Biochar application as a tool to decrease soil nitrogen losses ( NH 3 volatilization, N 2 O emissions, and N leaching) from croplands: Options and mitigation strength in a global perspective

作者：Qi Liu, Benjuan Liu, Yanhui Zhang, Tianlong Hu, Zhibin Lin, Gang Liu, Xiaojie Wang, Jing Ma, Hui Wang, Haiyang Jin, Per Ambus, James E. Amonette, Zubin Xie · 发表于：Global Change Biology · 年份：2019 · DOI：10.1111/gcb.14613 · 被引用次数：249 · 研究领域：Soil Carbon and Nitrogen Dynamics、Phosphorus and nutrient management、Ammonia Synthesis and Nitrogen Reduction

Abstract Biochar application to croplands has been proposed as a potential strategy to decrease losses of soil‐reactive nitrogen (N) to the air and water. However, the extent and spatial variability of biochar function at the global level are still unclear. Using Random Forest regression modelling of machine learning based on data compiled from the literature, we mapped the impacts of different biochar types (derived from wood, straw, or manure), and their interactions with biochar application rates, soil properties, and environmental factors, on soil N losses ( NH 3 volatilization, N 2 O emissions, and N leaching) and crop productivity. The results show that a suitable distribution of biochar across global croplands (i.e., one application of <40 t ha −1 wood biochar for poorly buffered soils, such as those characterized by soil pH <5, organic carbon<1%, or clay>30%; and one application of <80 t ha −1 wood biochar, <40 t ha −1 straw biochar, or <10 t ha −1 manure biochar for other soils) could achieve an increase in global crop yields by 222–766 Tg yr −1 (4%–16% increase), a mitigation of cropland N 2 O emissions by 0.19–0.88 Tg N yr −1 (6%–30% decrease), a decline of cropland N leaching by 3.9–9.2 Tg N yr −1 (12%–29% decrease), but also a fluctuation of cropland NH 3 volatilization by −1.9–4.7 Tg N yr −1 (−12%–31% change). The decreased sum of the three major reactive N losses amount to 1.7–9.4 Tg N yr −1 , which corresponds to 3%–14% of the global cropl...