The interaction effect of two sulfonylurea herbicides, bensulfuron methyl (B) and metsulfuron methyl(M), were tested on microbial biomass C, N, N mineralization and C/N ratio in a loamy sand soil. The herbicides we...The interaction effect of two sulfonylurea herbicides, bensulfuron methyl (B) and metsulfuron methyl(M), were tested on microbial biomass C, N, N mineralization and C/N ratio in a loamy sand soil. The herbicides were applied at various levels of: control (B0M0), 0.01 and 0.01 (B1M1), 0.01 and 0.1 (B1M2), and 0.01 and 1.0 (B1M3) μg/g soil. Determinations of soil microbial biomass C, N and N mineralization contents were carried out at 1, 3, 5, 7, 10, 15, 25 and 45 days after herbicides application. The results showed that the soil microbial biomass C (C mic ) and microbial biomass N (N mic ) decreased consistently with the increasing rates of herbicides. The results further indicated that B1M1 and B1M2 caused a significant reduction in C mic and N mic within first 10 and 7 days of incubation, respectively, as compared with the control. These reductions in C mic and N mic were also significant ( P =0.05) with B1M3 application especially within first 15 days of incubation. A significant reduction in N mineralization (N min) was observed with high doses (B1M2, B1M3) of herbicides within first 5 days of incubation, while low rate (B1M1) failed to produce any significant effect. An increase in the soil microbial biomass C:N ratio was also noted.展开更多
实验室培养条件下 ,研究了14 C 甲磺隆在 7种不同类型土壤中形成结合残留( 14 C BR)的规律、主要影响因子及14 C BR在腐殖质中的动态分布规律等。结果表明 :( 1 ) 14 C 甲磺隆在 7种土壤中形成的14 C BR含量在培养初期的 2 0d内与土壤p...实验室培养条件下 ,研究了14 C 甲磺隆在 7种不同类型土壤中形成结合残留( 14 C BR)的规律、主要影响因子及14 C BR在腐殖质中的动态分布规律等。结果表明 :( 1 ) 14 C 甲磺隆在 7种土壤中形成的14 C BR含量在培养初期的 2 0d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 2 0d后 ,14 C BR含量只与土壤pH呈显著负相关。土壤pH是14 C 甲磺隆在土壤中形成BR的主要影响因子。14 C -甲磺隆在各类土壤中的14 C BR的最大值分别占引入量的 48 5%、46 5%、52 6%、1 9 3 %、49 7%、42 0 %和 46 5% ;( 2 )在整个培养试验过程中 ,14 C 甲磺隆在 7种不同类型土壤中的14 C BR ,主要分布在富啡酸和胡敏素中 ,前者中的相对百分比大于后者 ,而在胡敏酸中的相对百分比较小。土壤中14 C 甲磺隆BR的形成过程中 ,富啡酸的作用 >胡敏素展开更多
基金TheNationalKeyBasicResearchDevelopmentandPlanningofChina (No .G19990 1180 9) TheNationalNaturalScienceFoundationofChina (No .
文摘The interaction effect of two sulfonylurea herbicides, bensulfuron methyl (B) and metsulfuron methyl(M), were tested on microbial biomass C, N, N mineralization and C/N ratio in a loamy sand soil. The herbicides were applied at various levels of: control (B0M0), 0.01 and 0.01 (B1M1), 0.01 and 0.1 (B1M2), and 0.01 and 1.0 (B1M3) μg/g soil. Determinations of soil microbial biomass C, N and N mineralization contents were carried out at 1, 3, 5, 7, 10, 15, 25 and 45 days after herbicides application. The results showed that the soil microbial biomass C (C mic ) and microbial biomass N (N mic ) decreased consistently with the increasing rates of herbicides. The results further indicated that B1M1 and B1M2 caused a significant reduction in C mic and N mic within first 10 and 7 days of incubation, respectively, as compared with the control. These reductions in C mic and N mic were also significant ( P =0.05) with B1M3 application especially within first 15 days of incubation. A significant reduction in N mineralization (N min) was observed with high doses (B1M2, B1M3) of herbicides within first 5 days of incubation, while low rate (B1M1) failed to produce any significant effect. An increase in the soil microbial biomass C:N ratio was also noted.
