基于定位试验监测的三种施肥方式对稻田灰水足迹的影响

Effects of Three Fertilization Types on Grey WaterFootprint in Paddy Fields Based on Field Experimental Data

灰水足迹(GWF)方法是定量评价农业生产过程对水环境影响的有效途径。传统的作物生产灰水足迹计算通常采用粗略的估算方法,无法精确量化施肥类型导致的灰水足迹差异。通过田间试验观测常规施肥(CF)、炭基肥(BF)和有机肥部分替代化肥处理(OF)下稻田的水肥迁移过程,识别各径流事件的关键污染物,探讨不同施肥类型下GWF的变化。结果表明:(1)与CF处理相比,BF处理和OF处理均减少了总氮、硝态氮、铵态氮、总磷污染物的流失量,且分别增产3.48%和6.81%。(2)研究期内发生的所有径流事件中,总氮成为关键污染物的频率最大,总磷在某些情形下也是关键污染物,决定灰水产生量的关键污染物具有变异性。(3)肥料类型显著影响水稻生长过程中产生的GWF值,均表现为CF(622.85 m^(3)·t^(-1))> BF (367.68 m^(3)·t^(-1))> OF(318.18 m^(3)·t^(-1))。有机肥部分替代化肥降低了水稻生产灰水足迹且提高了产量,能较好的实现减污增产。基于试验的作物生产灰水足迹计算方法能够准确定量不同施肥类型对灰水足迹的影响。

Grey water footprint(GWF)can be used as an indicator to quantitatively evaluate the impact of agricultural production process on water environment.Traditional methods for calculating GWF of crop production are usually based on rough estimation,which cannot accurately quantify the difference between GWFs caused by fertilizer types.In this study,field experiments were conducted to observe the migration process of water and fertilizer in paddy field under conventional fertilization(CF),biochar-based fertilizer(BF)and organic fertilizer partially replacing chemical fertilizer(OF)treatments.This study aimed to identify the most critical pollutants for each runoff event and to explore the changes in the GWF under different fertilization types.The results showed that:(1)Compared with CF treatment the BF treatment and OF treatment both reduced the pollutant losses of total nitrogen,nitrate nitrogen,ammonium nitrogen and total phosphorus,and increased rice yields by 3.48%and 6.81%,respectively.(2)In all runoff events produced during the study period,the occurring frequency of total nitrogen as the key pollutant was the highest,while total phosphorus was also critical pollutants under certain circumstances,implying that the key pollutant determining the amount of grey water was variant.(3)The impacts of fertilizer typeson the GWF of rice production were in the order of:CF(622.85 m^(3)/t)>BF(367.68 m^(3)/t)>OF(318.18 m^(3)/t).OF reduced the grey water footprint of rice production and increased the rice yield,which help achieve the goal of pollution reduction and yield increase.The method for calculating GWF of crop production based on field measurements can accurately quantify the influence of different fertilizer types on grey water footprint.