An Analysis of Soil Quality Changes in the Process of Ecological Restoration in Karst Rocky Desertification Area:A Case Study in Karst Ecological Restoration and Rehabilitation Region of Guzhou Village
Serious soil erosion and drastic decrease in soil productivity caused by karst rocky desertification can endanger the functions of karst ecosystem. Thus, to better understand the changes of soil quality in the process of ecological restoration, which can provide scientific basis for soil nutrient regulation, is important for ecosystem management in vulnerable karst rocky desertification area. This study was conducted in the karst ecological restoration and rehabilitation region of Guzhou village, 21 typical sample plots of Zenia insignis along a rocky desertification gradient were selected based on field survey and literature search, among which 9 sample plots are on a slope and 12 sample plots are in a depression area. Soil samples were collected along a rocky desertification gradient(potential rocky desertification, slight rocky desertification, moderate rocky desertification, and severe rocky desertification), and the changes of soil quality in different layer, indicating by soil bulk density, soil water content, pH value, soil organic matter, soil total nitrogen, soil total phosphorus , soil total potassium , available nitrogen, available phosphorus, and available potassium, were studied using laboratory analysis method. Results showed that, (1) Vegetation recovery in rocky desertification area provided more organic matter to the soil and therefore resulted in the increase of soil nutrient contents. (2) During the process of ecological restoration, soil quality was getting better and vegetation was accordingly growing better, which indicated that the effect of rocky desertification control effect was obvious. This also indicated that there was a positive relationship between the improvement of soil quality and the restoration of karst ecosystem in rocky desertification area. (3) From severe rocky desertification to slight rocky desertification, the average of total nitrogen in the slope area increased from 1.22 g·kg-1 to 1.88 g·kg-1, by 54.10%;the average of total nitrogen in the depression area increased from 1.13 g·kg-1 to 1.36 g·kg-1, only for 20.35%. The average of available nitrogen in the slope area increased from 84.55 mg·kg-1 to 164.31 mg·kg-1, by 94.33%;the average of available nitrogen in the depression area increased from 41.90 mg·kg-1 to 82.57 mg·kg-1, by 97.06%. The average of available potassium in the slope area increased from 36.61 mg·kg-1 to 58.52 mg·kg-1, by 59.85%;the average of available potassium in the depression area increased from 15.02 mg·kg-1 to 28.09 mg·kg-1, by 87.02%. (4) There is a synchronous relationship between the changes of soil quality and the process of eco-restoration in karst rocky desertification area. With the improvement of the rocky desertification, soil water content, soil organic matter, soil organic carbon, total nitrogen, available nitrogen, and available potassium showed an increasing trend, while soil bulk density and pH value showed a decreasing trend, which indicated an increase in soil fertility.
karstthe process of eco-restoration in karst rocky desertification areasoil qualityplantation forest of zenia insignis
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