滨海盐渍土地区水稻田C、N及生物量动态变化的模拟与应用

Simulation of C,N and biomass dynamic change in coastal saline soil region paddy field

滨海盐渍土地区耕地的有机碳(SOC)、氮(N)及生物量演变是反映该区域土壤质量的重要内容。借助DNDC(Denitrification—Decomposition)模型模拟江苏滨海滩涂地区盐渍土水稻田土壤有机碳(SOC)、铵态氮(NH_4^+-N)、硝态氮(NO_3~–-N)和生物量的变化过程,分析DNDC模型在江苏滨海盐渍土垦区土壤的适用性,并对DNDC模型模拟结果进行验证。结果表明:DNDC模型在滨海地区水稻田对生物量、土壤有机碳和氮的模拟结果良好;土壤有机碳均方根误差(RMSE)为0.069,土壤铵态氮RMSE为11.1,硝态氮RMSE为0.28,总生物量RMSE为397.92;滨海盐渍土土壤有机碳和作物产量模拟精度较高(RMSE<10%),铵态氮和硝态氮模拟精度较好(RMSE<20%);模型能正确反映土壤有机碳、硝态氮、铵态氮在水稻生长过程中的变化规律,同时能很好地揭示施肥与氮素含量、硝态氮与土壤水之间以及铵态氮和硝态氮含量上的相互关系。

The soil organic carbon （SOC）, nitrogen （N） and biomass evolution are three significant factors in the coastal reclamation area, eastern China. Simulating paddy field C, N and biomass dynamic change though DNDC model in study area can reflect soil biogeochemical process and test model accuracy in saline soil. The results are as follows. （1） The RMSE of SOC was 0.069, ammonium nitrogen （NH4＋-N） was 11.1, nitrate nitrogen （NO– 3 -N） was 0.28 and rice biomass was 397.92.（2） SOC and rice biomass simulation accuracy was the highest （RMSE 〈10%）, and N simulation accuracy was higher （RMSE 〈20%）. （3） DNDC model could not only reflect SOC, N and biomass change correctly in rice growth period, but also reveal the relationships between fertilization and nitrogen content, nitrate nitrogen （NO– 3 -N） and soil water, ammonium nitrogen （NH4＋-N） and nitrate nitrogen （NO– 3 -N） content.