Model Simulation Research of Soil Organic Carbon Dynamics of Long-Term Conservation Tillage in Black Soil
[Objective]Conservation tillage is an important measure for restoring and enhancing soil fertility,and soil organic carbon(SOC)plays a crucial role in maintaining soil fertility,supporting crop growth,and protecting soil environment.However,there is currently a lack of long-term monitoring platforms for conservation tillage in China,so using modeling methods can help study SOC dynamics under long-term conservation tillage.[Method]A long-term tillage experiment was established in the black soil region in 2001 with three treatments:no-tillage(NT),moldboard plow(MP),and ridge-tillage(RT).The structures and parameters of process-based models(RothC,AMG model)and statistical models(MLPNN model)were optimized.The changes in SOC under long-term conservation tillage were simulated and compared.The effectiveness of different models in simulating and predicting the SOC dynamics under conservation tillage was evaluated,and the long-term response and influencing factors of SOC in black soil in Northeast China to conservation tillage were revealed.[Result]After optimizing parameters for carbon pool allocation,errors of the RothC and AMG models were significantly reduced.During the first 11 years(2001-2012)of conservation tillage,there was no significant difference in the simulation of SOC between RothC and AMG models,indicating that the structural complexity of process models does not have significant impacts on the simulation results for relatively short term.The simulation results of the statistical model MLPNN were similar to process models,proving the application of statistical models in small-scale regions.Over the next 100 years,RothC and AMG models predicted similar trends in SOC changes,but AMG model significantly overestimated the increase in SOC stocks,which may be attributed to SOC saturation and the influence of tillage practices.Both RothC and AMG models showed high sensitivity to carbon input,but they responded differently to climate and soil factor changes.[Conclusion]It is necessary to choose appropriate models based on local conditions while using models to simulate SOC in long-term conservation tillage.For short-term prediction of SOC under conservation tillage,a relatively simple AMG modelcan be used,while for long-term prediction,a more complex RothC model can be used.Under specific conditions,statistical models show similar effects to process models in simulating soil organic carbon at a small-scale regions,such as plots and fields.
soil organic carbonconservation tillagemodel simulationblack soilprocess-based modelstatistical modelNortheast China
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