[Dynamic changes of soil moisture in loess hilly and gully region under effects of different yearly precipitation patterns].
Based on field determinations, the dynamic changes of soil moisture in dry farmland, Robinia pseudoacacia forestland, Hippophae shrubland and Bothriochloa ischaemum grassland in loess hilly and gully region under effects of different yearly precipitation patterns were analyzed. The results showed that yearly precipitation pattern had definite effects on the seasonal variation and profile distribution of soil moisture. In normal year, soil moisture in dry farmland had a gentle seasonal variation; in dry year, it decreased slowly before rainy season but increased markedly after rainy season; while in rainy year, it had an overall increase and the increment was remarkable after rainy season. The soil moisture in R. psendoacacia forestland, Hippophae shrubland, and B. ischaemun grassland decreased as a whole in normal year. In dry year, soil moisture in Hippophae shrubland decreased first and increased then, while that in R. psendoacacia forestland and B. ischaemun grassland varied in "W" type, with the minimum in June and August. In rainy year, the seasonal variation of soil moisture in R. psendoacacia forestland and Hippophae shrubland presented "V" type, and that in B. ischaemu grassland fluctuated markedly, with the minimum in August. In dry farmland, the active and sub-active layers of soil moisture were deeper in dry year than in normal year, and the sub-active layer disappeared in rainy year. In R. psendoacacia forestland and B. ischaemu grassland, the active layer of soil moisture was deeper in dry and rainy years than in normal year; while in Hippophae shrubland, this active layer was shallower in dry and rainy years than in normal year.
Zhang
Bei-Ying
BY
Institute of Soil and Water Conservation, Chinese Academy of Sciences & Ministry of Water Resources, Yangling 712100, Shaanxi, China. zhangbeiying@163.com
Xu
Xue-Xuan
XX
Liu
Wen-Zhao
WZ
Chen
Tian-Lin
TL
D002681:China; D003889:Desert Climate; D017753:Ecosystem; D006109:Poaceae / Q000254:growth & development; D011891:Rain; D012987:Soil / Q000032:analysis*; D014197:Trees / Q000254:growth & development; D014867:Water / Q000378:metabolism; D014872:Water Movements
D012987:Soil; D014867:Water