有机肥和炭基肥替代化肥对甘薯坡耕地径流氮磷损失的影响

Effects of substituting organic fertilizer and biochar-based fertilizer instead of chemical fertilizer on nitrogen and phosphorus runoff loss in sweet potato sloping farmland

【目的】探讨施用有机肥和炭基肥对甘薯Ipomoea batatas坡耕地土壤氮磷径流流失量及形态的影响,探索径流养分流失量和土壤化学性质之间的关系【方法】采用随机区组设计,共设置4种施肥处理:不施肥、常规化肥、50%质量分数有机肥+50%质量分数化肥(有机肥50%替代)、炭基肥,在5个时间点测定甘薯坡耕地径流及土壤中不同形态氮磷质量浓度及质量分数,计算氮磷流失量与流失系数。【结果】径流总氮、颗粒态氮、硝态氮和铵态氮质量浓度存在峰值效应,不同径流的产流中有机肥50%替代和炭基肥效应不同。与常规化肥处理相比,有机肥50%替代和炭基肥分别减少了每年总氮径流流失量的48.1%和39.6%,而总磷则降低了26.1%和32.7%。有机肥50%替代和炭基肥处理改变了径流氮磷形态组成,减少了肥料径流流失系数。总氮(R^(2)=0.49)和总磷(R^(2)=0.48)径流流失量与土壤硝态氮呈显著正相关(P<0.05)。土壤有效磷分别能解释总氮和总磷径流流失量的60%和41%。【结论】有机肥50%替代和炭基肥是减少坡耕地养分径流损失的有效措施,有机肥50%替代更适合用于减少甘薯坡耕地径流氮流失,而炭基肥更适用于减少径流磷流失。图7表2参33。

[Objective]This study aims to explore the effects of applying organic fertilizer and biochar-based fertilizer instead of chemical fertilizer on the amount and form of soil nitrogen and phosphorus loss from runoff in the sloping farmland of sweet potatoes(Ipomoea batatas),and to analyze the relationship between nutrient runoff loss and soil chemical properties.[Method]A randomized block design was used to investigate the effects of organic fertilizer and biochar-based fertilizer on nitrogen and phosphorus runoff loss in sweet potato sloping farmland.There were 4 treatments:no fertilizer,conventional fertilizer,50%organic fertilizer instead of chemical fertilizer,and 100%biochar-based fertilizer.[Result]The concentration of total nitrogen,particulate nitrogen,nitrate-nitrogen,and ammonium-nitrogen in runoff had a peak effect,and the effect of organic fertilizer substitution and biochar-based fertilizer differed in different runoff events.Compared with conventional chemical fertilizer,organic fertilizer and biochar-based fertilizer reduced the annual nitrogen runoff loss by 48.1%and 39.6%,respectively,while total phosphorus decreased by 26.1%and 32.7%,respectively.The substitution of organic fertilizer and biochar-based fertilizer for chemical fertilizer changed the form and composition of nitrogen and phosphorus in runoff and decreased the runoff loss coefficient of fertilizer.The loss of total nitrogen(R^(2)=0.49)and total phosphorus(R^(2)=0.48)was positively correlated with soil nitrate-nitrogen(P<0.05).Soil available phosphorus explained 60%and 41%of total nitrogen and total phosphorus runoff loss,respectively.[Conclusion]Applying organic fertilizer and biochar-based fertilizer instead of chemical fertilizer are effective measure to reduce nutrient runoff loss in sloping farmland.50%organic fertilizer is more suitable for reducing nitrogen runoff loss in sweet potato sloping farmland,while biochar-based fertilizer is more suitable for reducing phosphorus runoff loss.[Ch,7 fig.2 tab.33 ref.]