Deng Jian, Zhao Fa Zhu, Han Xin Hui, Feng Yong Zhong, Yang Gai He
College of Agronomy, Northwest A&F University, Yangling 712100, Shaanxi, China.
Shaanxi Province Research Center of Recycle Agricultural Engineering and Technology, Yangling 712100, Shaanxi, China.
Ying Yong Sheng Tai Xue Bao. 2016 May;27(5):1576-1584. doi: 10.13287/j.1001-9332.201605.018.
To objectively evaluate and compare the stability and sustainability of different planting patterns of typical watersheds in Loess Plateau of China after the Grain for Green Project, this paper used the emergy analysis method to quantify the emergy inputs and outputs of three watersheds with different planting patterns, i.e., both grains and fruit trees (Gaoxigou watershed), mainly grains (Wuliwan watershed) and mainly fruit trees (Miaozuigou watershed). In addition, an emergy analysis system was established to evaluate the suitability of the three patterns from the perspectives of natural resources pressure as well as social and economic development levels. More than 75% of the total emergy inputs of all the three watersheds were purchased, and nonrenewable emergy inputs had a much larger contribution than renewable emergy inputs, indicating the characteristic of low emergy self-sufficient ratio and considerable high environmental loading ratio. The pattern of planting grains had high emergy inputs but low emergy outputs, while the patterns of planting fruit trees and planting both had high emergy inputs and outputs. The energy densities of all three patterns reached two times of the average of agricultural systems in China. Especially, the net emergy of planting grains pattern was the lowest while that of planting both grains and fruit trees was the highest. The environmental sustainability index (ESI) of planting grains pattern was less than 1 and both emergy and ESI were much lower than national averages. The ESI of planting both grains and fruit trees pattern was the highest. In summary, comparison of the three patterns showed that planting both grains and fruit trees had better sustainability and high stability and the emergy production efficiency was high. Thus, it was suggested to change the agricultural development from watershed based units to multi-industry integrated mode.
为客观评估和比较中国黄土高原典型流域实施退耕还林工程后不同种植模式的稳定性和可持续性，本文采用能值分析方法对三种不同种植模式的流域，即粮果兼作（高西沟流域）、以粮为主（五里湾流域）和以果为主（庙咀沟流域）的能值输入与输出进行量化。此外，建立了能值分析系统，从自然资源压力以及社会经济发展水平的角度评估这三种模式的适宜性。所有三个流域总投入能值的75%以上为购入能值，不可再生能值投入的贡献远大于可再生能值投入，表明能值自给率低、环境负载率相当高的特征。种粮模式能值投入高但产出低，而种果模式和粮果兼作模式能值投入和产出均较高。三种模式的能值密度均达到中国农业系统平均值的两倍。特别是，种粮模式的净能值最低，而粮果兼作模式的净能值最高。种粮模式的环境可持续性指数（ESI）小于1，能值和ESI均远低于全国平均水平。粮果兼作模式的ESI最高。综上所述，三种模式比较表明，粮果兼作具有更好的可持续性、高稳定性且能值生产效率高。因此，建议将农业发展从以流域为单元转变为多产业融合模式。
