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北京地区无霜期185天左右,年平均气温11—12℃,年平均降雨量584毫米,70%以上集中在夏季,形成春旱夏涝的气候特点。西部及北部山区以一季春玉米为主,浅山丘陵区水浇地实行小麦玉米套种;近郊及东南郊低洼易涝地,实行稻麦两熟或一季春稻。面积最大的平原产粮区,六十年代至七十年代初期主要是小麦玉米两茬套种,1973年以来平原水浇地几乎都是7.5尺畦三种三收。推行这一种植方式后,夏粮因播种面积和占地比例扩大而大幅度增
The frost-free period in Beijing is about 185 days with an average annual temperature of 11-12 ℃. The average annual rainfall is 584 mm. Over 70% of the rainfall is concentrated in the summer, forming a climatic feature of spring drought and summer flood. The western and northern mountainous areas are dominated by seasonal spring maize and wheat-corn intercropping in irrigated fields in the shallow hills and hilly areas. In the suburbs and the low-lying flood-prone lands in the southeast suburbs, rice and wheat two-cropping or one-season spring rice are practiced. The largest plain grain-producing area was mainly interplanted with wheat and wheat during the 1960s and early 1970s. Since 1973, almost all of the plain was irrigated to 7.5 ft in size and three in three. After the implementation of this planting method, the summer grain has been greatly increased due to the expansion of sown area and land occupation