Water uptake strategies by typical broadleaf and coniferous trees in the Loess Plateau mountain area of northern China

Poor precipitation in the Loess Plateau area may significantly influence
water uptake strategies of the plants growing there. The water sources of
these trees have not been studied to date. We investigated the impacts of
precipitation (before and after) on water uptake strategies of typical
broadleaf and coniferous trees in the Loess Plateau mountain area of
northern China by using hydrogen and oxygen stable isotope techniques. Our
results indicated that water sources of these two tree types varied before
and after rainfall. Robinia pseudoacacia, a broadleaf tree, absorbed water
majorly from the 30–40 cm (57.8%) soil layer before precipitation and from
the 20–30 cm (58.5%) soil layer after precipitation. However, Pinus
tabuliformis, a coniferous tree, mainly absorbed water from 20–30 cm
(24.9%) and 10–20 cm (21.6%) soil layers before precipitation and from
0–10 cm (39.8%) and 10–20 cm (44%) soil layers after precipitation.
Moreover, the herbaceous of broadleaf plant has higher complexity of the
community through filed investigation. Thus, R. pseudoacacia and P.
tabuliformis exhibited peculiar difference in terms of water uptake,
indicating that they are suitable to grow together as forest vegetation in
arid and semi-arid areas. Overall, our results provided vital information
for sustainable afforestation management in the Loess Plateau mountain
area of northern China.