Effects of Land Management Practices on Soil Water in Southwestern Mountainous Area, China

The effects of selected land management practices (cross-sloping tillage, ridge culture, organic manure, and straw mulch)on soil water conservation in a southwestern mountainous area, China, were studied during November 2002 to November2004. The experimental field is divided into three parts based on soil layer depths, 0-60 cm (part I), 0-40 cm (part II), and 0-20 cm (part III), and they all had the same slope azimuth (SE), slope (10o), and slope type (linear). The experimental plotswere subjected to the following treatments: cross-sloping tillage (CST); cross-sloping tillage with organic manure (CST/OM); cross-sloping tillage with straw mulch (CST/SM); contour ridge culture (CRC); contour ridge culture with organicmanure (CRC/OM); and contour ridge culture with straw mulch (CRC/SM), to identify the effects of management practiceson soil water. Water contents were determined for soil samples collected, using a 2.2 cm diameter manual probe. Soil waterwas monitored once every five days from Nov. 20, 2002 to Nov. 20, 2004. The results indicated that, in the study stages,an integration of rainfall, evaporative losses, and crop transcription controlled the basic tendencies of profile (mean) soilwater, while land management practices, to a certain extent, only modified its amount, distribution, and routing. Moreover,these modifications also mainly focused on the first 20 cm depth of topsoil layer. When each management practice wascompared with control treatment, season changes of profile (mean) soil water were pronounced, while interannual changesamong them were not significant. More comparisons indicated that, in the study stages, contour ridge culture had bettereffects than cross-sloping tillage. And under the same tillage, the combination of organic manure could achieve more thanstraw mulch. These management practices should be recommended considering the effectiveness of soil and watermanagement techniques in the southwestern mountainous area, China.