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1982年4月,笔者作为农牧渔业部派出的访问学者赴美国密执安州立大学农学院学习工作一年.土壤测定及施肥建议情况作为考察内容之一,现将所获资料概略介绍,供国内工作的参考.密执安州位于美国的中北部地区,靠美国玉米带的东北端,北纬42一47°.由两个大半岛组成,被五大湖环绕,有11000个小湖遍布全州,还有长约36,000英里的大小河流.这就使本来位于北美大部中部的密执安州却有半海洋性气候特点.本州平均年降水量约800毫米,月分布较均匀,生育季节需水高峰期(7、8月份)又感缺雨.年平均气温7.6℃.有效积温1351℃(从10℃计起).州的中部宜农宜果,北部则主要为森林.该州农作物主要是玉米、大豆、小麦、干豆和苜蓿.近20年来密执安州农作物单产大幅度提高,除品种和栽培技术改进之外,施肥量的增加和施肥技术改
In April 1982, as a visiting scholar sent by the Ministry of Agriculture, Animal Husbandry and Fisheries, I went to study at Michigan State University College of Agriculture for one year and soil testing and fertilization proposals as one of the contents of the survey, the information obtained is now briefly introduced for Reference to the domestic work. Michigan is located in the central and northern regions of the United States, by the northeast end of the United States corn belt, latitude 42-47 ° .It consists of two large peninsulas, surrounded by the Great Lakes, 11000 small lake throughout the state, There are also about 36,000 miles of rivers, which makes the Michigan state, which was originally located in most of North America, has a semi-maritime climate with an average annual rainfall of about 800 millimeters, a more evenly distributed month, water for the growing season The peak season (July, August) is also a lack of rain. The annual average temperature of 7.6 ℃. Effective accumulated temperature of 1351 ℃ (from 10 ℃ count.) The central state of Yichang appropriate fruit, the north is mainly the main state of the crop is Corn, soybeans, wheat, dried beans and alfalfa Crop production in the Michigan state has increased significantly over the past 20 years, with the exception of improved varieties and cultivation techniques, increased fertilizer application and fertilization techniques