西北干旱区不宜作为我国耕地后备资源基地

Arid Northwest China Can Not Be Regarded as the Farmland Reserve Base

我国人口众多、粮食安全意义重大,但我国西北干旱区不能承受"耕地后备资源基地"之重任。西北干旱区面临严峻的环境问题,包括高山冰川资源减少、河流萎缩、荒漠化、盐渍化、沙尘(暴)等,对我国生态安全与区域可持续发展影响深远。西北干旱区所谓的"耕地后备资源",其实就是沙漠与绿洲之间具有较好植被覆盖的过渡带,也是宝贵的绿洲缓冲带,对于绿洲稳定性具有重要的保护作用;它们一旦被开垦,恢复起来非常困难甚至难以恢复,开垦的生态成本过大。在我国大规模实施退耕还林、生态安全建设、可持续发展战略的大背景下,耕地后备资源的概念,特别是干旱区作为主要耕地后备资源基地的概念,需要做出适当调整和淡化。从全国生态安全格局来看,西北干旱区防治荒漠化威胁具有全局性战略意义,应该突出区域生态服务功能,走节水与高产之路,使有限的水资源发挥最大的作用。为此,建议中央政府考虑在西北干旱区颁布"禁垦令",严格限制耕地扩张并适度减少耕地面积。我国粮食增产、稳产的重任只能放在东部粮食主产区,靠科技进步、提高单产来实现。

In spite of large population and severe food security issues in China, arid northwest China can not be regarded as the main ＂farmland reserve base＂. The reason is that arid northwest China faces the severe environmental problems including the reduction of alpine glaciers, shrinkage of rivers, dying-off of desert vegetation, desertification, salinization, sandstorm, etc. , and these problems result in the serious impact on ecological security and sustainable development of China. These problems can almost be found in Minqin County of Gansu Province, which can be called the ＂Minqin aporia＂, characterized by the serious drawdown of groundwater level, ever-deteriorating desertification, and even the appearance of ecological refugees. The so-called ＂farmland reserve resources＂ are actually the well-vegetated eeotones between oases and sandy deserts, which protect ecologically the oases against wind-blown sand disasters. Formed in a long history, they are very difficult or costly to restore once reclaimed. Viewing from national ecological security pattern, desertification prevention in arid northwest China is of country-wide significance. As a result, its ecological service function should be enhanced by developing area-specific agriculture and water-saving irrigation based on scientific research and high-technology. All of these can aim to make rational utilization of limited water resources in arid land. It is suggested that the central government issue the ＂Reclamation ban＂ to prevent farmland expansion and even to reduce farmland area in arid land. It could be responsible to increase and stabilize grain production of China in the main food production regions in east China.