不同施氮水平对库尔勒香梨园土壤氨挥发损失的影响

Effects of different nitrogen application levels on soil ammonia volatilization loss in Korla fragrant pear orchard

为探究不同施肥处理对库尔勒香梨园土壤氨挥发的影响,选取6年生库尔勒香梨树为研究对象,在香梨年生育期内,设置了不施肥(N_0P_0K_0)、不施氮肥(N_0PK)、低氮量(N_1PK)、中氮量(N_2PK)、高氮量(N_3PK)5个处理,采用密闭式集气法对不同施肥处理的氨挥发进行田间定位测定。结果表明,不同施肥处理氨挥发速率在一天内的表现为:晚上(20:00～08:00)<上午(08:00～12:00)<中午(12:00～16:00)<下午(16:00～20:00)。日积量夜间<白天。不同施肥处理氨挥发年生育期累积量表现为:N_0P_0K_0<N_0PK<N_1PK<N_2PK<N_3PK。温度、灌水、施氮对库尔勒香梨园土壤氨挥发均有显著影响,施氮对库尔勒香梨园土壤的氨挥发影响最大。施氮处理N_1PK、N_2PK、N_3PK的氨挥发年生育期累积量分别为34.94、36.38、44.42 kg·hm^(-2)·年^(-1),氨挥发净损失率分别为4.48%、2.72%、3.60%。N_2PK处理的库尔勒香梨产量最高,达到6 213.50 kg·hm^(-2),且氨挥发净损失率最小,为2.72%。综合生产及环境效益,推荐本区域库尔勒香梨园的最佳施氮量为300 kg·hm^(-2)。

In order to explore the effects of different fertilization treatments on soil ammonia volatilization in Korla fragrant pear orchard,6-year-old korla fragrant pear was selected as the study object.During the growing period of korla fragrant pear,the collection method of closed gas was used to determinate the soil ammonia volatilization of different fertilization treatments,including:the control(N0P0K0),no nitrogen(N0 PK),low nitrogen(N1 PK),medium nitrogen(N2 PK),and high nitrogen(N3 PK).The results showed that the soil ammonia volatilization rate of different fertilization treatments was night(20:00~8:00)<morning(8:00~12:00)<noon(12:00~16:00)<afternoon(16:00~20:00)in a whole day,the diurnal cumulative amount showed nighttime<daytime.The accumulating amount of soil ammonia volatilization of different treatments in annual growth period showed that N0P0K0<N0 PK<N1 PK<N2 PK<N3 PK.Temperature,irrigation and nitrogen application all had significant effects on soil ammonia volatilization in Korla fragrant pear orchard.Nitrogen application had the greatest impact on soil ammonia volatilization.The cumulative amount of soil ammonia volatilization under different nitrogen application rates(N1 PK,N2 PK and N3 PK)were 34.94,36.38 and 44.42 kg·hm-2·a-1 in the annual growth period,respectively,and the net ammonia loss rates were 4.48%,2.72%and 3.60%,respectively.The yield of Korla pear treated with N2 PK was 6 213.50 kg·hm-2,which was the highest among the different nitrogen treatments and the net loss rate of ammonia volatilization was 2.72%,which was the smallest.Considering the comprehensive effects of nitrogen application on the production and environmental benefits,it was recommended that the optimal nitrogen application rate was 300 kg·hm-2 in Korla fragrant pear orchard.