1981年至1987年,对稻田不同多熟种植方式进行了定位观察。结果表明:(1)随技术的进步,本区水热状况较好的稻田种植双季稻亩产可过“双纲”,种植麦稻稻亩产可过“吨粮”;(2)稻田进行多熟种植,把土壤与作物间的物质循环提到较高的水平。只有增加投入,才能维持地力及提高产出;(3)随复种指数的提高,作物从土壤中取走的钾素剧增,秸秆还田及施有机肥归还土壤钾素效果明显。 From 1981 to 1987, different multi-cropping methods of paddy field were observed. The results showed as follows: (1) With the advancement of technology, double cropping of double cropping rice per mu in paddy field with better water and heat conditions in this area can be " Multi-cropping is carried out to raise the material cycle between soil and crop to a higher level. (3) With the improvement of multiple cropping index, the potassium taken from the soil by crops increased sharply, and the return of straw and organic manure to soil K was obvious.