| 摘要: |
| 分别用测定残留尿素（直接法）和矿质氮累积量（间接法）的方法，测定了土壤的尿素水解速率，并比较通气培养和淹水培养期间尿素水解的异同。结果表明：虽然这两种方法在反映土壤脲酶活性和尿素水解速率上有相同趋势，但直接法测定的结果显著高于间接法。用直接法测定尿素水解速率，既不考虑水解产物的转化，也不考虑氮素损失，因此，具有矿化量法难以比拟的优点。用通气培养法测定的尿素水解速率虽然极显著地高于淹水培养，但两者之间仍呈高度正相关，说明它们在表征土壤尿素水解状况上有相似趋势。对旱地土壤，通气培养法更切合实际。培养期间加入甲苯，使尿素水解速率大幅度增加。 |
| 关键词: 土壤，尿素水解速率，残留尿素，矿质氮累积 |
| DOI： |
| 分类号:S151.9 |
| 基金项目:国家自然科学基金与黄土高原土壤侵蚀和旱地农业国家重点实验室基金资助项目 |
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| Differences of Urea Hydrolysis Rates under Several Determination Conditions |
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Li Shiqing Li Shengxiu
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| Abstract: |
| Two methods,one for determing residual urea (RU) and one for determing mineral nitrogen accumulation (MNA) were used for measuring urea hydrolysis rates in soils,and a comparison of the results was made under aerobic and waterlogged incubation conditions.The results obtained indicated that the urea hydrolysis rates by MRU were significantly higher than that by MNA although the urea hydrolysis rates by toth methods were well correlated.This difference was mainly caused by clay mineral fixation of 4+ produced in hydrolyzing process of urea.Considering neither transformation of hydrolyed product nor loss of nitrogen,the RU method is superior to the MNA one.In addition,the urea hydrolysis rates estimated by aerobic incubation were higher than those did by waterlogged incubation.However,a good agreement was obtained between aerobic and waterlogged incubation.These results suggested that both incubation methods could provide similar information on estimation of urease activity and urea hydrolysis rate.As a whole,the aeobic incubation method is more suitable for dryland soils than the waterlogged.Applied to toluence during incubation,the urea hydrolysis rates could significantly increase. |
| Key words: soil,urea hycrolysis rate,residual urea,mineral nitrogen accumulation |
