Sustainable Utilization of Agricultural Land in Chengdu Metropolitan Area Based on Emergy Analysis

[Objectives]This study aimed to analyze the sustainable use of agricultural land in the Chengdu metropolitan area from 2006 to 2016.[Methods]Using Odum's emergy theory,an index system was constructed to evaluate the sustainable use of agricultural land,including total emergy input-output ratio,industrial emergy input-output ratio,environmental load index and sustainable use index of agricultural land based on emergy,to reflect the sustainable use of agricultural land in the Chengdu metropolitan area.The data base was a unified standard that was converted from various types of energy stored and flowing in the agricultural land system of the Chengdu metropolitan area,that is,emergy.[Results]From 2006 to 2016,the total emergy input-output ratio of agricultural land in the metropolitan area fluctuated and decreased,lower than the national average.The industrial emergy input-output ratio was generally in a fluctuating downward trend.The environmental load index of agricultural land in the metropolitan area was lower than the national average.However,it has been on the rise since 2012.During the corresponding period,the sustainable use index of the region also showed a downward trend.[Conclusions]The utilization rate of emergy in this area was low.The dependence of industrial emergy input-output ratio on industrial subsidiary energy and the degree of agricultural mechanization are constantly improving.The environmental resources in this area still have room for accommodation and have not been fully utilized.The sustainable use of agricultural land has been declining.

Competitiveness and Complementarity of Cocoon Silk Trade between China and Southeast Asia

In the context of the Belt and Road Initiative,it is of great significance to study the trade ties between China and Southeast Asia with cocoon silk as a link.Trend analysis,trade competitiveness index and trade complementarity index were comprehensively used in this paper to study the competitiveness and complementarity of the cocoon silk trade between China and Southeast Asia.The results show that the export trade volume of cocoon silk of China and Southeast Asia is decreasing while fluctuating,but it is difficult for other regions to replace their export trade status in the world market.The development trend of the replacement of the silkworm cocoon trade by the raw silk trade is presented.The cocoon silk trade of China and Southeast Asia is characterized by dislocation competition.China's raw silk export trade is competitive and has become the leader of the raw silk export camp.This paper further analyzes the changes and complementarities of the cocoon silk trade competitiveness between China and Southeast Asia.