土壤容重对黑土坡面养分流失的影响

发布时间：2018-06-15 03:09

本文选题：土壤容重 + 模拟降雨　；参考：《水土保持学报》2016年01期

【摘要】：为深入了解土壤容重对黑土区坡面养分流失的影响,在沈阳农业大学水利试验基地,采用室内人工模拟天然降雨的方法,对不同容重条件下的黑土坡面养分流失进行研究。试验结果表明:土壤容重是影响坡地溶质迁移以及坡面降雨产流产沙的重要因素。土壤容重在0.8~1.3g/cm~3间变化时,随泥沙流失的养分与径流水样中养分的流失呈现出相似规律。随着容重增大,径流系数变大,产流时间提早,入渗率减小,溶质(N、P、K)的流失量增加。在产流初期,径流强度增加显著,径流硝态氮衰减速率快,10min内基本达到本底值,同一时段径流水样中PO_4~(3-)-P和K~+浓度升高,而产流后期,溶质浓度含量由于土壤发生面蚀甚至沟蚀而随容重呈相反变化。土层湿润锋深度随容重增大而变浅,容重为0.8g/cm~3时,湿润锋可达15cm,容重为1.4g/cm~3时,仅淋失到地表11cm深处,且表层土壤容重对硝态氮在土层中流失的影响大于对速效磷和速效钾流失的影响。当容重增大至1.4g/cm~3时,土壤结构坚实,养分浓度有所降低,流失量小,土壤流失情况减弱,说明采用适当的耕作措施改变表层容重可有效控制土壤侵蚀的发生。通过数学模拟分析,也进一步证实了幂函数是较为适于模拟黑土区溶质流失变化过程的模型。
[Abstract]:In order to understand the effect of soil bulk density on nutrient loss of slope in black soil area, the nutrient loss of black soil slope under different bulk density was studied in Shenyang Agricultural University water conservancy test base by artificial simulation of natural rainfall. The results show that soil bulk density is an important factor affecting solute migration and precipitation and sediment yield on slope. When the bulk density of soil varies between 0.8~1.3g/cm~3, the nutrient loss with sediment is similar to the nutrient loss in runoff water. With the increase of bulk density, the runoff coefficient becomes larger, the runoff time is earlier, the infiltration rate decreases, and the loss of solute N (P) K) increases. In the early stage of runoff production, the intensity of runoff increased significantly, and the attenuation rate of nitrate nitrogen in runoff almost reached the background value within 10 minutes. In the same period, the concentrations of PO4 and K- P in runoff samples increased, while in the late stage of runoff, the concentration of PO4 + -P and K- P increased. The concentration of solute changed with the bulk density because of soil surface erosion and even furrow erosion. The depth of soil wetting front becomes shallow with the increase of bulk density. When the bulk density is 0.8g / cm ~ 3, the wet front can reach 15 cm, and the bulk density is 1.4 g / cm ~ 3. The effect of bulk density of surface soil on the loss of nitrate nitrogen in soil layer was greater than that on available phosphorus and potassium loss. When the bulk density increased to 1.4 g / cm ~ 3, the soil structure was solid, the nutrient concentration was decreased, the loss of soil was small, and the soil loss was weakened, which indicated that soil erosion could be effectively controlled by using appropriate tillage measures to change the surface bulk density. Through mathematical simulation and analysis, it is further proved that power function is a more suitable model for simulating the process of solute loss in black soil area.
【作者单位】：沈阳农业大学水利学院;
【基金】：辽宁省自然科学基金项目(20102197)
【分类号】：S152.5;S157

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