渭-库绿洲多尺度景观格局与盐度关系

发布时间：2019-01-01 18:20

【摘要】：中国盐渍化土壤面积大,分布广,对区域农业发展构成了严重的威胁。探索土壤景观格局与盐度的关系将有助于盐渍化监测和评估。该研究选择渭-库绿洲GF-1影像为数据源,结合研究区同期38个样点不同剖面土壤盐度数据,对样点缓冲区景观格局与土壤盐度做Pearson相关分析和逐步回归分析,揭示土壤盐度空间分布格局,探讨景观格局与盐度的定量关系。结果表明:1)水平方向上,土壤盐分高值区主要集中分布在绿洲东部荒漠地带和绿洲西部农牧交错区;垂直方向上,渭-库绿洲表层土壤盐渍化现象最为严重,其他各层土壤盐渍化情况相对较轻,盐渍化程度随着深度下降呈降低趋势;2)绿洲区域易受人类活动影响,景观破碎化程度高,而同一区域不同梯度下,随着缓冲距离的增加,区域景观类型增多、均质性降低、多样性增强;3)耕地利用数量指标能较好指示土壤盐度状况,而水体面积、盐渍地面积、其他用地面积、最大斑块指数(largest patch index,LPI)、蔓延度(contagion index,CONTAG)和分维数(perimeter-area fractal dimension,PAFRAC)对盐度影响相对较弱;4)除0~10 cm层外,自10~20 cm至80~100 cm层逐步回归方程的自变量中,耕地面积、水体面积和最大斑块指数LPI为负效应,而盐渍地面积、其他用地面积、CONTAG和PAFRAC为正效应,最优回归方程决定系数为0.537。该研究确定了渭-库绿洲土壤盐度的分异规律,以及不同盐度对绿洲景观格局的影响程度。研究结果可为西北干旱区绿洲土壤盐度预警提供理论依据,同时为干旱区景观格局研究提供一定的参考价值。
[Abstract]:The salinized soil in China has a large area and wide distribution, which poses a serious threat to the development of regional agriculture. Exploring the relationship between soil landscape pattern and salinity will be helpful for salinization monitoring and assessment. In this study, GF-1 images of Wei-reservoir oasis were selected as data sources, and Pearson correlation analysis and stepwise regression analysis were made on landscape pattern of buffer zone and soil salinity in different sections of 38 sample sites in the same period in the study area. The spatial distribution pattern of soil salinity was revealed and the quantitative relationship between landscape pattern and salinity was discussed. The results showed that: 1) in the horizontal direction, the high value of soil salinity was mainly distributed in the desert zone in the eastern part of the oasis and in the ecotone of agriculture and animal husbandry in the western part of the oasis; In the vertical direction, the phenomenon of soil salinization in Wei-reservoir oasis is the most serious, the other layers of soil salinization is relatively light, and the salinization degree decreases with the decrease of depth. 2) Oasis region is easy to be affected by human activities, and the landscape fragmentation degree is high. However, with the increase of buffer distance, the regional landscape types increase, the homogeneity decreases and the diversity increases under different gradient of the same area; 3) the quantitative index of cultivated land use can better indicate the soil salinity, but the water area, saline land area, other land area, maximum patch index (largest patch index,LPI), contagion index,CONTAG and fractal dimension (perimeter-area fractal dimension,) PAFRAC) has a relatively weak effect on salinity. 4) except for 0 ~ 10 cm layer, among the independent variables of stepwise regression equation from 10 ~ 20 cm to 80 ~ 100 cm layer, the area of cultivated land, water body area and maximum patch index LPI were negative effects, while salinized land area, other land area, CONTAG and PAFRAC were positive effects. The determination coefficient of the optimal regression equation is 0.537. This study determined the law of soil salinity differentiation in Wei-reservoir oasis and the influence of different salinity on the landscape pattern of the oasis. The results can provide theoretical basis for early warning of soil salinity in arid oasis in northwest China, and also provide some reference value for the study of landscape pattern in arid region.
【作者单位】：新疆大学资源与环境科学学院;新疆大学绿洲生态教育部重点实验室;
【基金】：国家自然科学基金项目(U1303381;41261090;41130531) 高分辨率对地观测重大专项(民用部分)(95-Y40B02-9001-13/15)
【分类号】：S156.4;P901

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