Simulating the Impact of Management Practices on Nitrous Oxide Emissions
- C. Xu ,
- M. J. Shaffer and
- M. Al-kaisi
Effective evaluation of alternative management strategies to control global warming requires tools for simulating emissions of N2O from soils across a range of soil properties, weather, and management inputs. We hypothesized that with modification to the nitrification and denitrification submodels of the Nitrate Leaching and Economic Analysis Package (NLEAP) model, we could simulate daily N2O emissions as a function of soil moisture, temperature, N content, and other factors. Field parameterization was conducted on an Ulm clay loam soil (a fine, montmorillonitic, mesic Ustollic Haplargid) and validation experiments for N2O gas emissions were performed on an on-farm swine effluent study site on a Valent sandy soil (a mixed, mesic Ustic Torripsamment). The unitless model parameters reflecting the maximum fraction of selected N transformations emitted as N2O for nitrification (αN), wet-period denitrification (αw), and dry-period denitrifiation (αd) were calibrated as 0.065, 0.050, and 0.520 separately and then used in the validation study. The trends and magnitudes of simulated N2O emissions were statistically consistent with the results obtained from the field experiments (r = 0.78). Experimental results showed that the decline of N2O emission rates from 70 to 2 g N ha−1 d−1 during the growing season was related to soil N content decline from 33 to 4 mg kg−1. Simulated effects of field management on annual N2O emissions indicated that plowing decreased N2O relative to notillage corn (Zea mays L.), irrigation increased N2O 14% relative to dry-land corn, and doubling fertilization N rates from 100 to 200 kg ha−1 increased N2O emissions 60%.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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