Study of impacts of land uses on spatiotemporal dynamics of soil water content ( SWC) is
of great significance for understanding the performance characteristics of regional water cycling under
changing environment． Based on long-term located field observations，this paper explored the
temporal dynamics of soil water in 0－15 m soil profile under four land use types on the Loess Tableland
from September 2012 to December 2015． Ｒesults showed that the annually averaged SWCs over
the 0－15 m soil profile for alfalfa field，fallow field，fertilized cropland and unfertilized cropland
were 15．1%，22．0%，19．6% and 21．1%，respectively． Soil water contents along the shallow soil
profile exhibited seasonal and annual wetting and drying cycle from March to June and July to October，
and the profile depths were 0－2，0－4．6，0－3 and 0－4．2 m，respectively． Soil water contents
along the deep soil profiles had better temporal stability and were influenced by land-use types． During
the observation years，the yield and water consumption in alfalfa field increased，which caused
the increase of deep soil desiccation，the 2－10 m soil profile had become stable dry layer，blockingthe way of precipitation recharge． As for the soil water balance in other three land use types，it was
negative in cropland and fallow field during winter wheat growing season，however，during spring
maize growing season，it was negative in fertilized cropland but positive in unfertilized cropland and
fallow field． During the fallow period，it was positive in the three land use types． The crop water use
efficiency in the fertilized cropland was increased by more than 3 times than the unfertilized cropland．
修改评论