检索规则说明:AND代表“并且”;OR代表“或者”;NOT代表“不包含”;(注意必须大写,运算符两边需空一格)
检 索 范 例 :范例一: (K=图书馆学 OR K=情报学) AND A=范并思 范例二:J=计算机应用与软件 AND (U=C++ OR U=Basic) NOT M=Visual
机构地区:[1]水利部中国农业科学院农田灌溉研究所
出 处:《灌溉排水》1999年第1期52-56,共5页Irrigation and Drainage
摘 要:以1997年的美国灌溉统计资料为基础,结合近20多年的数据,本文详细分析了美国的农田灌溉在近20多年的发展状况,并从地理位置、气候类型和灌溉规模等不同角度全面分析了美国各种灌溉方法的构成、灌溉所用动力类型和灌溉农田上的作物结构。结果显示,近20多年来,美国总灌溉面积中喷灌所占比例在不断增加,而地面灌溉比例则不断降低。1997的资料显示,在目前美国的灌溉面积中,喷灌是以中心支轴式系统为主,微灌以地表滴灌为主,而地面灌中则有3种类型的系统使用的较多。在灌溉农田的作物结构上,干旱地区的饲草类作物种植比例明显高于其它地区,而湿润地区的粮食作物、瓜果蔬类作物和棉花的比例较高。Based on 1997 Annual Irrigation Survey and Annual irrigation survey data in last 20 years, the development of irrigation in USA in last 20 years are analyzed in this paper. The constitution of various irrigation methods, the types of irrigation power units, the situation of irrigation wells and the crop constitution in irrigated land are also analyzed systematically on view points of geographical locations, climate features and total irrigation area. The results show that percentage of sprinkler irrigation has been increasing and the percentage of the surface irrigation has been decreasing gradually in last 20 years in USA. The analysis on 1997 annual irrigation survey points out that center pivot is the main system in sprinkler irrigation, surface drip/trickle is the main system in low flow irrigation, and three kinds of main system in surface irrigation are applied nearly equally. On the crop constitution in irrigated land, the proportions of the alfalfa and pasture hay crops are higher in arid and semi arid area, but the proportions of the grain crops, cotton and melons/fruits/vegetable crops are higher in humid area.
分 类 号:S274.1[农业科学—农业水土工程]
正在载入数据...
正在载入数据...
正在载入数据...
正在载入数据...
正在载入数据...
正在载入数据...
正在载入数据...
正在链接到云南高校图书馆文献保障联盟下载...
云南高校图书馆联盟文献共享服务平台 版权所有©
您的IP:216.73.216.117