不同耕作模式对农田系统能值的影响

Effects of Different Tillage Modes on Farmland System Emergy

基于能值理论分析体系,比较不同耕作模式下农田系统的生态指标和可持续发展性,为筛选出适合本地区应用的农田耕作模式提供理论依据。本试验共设置农民传统耕作(CK)、传统耕作+秸秆还田(T1)、深松耕作+秸秆还田(T2)、免耕+秸秆还田(T3)4个处理。农田能值系统分析可知,CK模式下农田生态系统经济发展活力低,属于消费型生态经济系统,环境负载率超过T1模式的4倍,说明秸秆还田能有效降低农田生态系统的环境负载率,降低农田对不可更新环境资源依赖程度,减轻农田环境压力;同时秸秆还田能提高土地面积的能值投入量,T1、T2、T3处理能值投入率分别为农民传统耕作的1.57、1.63、1.59倍,增强农田生态系统集约化程度;四种不同处理(CK、T1、T2和T3)下农田生态系统可持续发展指数分别为0.31、0.91、1.01、1.02,说明T1、T2、T3处理均能显著提高农田系统可持续发展水平,其中T2、T3为更适合本地区的农业生态耕作模式。

Based on the emergy theory analysis system,the ecological indexes and sustainable development of farmland system under different tillage modes were com;pared to provide theoretical bases for selecting suitable tillage mode for local application. In this study,four treatments were set as traditional tillage( CK),traditional tillage + straw returning( T1),deep loosening + straw returning( T2),and no-tillage + straw returning( T3). The results showed that the farmland ecosystem had low economic development vitality under CK mode,which belonged to consumption type of ecological economic system with the emergy loading rate as4 times more than that of T1 mode. It indicated that straw returning could effectively reduce the loading rate of farmland ecological system,reduce the dependence of farmland on unrenewable resources,and reduce the pressure of farmland environment. At the same time,straw returning could increase the input of emergy of land area. The emergy input rates of T1,T2 and T3 treatment was 1. 57,1. 63 and 1. 59 times of that of CK,respectively,and the intensification of farmland ecosystem could be enhanced. The sustainable development index of farmland ecosystem under the four different treatments was 0. 31,0. 91,1. 01 and 1. 02 respectively,which indicated that T1,T2 and T3 treatments could significantly improve the sustainable development level of farmland system. Among which,T2 and T3 tillage modes were more suitable for the local agricultural ecology.