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| DOI：10.13522/j.cnki.ggps.2020119 |
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| Effects of Topographic Factors on Soil Physical and Chemical Properties and Plant Species |
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SUN Liying, LI Qingya, PEI Liang, WU Hui , CHEN Lajiao
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1. Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China;2. University of Chinese Academy of Sciences, Beijing 100049, China; 3. Hangzhou Dianzi University, Smart City Research Center, Hangzhou 310012, China; 4. Zhejiang Regional Collaborative Innovation Center for Smart Cities,Hangzhou 310012, China; 5. Aerospace Information Research Institute, CAS, Beijing 100094, China
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| Abstract: |
| 【Objective】Soil properties and vegetation types are important factors affecting soil erosion, which are of great significance for controlling soil erosion and taking reasonable soil and water conservation measures. Both soil properties and vegetation are restricted by topographic factors. The important feature of the hilly area of red soil in Jiangxi Province is that the terrain is complex. The influence of topographic factors on soil physical and chemical properties and vegetation cover is an important basis for improving soil erosion prevention and land use structure adjusting, which is also of significance for improving soil and water conservation measures and ecological environment protection. However, the laws and mechanisms of the terrain factors’ influencing on soil properties and vegetation are not clear in hilly orchard of red soil region in southern Jiangxi Province. In this paper, the impacts of topographic factors, such as slope gradient, slope direction and slope position, on soil physical and chemical properties(total nitrogen (TN), total potassium (TK), total phosphorus (TP), total organic carbon (TOC) and soil moisture content) and the number of plant species were investigated, which can provide scientific reference for the fine development of hilly orchards and the comprehensive benefits improvement of soil and water conservation measures in hilly slope land of red soil region in southern China.【Method】Taking the soil and water conservation demonstration area of hilly orchard in the red soil region of southern China as the research area, soil sampling was carried out by five-point sampling method, vegetation survey was carried out by quadrat method, the topographic factors of each sampling point were determined by ArcGIS, and the differences of soil physical and chemical properties and plant species with topographic factors and their correlations were analyzed by using statistical software (SPSS 22.0).【Result】 The change trend of soil moisture content at different slope grades was 5o~10o>10o ~15o>15o~25o>0o~5o, and the lowest soil moisture content is 18.6% in 0o~5o area. With the change of both slope gradient and slope direction, soil total nitrogen (TN), total potassium (TK), total phosphorus (TP) and total organic carbon (TOC) showed no significant differences. There were no significant differences in TN, TK and soil moisture content at different slope positions. The contents of TP and TOC increased in lower slope positions. There were 183 species of plants in the study area, and the number of plant species showed significant differences with slope gradient, slope direction and slope position. The variation trend of the number of plant species with slope gradient was 0o~5o>10o~15o>15o~25o>5o~10o. With the change of slope direction, the number of plant species on the sunny slope was much higher than that on the shady slope. The change trend of the number of plant species was lower on the top slopes, with the order of middle slope> up slope > down slope along slope. 【Conclusion】All these results demonstrated that the topographic factors have certain influences on the soil properties and plant species in the hilly area of the red soil region in south China. The plant species in the study area showed significant differences with the slope gradient, slope direction and slope position. While, the slope gradient was the dominant topographic factor for the change of soil moisture content, and the slope position was the dominant topographic factor for the change of soil TP and TOC. Therefore, the influence of topographic factors should be taken into full consideration in the careful development of orchards and the spatial allocation of water conservation measures in hilly red soil region of southern China, for the higher economic income and the comprehensive benefits of soil and water conservation measures. |
| Key words: soil and water conservation; vegetation survey; soil sampling; slope gradient; slope direction; slope position |
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