Abstract:

To find out the dynamic changes of soil moisture in the dry farming areas of Qinghai and to ensure the formation of crop yields and grain production safety, we studied the seasonal dynamics and vertical profile characteristics of soil moisture, and its responses to precipitation under different land use patterns in the shallow dry-land of Huzhu, Qinghai. The results showed that: (1) the soil moisture content of the tillage layer (0-30 cm) under different land use patterns had obviously dry-wet cycle changes, the land use pattern had no significant effect on the seasonal variation of soil moisture (P>0.05), but the precipitation events and precipitation levels were the dominant driving forces affecting the seasonal dynamics of soil moisture content in the tillage layer (0-30 cm); (2) 0-30 cm soil layer was the rain-fed layer, its soil moisture seasonal dynamics could be divided into dry period, wet period, normal period and transition period; the occurrence of soil drought generally began with the surface layer and gradually extended to the deep soil with the increase of the soil moisture loss; (3) the soil moisture dynamics of 4 land use types were basically consistent with the changes of the previous precipitation, and the soil water content of the subsurface (10-20 cm) and the deep (20-30 cm) were significantly correlated with the cumulative precipitation in the previous period (P<0.01). Therefore, the “shallow buried drip irrigation technology” is an effective way to seek the balance of soil water supply in the dry farming area of Qinghai with frequent drought events.

Key words: land use pattern, soil water content, drought, precipitation response, shallow mountain area of Huzhu, seasonal change, tillage layer