黑土区土壤养分径流迁移物理过程解析与模型研究

Serious soil erosion and nutrient loss which direct threat tonational strategies for food security in the black soil region of Northeast China. The other research findings cannot be simply borrowed and applied directly due to the unique characteristics of rainfall and near-surface soil hydrological conditions. This project carry out indoor artifical simulating rainfall experiments and outdoor in situ monitoring nutrient loss with runoff experimrnts base on the black soil area rainfall characteristics, near-surface soil hydrological conditions and unsubstantial study of nutrient loss vie runoff in the black soil region of Northeast China. Put up the theoretical analysis with the test results,reveal the effection on black soil nutrient transport vie runoff of main factors: rainfall intensity, slope gradient, near-surface soil hydrological conditions, initial soil water content, ground cover and vegetation type. Provide a new approach to determine the parameters for typical soil nutrients nitrogen, phosphorus and potassium in the black soil region. According to the soil nutrient and water interaction, establish soil nutrient vertical, horizontal transfer mechanism model and surface runoff model, Find out the interactive relationship between soil nutrient transport with interflow and surface runoff. Develop soil nutrient transport mechanism model with mix together interflow and surface runoff in the black soil region of Northeast China.Enrich and perfect nutrient loss with runoff in the black soil region of Northeast China. The theoretical results are helpful to the grain production and ecological construction in the black soil region of Northeast China

我国东北黑土区土壤侵蚀及养分流失直接威胁到国家的粮食战略安全，由于黑土区独特的降雨特征和近地表土壤水文条件，不能简单借鉴和应用世界其它地区的研究成果。本研究针对我国黑土区径流养分流失研究相对薄弱的现状，基于黑土区降雨特征和近地表土壤水文条件进行室内人工模拟降雨和野外原位监测试验研究，结合试验结果进行理论分析。揭示径流养分迁移主要影响因素：降雨强度、坡面坡度、近地表土壤水文条件、土壤初始含水量、地面覆盖度和植被类型对黑土区养分径流迁移的作用机理。提出黑土区典型土壤养分氮、磷和钾迁移参数确定方法。根据土壤养分与水分互作效应，建立土壤养分垂直、水平迁移机理模型和地表径流迁移机理模型，明确土壤养分随壤中流和地表径流迁移的交互关系，建立黑土区土壤养分融合壤中流与地表径流的径流迁移机理模型。丰富、完善我国黑土区径流养分流失规律研究。其理论成果有助于我国东北黑土区粮食生产和生态建设的健康发展。

本研究针对我国黑土区径流养分流失研究相对薄弱的现状，基于黑土区降雨特征和近地表土壤水文条件进行室内人工模拟降雨和野外原位监测试验，结合试验结果进行理论分析。揭示径流养分迁移主要影响因素：降雨强度、坡面坡度、近地表土壤水文条件、土壤初始含水量、地面覆盖度和植被类型对黑土区养分径流迁移的作用机理。提出黑土区典型土壤养分氮、磷和钾迁移参数确定方法。根据土壤养分与水分互作效应，建立土壤养分垂直、水平迁移机理模型和地表径流迁移机理模型，明确土壤养分随壤中流和地表径流迁移的交互关系，建立黑土区土壤养分融合壤中流与地表径流的径流迁移机理模型。结果显示。初始含水量通过影响入渗来影响养分径流流失，初始含水量高径流养分浓度高。降雨强度越大，径流养分浓度越高，表层土壤养分含量高，在降雨和径流影响下，有更多养分进入径流。研究区壤土的临界坡面坡度介于10º至15º之间。犁底层、土壤孔隙度、适度干旱均是造成大豆根系补偿性生长的原因。研究区单次降雨湿润峰普遍位于犁底层之上，未触及犁底层。线性方程可以准确反映0-15cm土层土壤饱和导水率的变化规律。土壤养分迁移依赖于土壤水分的迁移，土壤水分迁移参数决定了养分的迁移参数。基于以上实验结果，构建了研究区犁底层以上饱和导水率垂向变异方程。研究区降雨强度小于16.8mm/h时，犁底层以上土壤总含水量超过49.7mm才可能产生壤中流。降雨强度大于16.8mm/h时，可以近似认为湿润峰到达犁底层处且含水量等于田间持水量时土壤水分剖面形状相同，即每次大雨强降雨时，产生壤中流时刻土壤剖面含水量相同，据此得到了研究区壤中流产流时刻土壤剖面含水量分布图，同时可计算出壤中流产生时刻。建立了基于混合层理论的土壤养分垂直、水平迁移机理模型和地表径流迁移机理模型。丰富、完善了我国黑土区径流养分流失规律研究。其理论成果有助于我国东北黑土区粮食生产和生态建设的健康发展。