Soil Moisture of Leucaena leucocephala Plantations in the Dry-hot Valley of Jinsha River,Yunnan

Key words: 
• Soil moisture /
• precipitation /
• vertical change /
• soil mechanical composition /
• soil organic matter

Abstract: Soil moisture is known to have a major impact on the physiological activities of plants,and is the main water source for plants.The soil moisture content of Leucaena leucocephala plantations or artificial forests in the dry-hot valley of Jinsha River was observed to analyze its temporal and spatial dynamic changes and influencing factors in the plantations.The results showed that the soil moisture content of L.leucocephala plantations was higher during the wet season and lower during the dry season.The soil moisture was increased with the soil depth,and its change was greater in the upper layer of the soil than in the lower layer of the soil.The annual changes of the soil moisture content increased with the rainfall,but there existed a hysteresis effect between the soil moisture content and the rainfall.L.leucocephala plantations effectively reduced the transpiration of moisture in the 0-40 cm soil layer during the wet season and hence had a good water conservation function.The L.leucocephala plantations gave great impact to the physical and chemical properties of the soil by reducing soil bulk density and increasing soil porosity and soil organic matter content,which produced positive effect on the capability of water holding and conservation.The soil sand content of L.leucocephala plantations was significantly positively correlated with the soil moisture content（P＜0.05）,but significantly negatively with the silt content and the clay content（P＜0.05）.Therefore,rational development of L.leucocephala plantations in the dry-hot Valley of Jinsha River can effectively improve the physical and chemical properties of the soil,and the water retention and conservation of the soil,and hence have an ecological function of soil and water conservation.