基于能值分析的马尾松低效林林下种草养鸡耦合模式评价

Emergy analysis of chicken breeding modes under low-efficient Pinus massoniana forests

  • 摘要: 马尾松低效林是红壤侵蚀区典型植被类型。林下种草养鸡则是林下种草与林下养鸡的耦合新模式,既能解决马尾松林下水土流失问题,又能提高经济效益,实现生态种养循环,驱动水土流失治理。为科学评价马尾松低效林林下种草养鸡模式的生态经济效益,本文应用能值分析法,测评福建省长汀县三洲镇垌坝村传统林下养鸡(对照)、林下种草养鸡两种模式的能值自给率、能值投资率、净能值产出率、环境负载率、可持续发展指数和能值反馈率。结果表明,传统林下养鸡模式的能值自给率、能值投资率、净能值产出率、环境负载率、可持续发展指数和能值反馈率分别为0.860、0.166、2.125、3.380、0.629和0.026,林下种草养鸡模式上述指标值分别为0.400、1.510、0.870、1.370、0.635和0.290。林下种草养鸡模式的能值投资率、可持续发展指数比对照提高1.344和0.006个单位,显示更强的经济活力;能值自给率、环境负载率比对照下降0.460、2.010个单位,显示更低的环境负载。林下种草养鸡模式的净能值产出率低于对照1.255个单位,而能值反馈率高出对照0.264个单位。总体而言,林下种草养鸡耦合模式经济活力更强,环境负载更低,符合脆弱区林下经济发展趋势。侵蚀区土壤结构性差,限制了从系统外导入的化肥在循环系统中功能的发挥,导致系统净能值产出率、能值反馈率较低,这为该模式的优化指明了方向。

     

    Abstract: Pinus massoniana forest is a typical low-efficient vegetation type in eroded red-soil areas. Ecological breeding of chicken under forest is a new mode that includes traditional raising chicken under forest and grass planting underneath. This model can reduce soil erosion in P. massoniana forests and improve economic performance. To evaluate ecological and economic benefits of ecological breeding of chicken under P. massoniana forest, this paper used emergy analysis method to evaluate self-sufficiency, investment value, net emergy output, environmental load rate, sustainable development index and emergy feedback rate of traditional chicken breeding mode (CK) and ecological chicken breeding mode (ECB) under P. massoniana forests in Tongba Village, Sanzhou Town and Changting County. The results showed that self-sufficiency, investment value, net emergy output, environmental load rate, sustainable development index, and emergy feedback rate of CK were respectively 0.860, 0.166, 2.125, 3.380, 0.629 and 0.026. Then those of ECB were respectively 0.400, 1.510, 0.870, 1.370, 0.635 and 0.290. The values of investment and sustainable development indexes of ECB increased respectively by 1.344 and 0.006 over those of CK, showing stronger economic vitality. The self-sufficiency and environmental load rate of ECB reduced respectively by 0.460 and 2.010 compared with CK, showing lower environment stress. Net emergy output was lower by 1.255 units and emergy feedback rate higher by 0.264 units over CK. Input-output ratio of CK was 0.30, and that of ECB was 0.53, resulting in high emergy self-sufficiency. Net energy output rate and environmental load of ECB were lower than those under CK, while emergy investment rate and sustainable development index were higher. In general, ecological chicken breeding under forest had stronger economic vitality and lower environment stress, and consequently, was consistent with the trend of economic development in vulnerable forest areas. Poor soil structure in soil erosion areas limited the functions of chemical fertilizer in the circulatory system. This led to low net emergy output and emergy feedback rate. This result was indicative for the optimization of forestry economy modes.

     

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