Effects of Controlled Release Nitrogen Fertilizer on Yield and Soil Nutrient Regime of Wheat-Corn Rotation System
Based on a four years long-term fertilizer experiment of wheat-corn rotation system in Hengshui city,Hebei province,the effects of reducing N application by using controlled released urea (CRU) and different fertilization practices on wheat-corn yield and soil nutrient status were studied.The results showed that there was no significant difference on the crop yield between the treatments of basal application once and basal application plus one dressing application of the fertilizers.The treatment of CRU application reduced 30% N (CRU70%) increased the wheat-corn yield significantly in two seasons while the wheat/corn yields did not change significantly in the other seasons.Appling nitrogen fertilizer significantly increased the nitrate nitrogen (NO3--N) content in 0-40 cm soil layers compared to the no N treatment (CK).Basal application of 60 % nitrogen fertilizer and additional dressing application of 40 % nitrogen fertilizer significantly increased the content of NO3--N in 20-40 cm soil layer.The content of NO;-N showed no significant difference between the treatments of CRU70% and common urea nitrogen applied constantly (Urea100%).Treatment of CRU70 % restrained the NO3--N leaching effectively and the content of soil NO3--N in deep soil reduced 44.15%~89.21% compared with the treatment of Urea100%.The treatment of Urea100% significantly reduced top soil pH compared with other treatments.Nitrogen fertilizer application showed no significant effect on the contents of soil total nitrogen,organic matter,total phosphorus,available phosphorus.Compared with treatment of Urea100%,treatment of Urea60%+40% retarded the course of soil acidification and reduced the content of available potassium in surface soil.So there was no significant difference on crop yield and soil nutrient regime of wheat-corn rotation system between the treatments of CRU70% and Urea100 %.