农地集约利用的碳排放效率分析与低碳优化

提高农地利用集约水平与控制农地利用碳排放量容易陷入两难选择的困境,理想的碳排放效率可以寻找到以碳排放作为成本,适度的农地利用集约水平。该文构建农地集约利用度计算模型与农地集约利用投入产出指标,计算中国31个省份的农地集约利用度;基于松弛测度(slacks-based measure,SBM)模型,构建SBM模型投入产出指标,计算各省份的农地集约利用碳排放总效率、技术效率与规模效率。研究结果表明:农地集约利用程度高低与农地集约利用碳排放总效率高低并不保持普遍一致;农地集约利用碳排放总效率有效省份集中分布在西部地区,农地集约利用度较高的长三角、珠三角、京津冀地区主要省份的农地集约利用碳排放总效率普遍较低;区域农地集约利用碳排放技术效率不足是导致总效率偏低的主要原因,而规模效率不足对总效率影响较小。因此针对总效率无效省份,给出调整投入冗余量、期望产出不足量与非期望产出冗余量的低碳优化方案,并构建结合了东、中、西部地区区域农地利用与经济发展特点的低碳优化策略,以期最终可以改善农地集约利用碳排放效率。

Analysis of carbon emission efficiency and optimization of low carbon for agricultural land intensive use

Abstract: There is a dilemma between raising the intensive use level of agricultural land and controlling carbon emissions from agricultural land use. Carbon emissions from agricultural land use can be considered as a cost, and the suitable intensive use level of agricultural land should acquire a good efficiency of carbon emissions from agricultural land use. First, an assessment model for evaluating agricultural land use intensity was established in this article, and the input-output indices of agricultural land intensive use were selected. The input-output indices of agricultural land intensive use were composed of labor input per unit of agricultural land, capital input per unit of agricultural land, technique input per unit of agricultural land, value-added of agriculture per unit of agricultural land, grain products per unit of agricultural land, income from household business per unit of agricultural land, and ammonia-nitrogen emission from agriculture per unit of agricultural land. Secondly, the intensity values of agricultural land intensive use in 31 provinces were computed. Thirdly, based on a slacks-based measure model, the input-output indices were established. The input-output indices applied in the slacks-based measure model were composed of labor input per unit of agricultural land, capital input per unit of agricultural land, technique input per unit of agricultural land, value-added of agriculture per ton of carbon emission, grain products per ton of carbon emission, income from household business per ton of carbon emission, and ammonia-nitrogen emission from agriculture per ton of carbon emission. Fourthly, this article calculated the total efficiency values, technical efficiency values, and scale efficiency values of carbon emission from agricultural land intensive use in 31 provinces and designed an input-output optimization of agricultural land intensive use. Lastly, low-carbon optimization strategies for agricultural land use in provinces whose total efficiencies of carbon emission were inefficient were put forward. The results showed that: 1) Consistency between agricultural land use intensity and its efficiency of carbon emissions does not exist widely in China, and the provinces whose intensity values of agricultural land use are large are mainly located in eastern China and the traditional farming zone. 2) The provinces whose total efficiencies of carbon emission from agricultural land intensive use are DEA efficient were mainly distributed in western China, and the total efficiencies of provinces in the Yangtze Delta, the Zhujiang Delta and Jing-Jin-Ji Megalopolis which are in an economically developed area are widely low. 3) The main reason for the low total efficiency was the imperfect technical efficiency of carbon emissions from agricultural land intensive use, and the imperfect scale efficiency had little effect on the low total efficiency. 4) In order to improve the total efficiency of carbon emissions from agricultural land intensive use, some measures should be adopted according to the local features of agricultural land use and the economy. These measures mainly consist of transferring agricultural labor, controlling carbon sources input, developing low-carbon and high-output agriculture, etc. Effective measures can be applied to control the carbon emissions from agricultural land use, and also can be added to the good outputs which contain added value of agriculture, grain output, and income from increased household business. of course, the emissions of ammonia nitrogen discharged from agriculture can also be reduced by improving agricultural land use.