论文部分内容阅读
为研究深层包气带土壤中氮素的迁移规律,采用田间小区试验,研究了不同施氮水平(142.5、285和427.5kg/hm2)对夏玉米种植期间0～500cm包气带土壤中氮素淋溶累积的影响。结果表明,不同施氮水平对NO3--N、NH4+-N和总氮有显著影响,施氮越多,NO3--N、NH4+-N和总氮在土壤中的淋溶累积也就越多,夏玉米生育期间土壤中氮素的淋溶累积含量随着夏玉米生长逐渐减少。在0～200cm土层中,收获后不同施肥水平土壤中NO3--N和总氮累积量随施氮量增加而增多,285kg/hm2施氮水平NH4+-N累积量最多,427.5kg/hm2施氮水平NH4+-N累积量最少,但相差不超过0.1kg/hm2,收获后土壤中氮素累积量有损失。夏玉米生育期间不同施氮水平对土壤NO3--N、NH4+-N和总氮的影响深度主要为0～145cm。粉砂壤土中氮素更易累积,砂质壤土中氮素较易随水分淋溶至下层。142.5kg/hm2施氮水平可有效减少NO3--N在土壤中的淋溶损失,降低土壤中NH4+-N和总氮的含量,对地下水构成的潜在污染风险最小。北京地区地下水埋深较深,NO3--N不易淋溶至地下水,但长期大量施用氮肥、田间土壤大孔隙的存在等会加速NO3--N向深层土壤迁移,对地下水水质构成威胁。
In order to study the migration of nitrogen in soils with deep aeration zone, a field plot experiment was conducted to study the effects of nitrogen (142.5, 285 and 427.5 kg / hm2) on nitrogen Effect of leaching accumulation. The results showed that different levels of nitrogen fertilizer had significant effects on NO3 - N, NH4 + -N and total nitrogen. The more nitrogen application, the more leaching of NO3 - N, NH4 + -N and total nitrogen in soil The leaching content of soil N in summer maize decreased with the growth of summer maize. In 0 ~ 200cm soil layer, NO3 - N and TN accumulation in different soil fertility levels increased with the increase of N application rate, NH4 + -N accumulation rate of 285 kg / hm2 nitrogen application was the highest, and 427.5kg / hm2 application rate The NH4 + -N accumulation in the nitrogen level was the least, but the difference was no more than 0.1 kg / hm2. The nitrogen accumulation in the soil was lost after harvesting. The effects of different N rates on soil NO3 - N, NH4 + -N and TN during summer maize growth were mainly 0 ~ 145cm. Nitrogen in silty loam soil is more likely to accumulate, while nitrogen in sandy loam soil tends to leach to the bottom with water. The nitrogen application level of 142.5kg / hm2 can effectively reduce the leaching loss of NO3 - N in soil and reduce the content of NH4 + -N and TN in the soil, which has the lowest potential pollution to groundwater. The groundwater depth in Beijing is rather deep, and NO3 - N is not easily leached to groundwater. However, the long - term application of nitrogen fertilizer and the presence of macropores in the soil will accelerate the migration of NO3 - N to deep soil and threaten the groundwater quality.