Aarhus University, Department of Agroecology, Blichers Allé 20, P.O. Box 50, DK-8830 Tjele, Denmark.
Environ Pollut. 2011 Nov;159(11):3183-92. doi: 10.1016/j.envpol.2011.02.043. Epub 2011 Mar 31.
The aim of this study is to illustrate the importance of farm scale heterogeneity on nitrogen (N) losses in agricultural landscapes. Results are exemplified with a chain of N models calculating farm-N balances and distributing the N-surplus to N-losses (volatilisation, denitrification, leaching) and soil-N accumulation/release in a Danish landscape. Possible non-linearities in upscaling are assessed by comparing average model results based on (i) individual farm level calculations and (ii) averaged inputs at landscape level. Effects of the non-linearities that appear when scaling up from farm to landscape are demonstrated. Especially in relation to ammonia losses the non-linearity between livestock density and N-loss is significant (p > 0.999), with around 20-30% difference compared to a scaling procedure not taking this non-linearity into account. A significant effect of farm type on soil N accumulation (p > 0.95) was also identified and needs to be included when modelling landscape level N-fluxes and greenhouse gas emissions.
本研究旨在阐明农田尺度异质性对农业景观中氮（N）损失的重要性。研究结果以一系列氮模型为例，这些模型计算了农场氮平衡，并将氮盈余分配到氮损失（挥发、反硝化、淋失）和土壤氮积累/释放中，研究范围为丹麦景观。通过比较基于（i）单个农场水平计算和（ii）景观水平平均投入的平均模型结果，评估了上推到景观水平时的可能非线性。展示了当从农场尺度上推到景观尺度时出现的非线性效应。特别是在氨损失方面，牲畜密度和 N 损失之间的非线性关系非常显著（p>0.999），与不考虑这种非线性关系的上推过程相比，差异约为 20-30%。还确定了农场类型对土壤 N 积累的显著影响（p>0.95），因此在模拟景观水平氮通量和温室气体排放时需要将其纳入考虑。
