異丙甲草胺對烤煙根際土壤微生物和酶活性的影響

謝穎　陳媞　龍友華　李榮玉　尹顯慧　李明　吳小毛

摘要：為了探明根際微生物數量與除草劑污染之間的關系，研究了異丙甲草胺對煙草植地根際與非根際土壤微生物的種群動態變化、土壤呼吸強度及酶活性的影響。結果表明：根際土壤中微生物數量、土壤呼吸強度和酶活性均高于非根際土壤。根際土壤微生物對異丙甲草胺的敏感程度依次為真菌〉細菌〉放線菌；除過氧化氫酶外，根際土壤脫氫酶、脲酶及磷酸酶的活性與對照土壤均存在顯著差異。第60 d，異丙甲草胺在根際土壤中的降解率為8050%，半衰期為2682d，比在非根際土壤中的降解速率提高了121倍，半衰期縮短了1776%。

關鍵詞：異丙甲草胺；根際；土壤微生物；呼吸強度；酶活性

中圖分類號：S4828+92

文獻標識碼：A

文章編號：1008-0457（2017）02-0013-06國際DOI編碼：10.15958/j.cnki.sdnyswxb.2017.02.003

Abstract：In order to investigate the relationship between the herbicide contamination and the number of microorganisms in plant rhizosphere soil， the effect of metolachlor on the microbial number， the intensity of soil respiration and the enzyme activity in tobacco rhizosphere and non-rhizosphere soils were studied. The results showed that the number of rhizosphere microorganisms， the soil respiration intensity and the enzyme activity were higher in rhizosphere soil than non-rhizosphere soil. The sensitivity of microorganisms to metolachlor in rhizosphere soil was in the order of fungi > bacteria> actinomycetes. Except for catalase， there were significant differences between activities of dehydrogenase， urease and phosphatase in the rhizosphere soil and in the non-rhizosphere soil. At 60th day， the degradation rate of metolachlor was 8050% and its half-life was 2682 day in rhizosphere soil. The degradation rates of metolachlor in rhizosphere soil were 121 times of that in non-rhizosphere soil. The degradation half-life of metolachlor in the rhizosphere soil was 1776% shorter than that in the non-rhizosphere soil.

Key words：metolachlor； rhizosphere； soil microorganism； respiration rate； enzymatic activit

根際環境與根際微生物是植物降解有毒有害有機污染物的基礎，農藥等有機污染物影響下的根際土壤與一般土壤在pH、養分組成狀況、微生物組成、酶活性等存在顯著的差別，這些都直接影響一年生單子葉及部分雙子葉雜草的防除時施用的接影響有機污染物在土壤-植物系統中的遷移和轉化行為[1]。

異丙甲草胺作為持效期較長的酰胺類選擇性芽前除草劑，廣泛使用煙草、水稻、大豆田中一年生單子葉及部分雙子葉雜草的防除[2]。目前，已有異丙甲草胺的研究主要有異丙甲草胺對根際土壤微生物數量的影響及其在根際環境中的降解研究、異丙甲草胺對芹菜根際與非根際生物活性的影響、異丙甲草胺及其高效體對我國南方潮土微生物的影響、異丙甲草胺防除煙地雜草效果評價等，但未見異丙甲草胺對煙地根際微生物及土壤酶活性的影響的相關報道[3-6]。為此……