迄今,关于黄淮海地区石灰性稻田土壤上氮肥去向的研究极少。仅见的一个田间微区试验是有关氮肥表施作基肥的,而在生产中却多采用混施的方法。此外,盆栽试验表明,无水层混施能减少氮素损失。因此,有必要在本区稻田土壤上,采用田间微区的方法,进一步明确氮肥混施作基肥时氮素的去向,以及无水层混施在降低氮素损失、提高氮肥增产效果 So far, little has been done on the fate of nitrogenous fertilizers on calcareous paddy soils in the Huang-Huai-Hai region. Only one of the field trials observed in the field was nitrogenous fertilizer applied as a basal fertilizer, but in production, more methods were used. In addition, pot experiments showed that water-free layer mixing can reduce nitrogen loss. Therefore, it is necessary to use the method of field micro-area in paddy soils in this area to further clarify the direction of nitrogen in the application of nitrogenous fertilizer as basal fertilizer and the combination of non-aqueous layer to reduce nitrogen loss and increase yield of nitrogen fertilizer