Helmholtz Centre for Environmental Research (UFZ), Department of Soil Physics, Theodor-Lieser-Straße 4, 06120, Halle/Saale, Germany; Helmholtz Centre for Environmental Research (UFZ), Department of Computational Landscape Ecology, Permoserstraße 15, 04318, Leipzig, Germany.
Gesellschaft für Angewandte Landschaftsforschung (GALF) bR, Am Ende 14, 01277, Dresden, Germany.
J Environ Manage. 2019 May 1;237:272-280. doi: 10.1016/j.jenvman.2019.02.036. Epub 2019 Feb 22.
Changes in land-use, agricultural management and climate affect the turnover and storage of organic carbon in soils (SOC) as well as the nitrogen mobilization from soil organic matter (SOM), with potential side effects on nitrogen availability and leaching. When addressing the requests for increased carbon storage in soil as well as for the reduction of nitrogen losses, integrated approaches on regional scales are required that take into account the actual changes in agricultural management and climate. This study investigated the arable land (7345 km) of Saxony (Germany) with regard to the following: (1) the trends of SOC storage and organic matter-related nitrogen fluxes, including their subregional and annual dynamics, (2) changes in the carbon input to arable soils and the turnover of organic matter, and (3) the contribution of different drivers (climate, crop production and fertilization, tillage system) to the simulated SOM changes for the period 1998-2014 on a 500 m grid. The model CANDY carbon balance (CCB) was specifically adapted for large-scale simulations of SOM turnover to link spatial data on soils and climate with regional statistics on agricultural management. This new 'regional mode' of CCB has been validated using data from 391 plots across different European locations. The initial SOC levels for Saxony assumed steady state conditions at the beginning of the simulation period and have been validated using data from 667 monitoring sites. The results showed an increase in the SOC stocks of the arable soils of Saxony of 785 × 10 t C (1.24‰ annually) during the simulation period. At the same time, the model simulated an average increase in organic nitrogen stored in SOM of approximately 7.5 kg N ha a, with considerable differences between individual years and subregions. Both the increase in carbon inputs to soil (+8%) and the reduction of carbon turnover rates (-10%) had positive effects on SOC storage. While the increased use of conservation tillage was the most important driver for the overall increase in SOM storage in Saxony, climate variability and crop production and fertilization had the largest effect on its annual dynamics.
土地利用、农业管理和气候的变化会影响土壤有机碳（SOC）的周转和储存，以及土壤有机质（SOM）中氮的释放，这可能会对氮素有效性和淋失产生潜在的副作用。在满足增加土壤碳储存和减少氮素损失的要求时，需要在区域尺度上采取综合方法，同时考虑到农业管理和气候的实际变化。本研究以德国萨克森州的耕地（7345 平方公里）为对象，调查了以下方面：（1）SOC 储量和与有机质相关的氮通量的趋势，包括其亚区域和年度动态；（2）耕地土壤碳输入和有机质周转的变化；（3）不同驱动因素（气候、作物生产和施肥、耕作制度）对 1998-2014 年期间模拟 SOM 变化的贡献，采用 500m 网格的空间数据与农业管理的区域统计数据相结合，专门对 CANDY 碳平衡（CCB）模型进行了调整，以用于大规模模拟 SOM 周转。新的“区域模式”的 CCB 已经通过来自不同欧洲地点的 391 个地块的数据进行了验证。萨克森州的初始 SOC 水平假设在模拟期开始时处于稳定状态，并使用来自 667 个监测点的数据进行了验证。结果表明，在模拟期间，萨克森州耕地土壤的 SOC 储量增加了 785×10tC（年增长率为 1.24‰）。同时，模型模拟出 SOM 中储存的有机氮平均增加了约 7.5kgNha-1，个别年份和亚区之间存在相当大的差异。土壤碳输入的增加（+8%）和碳周转速率的降低（-10%）对 SOC 储存都有积极影响。虽然保护性耕作的增加是萨克森州 SOM 储存总体增加的最重要驱动因素，但气候变率以及作物生产和施肥对其年度动态的影响最大。
