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[摘要]：Some analysts point to continuing advances in agricultural technology and declining global population growth rates to Predict a substantial surplus of agricultural land by 2050. Such surplus land could be diverted into growing biomass for renewable energy to help overcome the global challenge of climate change. Others Suggest that diversion of agricultural land into bioenergy will exacerbate risk of chronic food shortage by 2050. On balance it appears that declining population growth rate, continuing technology advance, and intensifying use of existing global agricultural land could Support sufficient food production as well as some bioenergy production. Competitive bioenergy requires development of second-generation (lignocellulosic) feedstocks rather than first-generation (starch, sugar, and oilseed) feedstocks. Second-generation feedstocks from woody crops have the potential to complement intensive agriculture and ameliorate its environmental impacts. Woody biomass crops may therefore have a lower effective cost than generally perceived. The potential for woody crops is indicated with an economic analysis of mallee, a woody crop being developed for low-cost biomass production in Western Australia. Mallees are short, multistemmed eucalypts grown in dispersed narrow belts, harvested on a regular short cycle, and regenerated by coppice. When integrated into the dryland agriculture of this region it has file potential to improve the economic and environmental performance of the entire system. |
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