基于地块尺度的耕地集约利用与环境压力关系—— 以塔里木河流域780 个地块为例

Relationship between intensive utilization and environmental pressure of cultivatedland: a case study on 780 cropland parcels in Tarim River Basin

  • 摘要: 为了揭示耕地高效利用与此过程中所产生的环境压力的关系, 基于农户抽样问卷调查, 利用集约度与环境负荷率指标, 分析了塔里木河流域780 个耕地地块集约利用与环境压力的关系。结果表明: (1)75.90%的地块集约度小于1 元·m?2, 环境负荷率随集约度的增长而明显增加; 18.60%的地块集约度在1~1.5 元·m?2 之间, 环境负荷率的增长小于集约度的增长, 在小幅波动的基础上保持较为平稳的趋势; 5.50%的地块集约度大于1.5元·m?2, 环境负荷率随集约度的增高反而呈降低趋势。(2)耕地投入结构的差异导致耕地环境压力的不同变化趋势, 不可更新工业能的投入比重增加会导致环境负荷率增大, 但是在增加不可更新工业能的同时加大可更新人工辅助能的投入可以抑制环境负荷率的升高。(3)作物种植类型与地块规模也在一定程度影响到耕地环境负荷的变化, 小麦与林果任何规模的地块环境负荷率都随集约度增长而增大; 小规模植棉地块, 环境负荷率随着集约度的增大而增强, 0.33 hm2 以上的大地块棉田, 环境负荷率随着集约度的增长特征没有小地块明显; 小地块瓜地集约度基本保持一致, 环境负荷率变化也较少, 而大规模瓜地环境负荷率随着集约度增加有所增大。

     

    Abstract: Intensive degree (ID) is a common index used to judge the effectiveness of land utilization. With increasing ID, cultivatedlands generate certain environmental pressures from extensive use of agro-chemicals like fertilizers and pesticides, and mulching,etc. This paper analyzed the intensity of utilization and environmental pressure of 780 cropland parcels in the Tarim River Basin(TRB) using data acquired from household questionnaire survey. The aim of the study was to explore environmental pressures generatedby highly intensive utilization of cultivated lands. The results showed that intensive utilization of cultivated lands caused somedegrees of environmental pressure in TRB study area. Environmental load ratio (ELR) of investigated cultivated lands revealedchanging trends with increasing IDs of cropland parcels. In 75.90% of the cropland parcels with ID < 1.0 Yuan·m?2, ELR increasedwith increasing ID. ELR change in 18.60% of cropland parcels with ID in the range of 1~1.5 Yuan·m?2 showed a stable trend relativeto increasing ID. Only in 5.50% of cropland parcels with ID > 1.5 Yuan·m?2 did LER decrease with increasing ID. Differences ininput structures in cultivated lands were the main driver of the variations in ELR. Rise in the proportion of non-renewable emergyinput resulted in increasing ELR. However, with the increasing non-renewable emergy input, ELR rise was restrained by enhancedrenewable emergy input. To a certain degree, differences in the trends of cropland parcel ELR suggested that in the study area, theutilization of most cropland parcels was primarily intensive. However, some cropland parcels had been transformed into advanceduse intensity. Environmental pressure of cultivated lands was related to crop type and cropland parcel size. For cropland parcels under wheat and fruits, ELR at any scale parcel increased with increasing ID. For cotton fields, small-scale parcel ELR increased with increasing ID. It, however, showed no obvious ELR change for large-scale cotton fields (>0.33 hm2). For cucurbits fields, LER wasstable due to low and stable ID driven by the predominantly small-scale cropland parcels. However, LER increased with increasingID once parcel size exceeded 0.33 hm2. It suggested that alleviation measures of environmental pressure of cultivated lands should beon the basis for crop type and cropland area.

     

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