Gridded Assessment of Ecological Vulnerability in Loess Hilly Region of Western Henan Province, China

Based on meteorological, remote sensing, socio-economic data in 2000 and 2019 and PSR (Pressure-State-Response) evaluation model, an evaluation index system of ecological vulnerability in the loess hilly region of western Henan Province was constructed. Using spatial principal component analysis and spatial autocorrelation analysis, the ecological vulnerability of the study area was quantitatively evaluated with 2km×2km grid as the research scale, and the driving force of ecological vulnerability was determined by principal component load matrix analysis. The results show that: (1) The ecological environment in the Loess hilly region of western Henan showed a deteriorating trend from 2000 to 2019. (2) The vulnerability degree of the ecological environment in different counties was obviously different, and the vulnerability degree in the main city and suburbs was always at an extreme vulnerable level, while other regions showed different trends. (3) From 2000 to 2019, the ecological vulnerability had significant positive correlation and aggregation characteristics. The H-H clustering areas were mainly distributed in extreme vulnerable areas, while the L-L clustering areas are mainly related to negligible and light vulnerable areas. (4) The main driving factors of ecological vulnerability in the loess hilly region of western Henan are elevation, slope, terrain relief, degree of land use, annual mean precipitation, NDVI, annual mean temperature, land use type and urbanization rate.

Effects of water-saving pruning on the growth and water consumption of jujube (Ziziphus jujuba Mill.) in a loess hilly region with deep soil desiccation

In order to study whether jujube trees can grow normally under rain-fed conditions in loess hilly areas, we planted jujube trees (Ziziphus jujuba Mill.) 4 years after felling a 23-year-old apple orchard. The growth process of the jujube trees and the variation in soil water content (SWC) were monitored for three consecutive years following planting in order to study the effects of the water-saving pruning (WSP) technique. Results showed that: (1) The soil at a depth of 0–1,000 cm had been desiccated when the area was an apple orchard. (2) Under rain-fed condition, the jujube trees with WSP technique were always able to maintain normal growth while the jujube trees with conventional pruning method had a normal growth stage of only 4 years. And the water use efficiency of the jujube trees with WSP technique was much higher than that of the jujube trees with conventional pruning. We recommend WSP in jujube orchard management, because the jujube trees with WSP could maintain normal growth in deep dried soils of the loess hilly region, as WSP can reduce the water consumption of the jujube trees and may has positive effect on soil moisture restoration.