The soil of the savanna ecosystem of Yuanjiang China is seriously degraded, especially owing to livestock grazing. The establishment of enclosures is widely regarded as an efficient, effective, and inexpensive practice for the restoration of degraded soils. However, the effect of enclosures on ecohydrological ecosystem services (e.g. water infiltration and distribution, water flow patterns, and water supply regulation) in the savanna system was unknown.
In a study published in Land Degradation & Development, researchers from Xishuangbanna Tropical Botanical Garden (XTBG) tried to assess the effect of grazing exclusion on water storage, soil infiltrability, and preferential water flows and explore related influencing factors in dry-hot savanna systems.
The researchers conducted experiments in the continuous grazing regions and enclosure regions in a savanna system in Yuanjiang, southwest China. They measured the root biomass of herb and woody plants, soil physical properties, water infiltration, and preferential water flow in each study site.
Compared to the grazing region, the soil hydrologic properties were significantly improved in the enclosures due to an increase in soil infiltrability and preferential flow paths. The enclosure region was also characterized by improved soil physical properties, such as lower bulk density, higher porosity and field water capacity.
The root and faunal activities were also increased in the enclosure region, which enhanced and promoted hydraulic redistribution in the three-dimensional soil profiles.
Moreover, the enclosure-induced restoration of herb and woody species could lead to the redistribution of water resources and the diversification of water supply, thereby promoting the water availability for different plant species.
"Our results confirm that enclosures can increase water infiltration and redistribution, accelerate recharge, and attenuate soil erosion, thereby contributing to soil water conservation and management in the savanna. Therefore, the grazing enclosures could be expanded periodically and cautiously to prevent soil degradation in the present savanna systems," said LIU Wenjie of XTBG.
LIU Wenjie Ph.D Principal Investigator
Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, China