Testing DAYCENT model simulations of corn yields and nitrous oxide emissions in irrigated tillage systems in Colorado
Testing DAYCENT model simulations of corn yields and nitrous oxide emissions in irrigated tillage systems in Colorado
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DOI：
10.2134/jeq2007.0292
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发表时间：
2008-07-01
影响因子：
2.4
通讯作者：
Parton, W. J.
中科院分区：
文献类型：
--
作者：
Del Grosso, S. J.;Halvorson, A. D.;Parton, W. J.
农业土壤是美国一氧化二氮（N2 O）排放的主要来源。灌溉作物，特别是在美国西部，是N2 O排放的一个重要来源。然而，耕作强度和氮肥的数量和类型的影响还没有得到广泛的研究灌溉系统。DAYCENT土壤地球化学模型使用N2 O、作物产量、土壤N和C以及2002年至2006年期间从科罗拉多东北部灌溉种植系统收集的其他数据进行了测试。DAYCENT使用每日天气、土壤质地和土地管理信息来模拟大气、土壤和植被之间的C和N通量。模型的性质反映了耕作强度和氮肥用量对作物产量、土壤有机碳和土壤含水量的影响。DAYCENT N2 O排放量与实测数据相匹配，模拟排放量随着氮肥施用率的增加而增加，免耕（NT）的排放量平均低于常规耕作（CT）。然而，该模型高估了N2 O排放量。降低单位氮硝化的N2 O排放量从2%到1%有助于提高模型拟合，但不接受氮肥的处理仍然高估了2倍以上。模型和测量结果都表明，土壤NO3-水平增加与N肥的添加和耕作强度，但DAYCENT低估NO3-水平，特别是对于接受没有N肥的治疗。我们认为，DAYCENT可以通过降低背景硝化速率和占反硝化速率的微生物群落结构的变化的影响来改善。
Agricultural soils are responsible for the majority of nitrous oxide (N2O) emissions in the USA. Irrigated cropping, particularly in the western USA, is an important source of N2O emissions. However, the impacts of tillage intensity and N fertilizer amount and type have not been extensively studied for irrigated systems. The DAYCENT biogeochemical model was tested using N2O, crop yield, soil N and C, and other data collected from irrigated cropping systems in northeastern Colorado during 2002 to 2006. DAYCENT uses daily weather, soil texture, and land management information to simulate C and N fluxes between the atmosphere, soil, and vegetation. The model property represented the impacts of tillage intensity and N fertilizer amount on crop yields, soil organic C (SOC), and soil water content. DAYCENT N2O emissions matched the measured data in that simulated emissions increased as N fertilization rates increased and emissions from no-till (NT) tended to be lower on average than conventional-till (CT). However, the model overestimated N2O emissions. Lowering the amount of N2O emitted per unit of N nitrified from 2 to 1% helped improve model fit but the treatments receiving no N fertilizer were still overestimated by more than a factor of 2. Both the model and measurements showed that soil NO3- levels increase with N fertilizer addition and with tillage intensity, but DAYCENT underestimated NO3- levels, particularly for the treatments receiving no N fertilizer. We suggest that DAYCENT could be improved by reducing the background nitrification rate and by accounting for the impact of changes in microbial community structure on denitrification rates.