Effects of organic fertilizer nitrogen replacement ratio on nitrogen use efficiency and ammonia volatilization of double-crop rice
The study aimed to effectively prevent and control the loss risk of ammonia(NH3)volatilization and improve the utilization efficiency of nitrogen(N)fertilizer in rice.Organic fertilizer N was set to replace chemical fertilizer N with six different replacement ratios:0%(ON0),10%(ON0.1),20%(ON0.2),30%(ON0.3),50%(ON0.5),80%(ON0.8)and a control treatment(no N,CK).Field experiment was conducted using the closed chamber intermittent ventilation method to study the effects of different organic N replacement ratio on the seasonal variation of soil NH3 volatilization rate and its loss characteristic,and N fertilizer utilization efficiency in double-cropping rice field.The results showed that N fertilizer absorption and utilization ratio,N fertilizer agronomic utilization ratio,N fertilizer partial productivity and N harvest index of rice first increased and then decreased with the increase of organic fertilizer N substitution ratio,and the N fertilizer utilization ratio of early rice was significantly higher than that of ON0 treatment.The peak value of NH3 volatilization in early-and late-rice fields occurred at 2 to 5 and 1 to 3 d after fertilization,respectively.The highest total volatilization loss(rate)of NH3 was observed under ON0 treatment,which was N 76.18 kg·hm-2(22.38%),during the growing season of double cropping rice.The total volatilization loss(rate)of NH3 in organic N replacement treatments was N 42.26-68.13 kg·hm-2(12.81%-20.65%),which was significantly negatively correlated with the N replacement ratio of organic fertilizer.The NH3 volatilization per unit yield of double cropping rice in organic N replacement treatments was 0.74-2.10 kg·t-1 lower than that in ON0 treatment.The emission reduction effect of organic fertilizer N replaced by 20%-80%treatments in early rice season and by 30%-80%treatments in late rice season reached a significant level.Correlation analysis showed that the total amount of NH3 volatilization had a significant positive correlation with the average NH4+-N concentration of surface water,but had no significant correlation with the average NO3--N concentration and pH.In general,replacing 20%-30%of fertilizer nitrogen with organic fertilizer N could effectively reduce NH3 volatilization in double-cropping rice fields,reduce the risk of N loss,simultaneously promote nutrient absorption,and improve N fertilizer utilization efficiency in rice fields.
double-cropping riceorganic nitrogen replacement rationitrogen use efficiencyammonia volatilization
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NSTL
万方数据
