上海郊区是单季晚粳稻产区,近几年来双季连作稻和一年三熟也在逐年扩大,晚茬麦面积很大,约占三麦(小麦、元麦、大麦)播种面积的60%以上。由于晚稻成熟迟,对后作播种三麦形成尖锐的茬口矛盾,抢收抢种农活集中,劳力畜力十分紧张,当时如遇阴雨,给三麦播种带来更大困难。晚茬麦由于失却播种适期,一般亩产只150—200斤,比适期播种 Shanghai suburbs is a single season late japonica rice producing area. In recent years, the double cropping continuous cropping rice and the third cropping year are also expanding year by year. The late cropping wheat area is very large, accounting for about 60% of the sown area of ​​three wheat (wheat, wheat and barley) %the above. Due to the late maturity of late rice, sowing three wheat after the formation of sharp stubble contradictions, grab the rush to concentrate farming, labor force is very tense, then in case of overcast, to San Mai sowing more difficult. Late crop due to loss of sowing period, generally only 150-200 kg per mu, sow more than the right