用RothC-26.3模型模拟玉米连作下长期施肥对黑土有机碳的影响

 用RothC (Version 2 6 .3)模型模拟研究东北地区黑土长期定位施肥试验中玉米连作下土壤有机碳 (SOC)含量的变化。从 2 4个施肥处理中选取了无肥 (对照 )、氮肥、氮肥配施厩肥、氮磷钾肥配施、厩肥 5个处理 ,对耕层土壤SOC的模拟值与实际测定值进行了比较。模型预测值与实测值之间吻合较好 ,说明RothC模型可以很好的用来模拟东北温带气候区现有耕作管理条件下黑土SOC的动态变化。结果表明 ,在当前常规耕作秸秆不还田条件下 ,整个试验期间不施肥 ,SOC含量持续下降 ;单施氮或施氮磷钾不能维持耕层 (2 0cm)SOC含量 ;厩肥配合施用化肥 ,则会增加SOC含量。保持这种管理方式不变 ,SOC将持续下降至新的平衡点。模拟结果表明 ,如果实施秸秆还田 ,到 2 0 2 2年时无肥、氮肥、氮磷钾肥、氮肥配施厩肥和氮磷钾配施厩肥等处理区的SOC较 2 0 0 2年将分别增加 2 6 %、4 0 %、4 5 %、38%和 4 6 %。RothC模型可用来评价不同管理方式下黑土SOC变化趋势 ,秸秆还田将显著增加研究区黑土的SOC含量

RothC-26.3 Model Simulating Long-term Effects of Fertilization on Changes of Soil Organic Carbon in Continuous Cultivation of Corn in Northeast China

RothC model (Version 26.3) was used to estimate soil organic C (SOC) levels under continuous cultivation of corn in a long-term fertilization trail in the Songnen Plain, Northeast China. We compared the model output for the changes in SOC with those measured from a Black soil (Typic Halpudoll) at Gongzhuling, Jilin Province, from the control (no-fertilization) vs. fertilized with N or NPK with/without manure addition. The sound performance of model in simulating SOC changes suggests that RothC is feasible for Black soils in the temperate climatic region of Northeast China. The modeled and measured results indicated that no-fertilization treatment led to a continuous decline of SOC during the study period and N and NPK fertilization were inadequate to maintain the SOC level in the plow layer (upper 20-cm) unless FYM was added, associating with the current conventional management with no aboveground crop residues returning into the soil. Soil organic carbon could follow the same path of decline if the same management practices maintained. Model results indicate that returning the above-ground crop residues into the soil from 2002 to 2022 increased SOC by 26% in the no-fertilization treatment, 40% in N treatment, 45% in the NPK treatment, and 38% and 46% in the N and NPK with FYM addition treatments, compared to the levels in the corresponding treatments in 2002. The simulation results suggest that the RothC model is a feasible tool to assess SOC trend under different management practices and returning the aboveground crop residues into the soil will lead to a remarkable increase in SOC in the region.