【作者】 曾涛；

【导师】 吕国安； 陈家宙；

【作者基本信息】 华中农业大学 ， 土壤学， 2010， 硕士

【摘要】 我国红壤丘陵地区降水分配极不均匀和季节性干旱突出,由水蚀引起土壤入渗性能变化,在很大程度影响了季节性干旱的发展。研究不同水土保持措施下红壤的入渗性能,探讨土壤入渗性能变化对季节性干旱的影响,对选取合适的水土保持措施和干旱防御措施具有重要意义。以红壤丘陵坡地为研究对象,大田径流小区分别设置对照、百喜草带、稻草覆盖、表土施PAM(聚丙烯酰胺)、稻草覆盖+PAM、百喜草带+PAM等6个处理,在雨季和季节性干旱时期动态观测不同水蚀阻断处理的入渗率、入渗量、土壤水分剖面分布和土壤干旱程度。与此同时,在室内设置稻草覆盖、PAM、稻草覆盖+PAM等4个处理,通过土槽人工模拟降雨,研究不同降雨强度和初始含水量下红壤的入渗性能。所得到的主要研究结果如下：不同的水蚀状况会降低土壤的饱和入渗率。自然降雨量为74.3mm时,不同处理的饱和入渗率的下降幅度为3.21%～17.88%；自然降雨量达到102.8mm时,饱和入渗率下降幅度为76.58%～88.11%,小区不同水蚀阻断处理的饱和入渗率在雨后均高于对照处理。土壤的饱和入渗率与土壤干旱程度有很好的负相关关系,随着水蚀土壤饱和入渗率降低会加剧土壤干旱程度。不同的水蚀阻断措施能增强入渗性能。在不同的降雨强度(60mm/h、90mm/h)和不同的初始含水量(0.08cm3·cm-3、0.15 cm3·cm-3、0.25 cm3·cm-3)下,稻草覆盖和PAM等不同水蚀阻止处理,与对照相比,均能延缓地表产流时间,增加入渗速率,提高土壤的入渗量。在雨季和旱季的不同降雨量下,不同水蚀阻断处理均能增加土壤的入渗量,提高土壤不同层次的含水量。通过对土壤旱季入渗量和土壤干旱程度的相关性分析,入渗量与土壤干旱呈现显著的负相关关系。土壤入渗性能变化对土壤干旱的影响程度不同。从土壤持续干旱的过程中的干旱程度D值可以看出,在干旱初期,不同水蚀阻断措施的干旱程度D值均小于对照,在连续干旱了较长时间后,水蚀阻控措施的处理(稻草覆盖和稻草覆盖+PAM)干旱程度仍然小于对照。通过对入渗率、旱季入渗量与干旱程度度进行相关分析,得到与土壤干旱状况的相关性从大到小的顺序为：入渗量>饱和入渗率>非饱和入渗率,其中,入渗量与土壤干旱程度成显著负相关。更多还原

【Abstract】 In the red soil hilly region of china,the section rainfall distributing odds and the seasonal drought are very prominent, the change of soil infiltration performance caused by the water erosion, has affected the seasonal drought development in the very great degree.Under the different conservation of water and soil measure, studies the infiltration on the red soil hilly region and discuss the change of soil infiltration to the influence of seasonal drought, to select the appropriate conservation of water and soil measurement and the drought defensive measure has the important influence.The research area was established on slope field of Red Soil. Six treatments (Straw mulch, PAM, Contour hedgerow and combination) were tested in a randomized complete block design on the cultivated plots with maize.the infiltration rate, the infiltration quantity, Soil moisture distribution and soil drought degree (D) were were monitored in different conservation of water and soil measure during erosion and seasonal drought period. Meanwhile, soil column experiments with straw mulch and PAM were used to investigate the red soil water infiltration process with soil column experiments in different rainfall intensity and different antecedent soil moisture contents in laboratory, through earth trough manual simulation rainfall. These research results are as followed:The different water erosion condition will reduce the soil the saturated infiltration rate.When the natural rainfall amount is 74.3mm, the saturated infiltration rate’s of different measurement decline rate is 3.21%～17.88%;When the natural rainfall amount achieves 102.8mm,the saturated infiltration rate decline rate is 76.58%～88.11%,The the saturated infiltration rate of different water erosion blocks processing is higher than comparison in the plot after the rain. The soil saturated infiltration rate and the soil drought degree have the very good inverse correlation relations, with the saturated infiltration rate of soil reduced, the water erosion will intensify the soil drought degree.The different conservation measurement of water and soil would be able to strengthen the performance of infiltration. The straw mulch cover and PAM treatments, compares with the comparison, can delay the runoff start time, increased the infiltration rate, enhanced the soil the infiltration quantity in different rainfall intensity(60mm/h、90mm/h)and different antecedent soil moisture contents (0.08cm3·cm-3、0.15 cm3·cm-3、0.25 cm3·cm-3) With different rainfall in the rainy and dry season, the different treatments be able to increase the soil the infiltration quantity, enhances the the water content indifferent soil level. Through to the soil dry season infiltration quantity and the soil drought degree’s relevant analysis, the infiltration quantity and the soil drought degree presents the remarkable inverse correlation relations.The change of soil infiltration capability has different influence in the soil drought degree.the soil drought degree D value in the continuing drought process can be seen, in the initial drought period, thedrought degree D value of different treatments is smaller than the comparison, after long time by continuously drought, the drought degree of the treatments (straw cover and straw covers+PAM) was still smaller than the comparison. Through the infiltration rate, the soil dry season infiltration quantity and the arid degree the correlation analysis, the correlation of soil drought conditions in sequence:Infiltration amount>saturated infiltration rate >unsaturated infiltration rate,among them, soil infiltration have a significant negative correlation in drought degree.更多还原