Effects of Long-Term Application of Controlled Release Nitrogen Fertilizer on Crop Yield and Soil Nitrogen Supply Characteristics of Wheat-Maize Rotation System in Fluvo-Aquic Soil Area
The long-term positioning test of controlled release nitrogen fertilizer for 10 consecutive years in Dezhou,Shandong Province was used as a platform for this experiment.Five treatments were set as no nitro-gen fertilizer(PK),urea at farmers conventional application rate(FP),urea at optimized application rate(OPT),controlled release nitrogen fertilizer(CRF1)and controlled release nitrogen fertilizer with reduction by 20%(CRF2).Soil samples were collected at the tasseling stage and filling stage of maize,and the jointing stage,booting stage,filling stage and maturity stage of wheat.The soil pH,contents of total nutrients,ammo-nium nitrogen,nitrate nitrogen and alkali-hydrolyzable nitrogen and crop yield were determined in order to ex-plore the effects of long-term application of controlled-release nitrogen on crop yield in wheat-maize rotation system and the supplying characteristics of soil nitrogen in fluvo-aquic soil area.The results showed that long-term application of controlled-release nitrogen fertilizer could significantly improve soil nitrogen supply capaci-ty.Compared with OPT treatment,CRF1 treatment increased the alkali-hydrolyzable nitrogen by 14.10%and 9.45%at maize tasseling stage and filling stage respectively,increased the ammonium nitrogen by 125.53%at tasseling stage,and increased the ammonium nitrogen and nitrate nitrogen by 62.48%and 200.29%respec-tively at wheat jointing stage.Compared with FP treatment,the maize,wheat and annual yields of CRF1 treat-ment increased by 13.13%,16.73%and 14.89%respectively,while the annual yield of CRF2 treatment did not change significantly.Through the random forest model analysis,it was found that the maize yield was closely related to the soil alkali-hydrolyzable nitrogen at filling stage and the total nitrogen at mature stage un-der different fertilization modes,and the wheat yield was comprehensively regulated by nitrate nitrogen at joint-ing stage,alkali-hydrolyzable nitrogen and ammonium nitrogen at booting stage,alkali-hydrolyzable nitrogen at filling stage,and soil total nitrogen and alkali-hydrolyzable nitrogen at mature stage.In summary,controlled release nitrogen fertilizer could increase soil total nitrogen,alkali-hydrolyzable nitrogen,nitrate nitrogen and ammonium nitrogen contents at key growth stages of maize and wheat by regulating nitrogen release,thereby significantly increased the crop yield,and controled no reduction of crop yield under 20%reduction of con-trolled release nitrogen fertilizer.
万方数据
维普
