5. Conclusions
We studied how the combination of terracing and mulching influences
water use by jujube trees and their response to droughts in three
different years on the semiarid Loess Plateau of China. We found that
both the extreme and moderate droughts clearly reduced soil water
storage and modified soil water use patterns, causing a sharp increase
in the use of water from deep layers. Furthermore, the extreme rather
than moderate drought resulted in a significant decrease in
transpiration at both seasonal and annual scales. In addition, the
jujube trees exhibited isohydric behavior during the drought periods;
this allowed them to cope with extreme drought. Moreover, the combined
treatments effectively enhanced soil water availability, deep-layer soil
water and canopy transpiration, indicating higher water use efficiency
than with traditional land management. These results demonstrate that
the combination of terracing and mulching can help jujube trees to
survive extreme droughts. These findings provide insights into the
effective management of hillslope plantations in drylands, particularly
in the context of global warming.