利用1989、2000及2006年3期TM遥感影像,采用遥感技术和地理信息系统相结合的方法,对陕北农牧交错带草地面积的时空演变进行分析.分析表明:从1989年到2000年,由于土地开发利用频繁,草地面积退化较快;从2000年到2006年,草地面积减少得比较缓慢.并利用Markov模型对陕北农牧交错带草地面积的变化情况进行模拟预测,预测表明:陕北农牧交错带草地面积将进一步减少,至2030年,草地面积将减少了21.36万hm2,草地的面积将继续减少.%In order to avoid low efficiency, high crushing rate and expensive operating costs in traditional drying process of maize ear, a kind of mechanical drying equipment was designed. It is simple in structure, easy in unloading and convenient in drying maize at different stages. The equipment was used for drying maize ear in different processes,and the results show that the two-stage drying processes can dry maize ear more efficiently. It can save 21 hours as compared to traditional drying process and the average drying rate was also improved by 42.8 ％, operating costs reduced by 36.8％, the maize crushing rate was decreased by 2.2％.
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