腐植酸对土壤氮素转化及氨挥发损失的影响

The influence of humic acid on soil nitrogen transformation and ammonia volatilization losses

采用培养试验方法研究腐植酸添加量(0、5%、10%、25%、50%、75%HA)对土壤氮素转化及其损失的影响。结果表明:与CK对比,1)腐植酸可显著降低氨挥发量,各处理平均降低12.08%,且随着腐植酸添加量的增加对氨挥发的抑制作用增大;2)培养前期,5%~50%添加量范围内腐植酸能提高土壤脲酶活性,至5 d时平均提高了35.13%,75%腐植酸添加量的土壤脲酶活性降低了13.23%,但培养后期(14 d后)腐植酸处理均能提高土壤脲酶活性;3)添加腐植酸使土壤铵态氮含量增加,且随着腐植酸添加量的增大,土壤铵态氮含量呈增加趋势,至培养112 d时,腐植酸处理的土壤铵态氮含量平均增加了39.63%;4)在整个培养期间,腐植酸处理的土壤表观硝化率平均降低了17.20%,且腐植酸的添加量越大,土壤表观硝化率越低。这些结果充分表明腐植酸能够调控土壤氮素去向、减少氮素损失,对提高氮肥利用率具有重要意义。

An incubation experiment was conducted to study the effects of different amounts of humic acid（0,5%,10%,25%,50%,75% HA） on soil nitrogen transformation and ammonia volatilization losses. The results showed that compared with control,1） humic acid reduced ammonia volatilization significantly by an average of 12. 08%,meanwhile,the more humic acid added,the greater inhibitory effect showed on ammonia volatilization. 2） In the prophase of cultivation,the 5% ~50% humic acid improved the soil urease activity and the average increase was 35. 13% at the fifth day,but 75% humic acid decreased soil urease activity by 13. 23%,then enhanced it in the later period of incubation（14 ndday）. 3） Humic acid increased soil ammonium nitrogen content,the increases were enhanced with the increase of humic acid adding proportions. The content of ammonium nitrate treated with humic acid increased averagely by 39. 63% at the 112 ndday. 4） During the whole culture period,the soil apparent nitration of humic acid treatments decreased by 17. 20% averagely,and the higher the amount of humic acid,the lower the soil apparent nitration rate. These results have important significance to reveal the role of humic acid in the regulation of soil nitrogen,reduce nitrogen loss and increase the utilization efficiency of nitrogen fertilizer.