensive regional database of N-rate experimental data. Future climate predictions are from regional downscaling of five global climate models. Stars are plots that received N at V7 all others received preplant. Later N application improved N status in late August 2015, but not yield. Over three years (‘12-’14), average N application at V7 was 99% of preplant N amount. Average yield with application at V7 was 12% higher while nitrate in drainage water was 24% lower than with preplant N application. (Data not shown). Whether split or delayed N application reduces N2O emissions may depend on soil type. Simulation reproduces experimental data and predicts importance of both form of N fertilizer and soil type in modulating impact of N timing on N2O flux. On average, split or delayed N application maintains yield while reducing nitrate and N2O losses. But not everywhere or every year.