减量施肥对水稻生长及氮素利用率的影响

通过在不同肥力水平土壤上设置不同幅度的氮肥减量试验,研究其对水稻产量及氮肥利用率的影响,为巢湖流域坡岗地区氮肥的减量施用提供依据。结果表明:在巢湖流域坡岗地区中高肥力水平土壤上减少30%的常规施氮量、中低肥力水平土壤减少10%的常规施氮量,虽然单位面积有效穗数下降,但水稻结实率、每穗粒数和千粒重明显增加,不会造成水稻显著减产。两种肥力水平土壤上,氮素收获指数均以常规施氮量处理最低,减量施肥、分期施氮可以促进氮素从茎、叶、根部向谷粒的转移;减量施肥,中高肥力土壤上氮素回收率提高9.99～16.52个百分点,中低肥力水平土壤上提高6.0～12.15个百分点。

Effects of Lower Fertilizer on Rice Growth and Nitrogen Use Efficiency

Field experiments were carried out in slop land area near Chaohu Lake Basin to study rice growth and fertilizer use efficiency of reducing nitrogen application rate throughout the entire rice growing season with the purpose of providing the farmers with scientific basis in promoting reduction of nitrogen application rate.Results showed that reduced nitrogen application rate by 30% in middle-high fertility paddy soil,20% in middle-lower fertility paddy soil rice yield didn’t reduce significantly.The reason is that reduced nitrogen application rate and applied nitrogen in different growth stages could increase filled grain number per panicle and 1000 grain weight,compared with the treatment applied all the nitrogen as basal fertilizer.Nitrogen harvest index of the treatment with current nitrogen application rate was the lowest.Reduced nitrogen application rate and applied nitrogen in different growth stages could promote nitrogen transformation from stem,leave and root to grain in different fertility soils.Reduced nitrogen application rate could increase nitrogen use efficiency by 9.99-16.52 percentage points in middle-high fertility paddy soil,6.0-12.15 percentage point in middle-lower fertility paddy soil.