2.3. Experimental design
In order to enhance the ability of jujube trees to resist extreme
seasonal droughts, a mulching experiment was conducted at this site in
2013. First, branches pruned from jujube trees during normal management
and maize stems were trimmed to lengths of approximately 20 cm and then
used as mulch on the surface of half-moon terraces, applied at a
thickness of 15 cm, resulting in two combinations of terracing and
mulching (Figure S1), hereafter JBT and MST, respectively. The mulch
material can be washed off the terraces by rapid overland flow during
heavy rainstorms or blown away by strong winds. Therefore, new branches
or maize stems were added to terraces every spring to maintain a
constant thickness. Two other treatments, just half-moon terracing (SHT)
and the traditional hillslope (control) land management practices, were
also examined. Each treatment included four replicates, and each
replicate comprised a 24-m2 plot (4 m × 6 m),
including three jujube trees. Therefore, there was a total of 16 plots
in the experiment.