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在砂土和黏土两种土壤类型上,研究了施氮量对田面水NH4+-N浓度、氨挥发损失量、水稻产量、氮肥利用效率和土壤剖面氮素含量的影响。施氮后田面水NH4+-N浓度和氨挥发量都随着施氮量的增加而增加,且在施氮后1～3 d达到峰值,黏土要低于砂土;氨挥发损失量为分蘖肥时期>倒4叶穗肥期>基肥时期>倒2叶穗肥期;黏土上稻季氨挥发总损失量为10.49～87.06 kg/hm2,占施氮量的10.92%～21.76%;砂土上稻季氨挥发总损失量为11.32～102.43 kg/hm2,占施氮量的11.32%～25.61%;施氮后氨挥发峰值和田面水铵态氮峰值同步出现,以分蘖肥时期最大,两者比值范围为23.76%～33.65%;随着施氮量的增加,水稻产量增加,氮素积累量也增加,而氮肥利用效率降低;黏土上的水稻产量和氮素积累量要略高于砂土上的;土壤氮素含量在土壤深度40～50 cm处最低,相应各层土壤氮素含量随着施氮量的增加而提高,黏土要高于砂土。从氨挥发损失的角度来看,当施氮量超过250 kg/hm2时,氨挥发损失总量将跃增;而从水稻获得高产的角度来看,施氮量应为300 kg/hm2左右,因此,试验条件下水稻高产且环境安全的适宜施氮量为250～300 kg/hm2。
Effects of nitrogen rate on NH4 + -N concentration, ammonia volatilization loss, rice yield, N use efficiency and soil nitrogen profile in field profile were studied on two soil types, sand and clay. NH4 + -N concentration and NH3 volatilization of surface water increased with the increase of N application rate after nitrogen application, and reached the peak 1 ~ 3 days after application of nitrogen, the content of clay was lower than that of sand soil; the amount of ammonia volatilization loss was tillering fertilizer Period> inverted 4-leaf panicle stage> basal stage> inverted 2-leaf stage. The total amount of volatilization of rice in quaternary ammonium was 10.49 ~ 87.06 kg / hm2, accounting for 10.92% ~ 21.76% The total amount of ammonia volatilization in rice season was 11.32 ~ 102.43 kg / hm2, accounting for 11.32% ~ 25.61% of the amount of nitrogen application. The peak of ammonia volatilization appeared synchronously with the NH4 (superscript - With the range of 23.76% -33.65%. With the increase of nitrogen application, the yield of rice increased, the nitrogen accumulation also increased, but the nitrogen use efficiency decreased. The yield of rice and nitrogen accumulation on clay were slightly higher than that of sand . The soil nitrogen content was the lowest at the soil depth of 40 ~ 50 cm. The soil nitrogen content of the corresponding layers increased with the increase of nitrogen application rate, and the clay content was higher than that of sand. From the viewpoint of ammonia volatilization loss, the total ammonia volatilization loss will increase when the nitrogen application rate exceeds 250 kg / hm2. From the point of view of obtaining high yield from rice, the nitrogen application rate should be about 300 kg / hm2, Therefore, the optimal nitrogen application rate for rice with high yield and environmental safety under the experimental conditions is 250-300 kg / hm2.