太湖流域典型桃园土壤氮素径流流失特征

为探索协调水蜜桃优质高产与桃园养分合理投入的技术途径,以12年生晚湖景桃树为供试材料,通过野外大田小区试验(2012—2013年),研究了自然降雨条件下不同施肥及桃园管理模式对太湖流域典型水蜜桃园土壤氮素径流流失特征的影响。结果表明:农户习惯性施肥(T1)条件下,径流水TN浓度最高达87.72mg/L,且随生育期呈现总体降低趋势。减量施肥(T2)和生草模式(T3)显著降低全生育期内11次径流过程的平均TN浓度,且分别达26.16%和12.89%。桃园全生育期径流水TN流失总量达52.06kg/hm2,径流流失率达6.21%,主要分布于桃果座果期到果实成熟期和果实采收后的强台风季。生草模式(T3)显著降低TN径流流失量和流失率,且分别达7.41%和7.41%,减量施肥(T2)处理显著减少TN径流流失量,达26.96%,而流失率却增加3.99%,处理间差异不显著。同时,生草模式(T3)和减量施肥(T2)处理均可显著降低桃园土壤氮素偏流失率,降幅分别达9.51%和20.70%。

Characteristics of Nitrogen Losses by Surface Runoff in a Typical Peach Orchard Field in Taihu Lake Basin, China

Within an orchard containing 12-year-old late-maturing peach trees (cultivar Hujing) in Taihu Lake Basin,China,different fertilizer application rates and management practices were applied to explore the technological approaches to coordinate high quality and high yield of peach during 2012-2013.The effects of these treatments on soil nitrogen loss by surface runoff in the typical peach orchard were investigated under natural rainfall conditions.In T1 (conventional fertilization practice),total nitrogen concentration (TN)in the surface runoff water reached the peak value of 87.72 mg/L,and TN showed a decreasing trend with the peach growth period.Compared with T1,T2 (reducing fertilization practice to 70％ of conventional) and T3 (Inter-planting white clover (Trifolium repens L.)) significantly reduced the average TN in whole peach growth period,which decresed by 26.16％ and 12.89％,respectively.In T1,the quantity and coefficient of TN losses by surface runoff reached up to 52.06 kg/hm2 and 6.21％,respectively;these mainly occurred from the peach fruit setting stage to the peach fruit ripening stage,and the strong typhoon season after peach fruit harvest.Compared with T1,T3 significantly reduced the quantity and coefficient of TN losses by 7.41％ and 7.41％,respectively.T2 significantly reduced the quantity of TN losses by 26.96％,but TN loss coefficient slightly increased by 3.99％.Furthermore,compared with T1,T3 and T2 significantly reduced the partial coefficient of TN losses by surface runoff by 9.51％ and 20.70％,respectively.