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各类作物产量的丰欠与气候等自然条件的变化密切相关。人为因素如政策、品种,肥力、生产技术等条件,在目前还只能起到使粮食丰产幅度增大,或减产幅度缩小。各类作物丰欠的总体趋势依然受自然条件的制约,面一定地区的自然条件的变化又具有它特定的规律。为此,各类作物来年的产量丰欠趋势,可依据自然条件造成的历年粮食产量变化的周期规律进行预测。
The abundance of various crop yields is closely related to changes in natural conditions such as climate. At present, man-made factors such as policies, varieties, fertility and production technology can only increase the breadth of grain yield or reduce the reduction in output. The overall trend of various types of crop abundance is still constrained by natural conditions, and the change of natural conditions in certain areas has its own specific law. For this reason, the yield trend of various crops in the coming year is underdeveloped and can be predicted on the basis of the periodic pattern of changes in grain yield over the years caused by natural conditions.