退耕还林工程实施前后黄土高原地区粮食生产时空变化

China＇s University Development from the Perspective of System Science

始于1999的退耕还林工程是中国政府针对西部生态脆弱区所实施的重大生态工程。工程的实施对当地粮食生产的影响及由此而产生的政策效果是值得研究的问题。该研究利用1996年、2003年和2007年黄土高原地区分县统计数据,对中国黄土高原生态脆弱区1999年以来所实施的退耕还林工程对粮食生产能力的影响进行了分析。结果显示,从1996年到2003年,研究区粮食播种面积下降剧烈,之后有所回升,到2007年大部分县粮食播种面积下降的势头得以遏制;从1996年到2007年,研究区粮食总产量下降,粮食单产水平提高;研究区粮食单产水平远低于全国平均水平,人均粮食产量略低于全国平均水平,二者都表现出较大的年际波动性。粮食生产水平越低,其年际波动性越大。不稳定的粮食产量会强化农民的垦殖动力,不利于退耕工程实施成果的巩固。应根据各地的条件,有区别有节奏按适度规模循序渐进地推进退耕还林工程的实施,并在政策上对农民的生计进行引导和保障,以巩固退耕工程实施效果。

From the perspective of system science, the university belongs to the complex and dynamic system with its inner principles. It shares many characteristics, such as multi- ple time scale, significant retardance, high nonlinearity, multiple feedback, broad openness. With the domination and restriction of the principles, it＇s a long historical process to con- struct the world-class universities in the developing countries. Such problems as uneven de- velopment, deteriorative quality and moral deficiency, result from inconsistency with the principles. Facing the outstanding issues, the government and the policymaker of the univer- sity should consider, plan and organize the comprehensive reform promoted by external and internal force, to advance the scientific development in universities.