| 14C-甲磺隆在土壤中的可提态残留、结合态残留和矿化 |
| 摘要点击 1833 全文点击 1233 投稿时间：2002-02-09 修订日期：2002-06-28 |
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| 中文关键词 14C-甲磺隆 结合残留 可提态残留 矿化 土壤 |
| 英文关键词 14C-metsulfuron-methyl extractable residue bound residue distrbution soil |
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| 中文摘要 |
| 在实验室培养条件下,从质量平衡角度,研究了14C-甲磺隆在7种土壤中形成结合残留(14C-BR)、可提态残留(14C-ER)以及矿化为14CO2的规律;同时对14C-BR的主要影响因子及其在腐殖质中的分布规律进行了研究.结果表明:①14C-甲磺隆在土壤中形成的14C-ER,其含量与土壤pH呈显著正相关.甲磺隆母体化合物在7种土壤中 的半减期为13.3～66.6d,降解速率常数λ(d-1)与pH呈显著负相关.②14C-甲磺隆在7种土壤中形成的14C-BR,其含量在培养初期的20d内,与土壤pH呈显著负相关且与土壤粘粒含量呈显著正相关;而培养20d后,14C-BR的含量只与土壤pH呈显著负相关.pH是14C-甲磺隆在土壤中形成BR的主要影响因子.14C-甲磺隆在7种土壤中的14C-BR的最大值约为引入量的19.3%～52.6%.③在整个培养试验过程中,7种土壤中的14C-BR主要分布在富啡酸和胡敏素中,但其分布在胡敏酸中的相对百分比较小.因此,在14C-甲磺隆形成BR的过程中,富啡酸的作用＞胡敏素>胡敏酸.④在整个培养试验期间(180d),14C-甲磺隆在7种土壤中通过三嗪杂环开环矿化为14CO2的量约占引入量的12.9%～27.0%,其在碱性土壤中更难被矿化为14CO2. |
| 英文摘要 |
| The purpose of the present study was to investigate 14C-extractable residue(14C-ER),14C-bound residue(14C-BR)and mineralization of 14C-labeled metsulfuron methyl in soils. The main factors affecting 14C-BR formation and the distribution pattern of 14C-BR in humus were also discussed in details. The results were as follows: (1) The total 14C-ER content of 14C-metsulfuron methyl in seven kinds of soil was positively related to soil pH and negatively related to clay content significantly during the initial 20 days of incubation, however, only positively relation to soil pH was found after 30 days of incubation. Moreover, the half life values of 14C-metsulfuron methyl parent compound derived from 14C-ER in soils tested ranged from 13.3 to 66.6 days. The degradation rate coefficient λ (day-1) was negatively related to soil pH. (2) The 14C-BR content of 14C-metsulfuron methyl in soils was significantly negatively related to soil pH and positively related to the clay content during the initial 20 days of incubation, but only was significantly negatively related to soil pH after 30 days incubation. Again, the soil pH was found to be the dominant factor affecting BR formation of 14C-metsulfuron methyl among the basic properties of soil. The maximum content of 14C-BR of 14C-metsulfuron methyl in the soils accounted for 19.3%～52.6% of applied amount (3) During the whole periods of the incubation, the 14C-BR of 14C-metsulfuron methyl in the soils was found to be mainly associated with fulvic acid and humin. The relative percentage of 14C-BR in fulvic acid was higher than in humin, while the content of the 14C-BR distributed in humic acid only account for less than 1% of applied amount. Therefore, fulvic acid played an important role in the process of BR formation of 14C-metsulfuron methyl. (4) About 12 9%～27 0% of applied amount of 14C-metsulfuron methyl was mineralized to 14CO2 through opening 14C-triazine ring in soils tested after 180 days of the incubation. It was difficult for 14C-metsulfuron methyl to mineralize to 14CO2 in an alkaline soil. |
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