Role of terracing in water-balance components of Platycladus orientalis
during normal and dry years in the Loess Plateau, China
Abstract
Extensive ecological projects, including terracing engineering and
vegetation rehabilitation, have been implemented in many water-limited
mountains across the world, aiming to combat drought and control water
erosion. Nevertheless, due to the complexities of climate, terracing,
and vegetation types in actuality, knowledge gaps regarding the role of
terracing on water balance remain. Therefore, to better understand the
influence of terraces on water budget in a normal (2015) year and dry
(2016) year, a field experiment was conducted in a typical dry loess
hilly area of China. The effects of adverse grade tableland terraces,
fish-scale pits and the natural slope on water content change were
analyzed on the slope of Platycladus orientalis by the
water-balance technique and equations. The results showed that, compared
with natural slope, terraces had higher water budget benefits both in
dry year (+ 1.08~12.24 mm) and normal water year (+
15.71~27.29 mm), and adverse grade tableland terrace had
the best performance. Although precipitation was the primary factor
affecting water inputs, terraces can significantly increase soil water
content. Evapotranspiration and runoff were the main water loss terms,
but terrace also can help to reduce runoff water loss. Overall,
transformation of terraced fields can optimize the forest structure and
improve the eco-benefits at the slope scale.