单嘧磺隆对土壤呼吸脱氢酶和转化酶活性的影响

Effects of Monosulfuran on Respiration,Hydrogenase and Invertase Activity in Soil

通过室内培养研究了不同浓度单嘧磺隆对土壤呼吸强度和土壤脱氢酶活性、转化酶活性的影响。结果表明,单嘧磺隆的影响随单嘧磺隆浓度和作用时间的不同而异,田间推荐剂量下单嘧磺隆对土壤呼吸强度、土壤脱氢酶活性和转化酶活性没有显著持续不良影响。低浓度单嘧磺隆(<0.8μg·g-1)在试验初期轻微刺激土壤微生物的活性,随培养时间延长刺激作用消失;高浓度单嘧磺隆(>4.0μg·g-1)在试验初期显著抑制土壤微生物活性,对土壤呼吸强度的抑制率最高为26.55%,培养12d以后抑制作用消失,土壤呼吸强度恢复到对照水平。极高浓度单嘧磺隆(25μg·g-1)显著抑制土壤转化酶和脱氢酶活性,在25d试验周期内抑制率分别为5.53%～51.72%和16.06%～21.76%。田间推荐剂量单嘧磺隆(0.025μg·g-1)对土壤转化酶有短暂的抑制作用,最高抑制率为20.23%,对脱氢酶没有明显影响。0.25和2.5μg·g-1单嘧磺隆在试验不同时期对土壤酶活性有轻微刺激作用或抑制作用。第8d时,单嘧磺隆显著抑制土壤转化酶活性,且抑制作用和单嘧磺隆浓度表现出正相关(r=0.95),试验结束时单嘧磺隆的影响减弱。

Effects of monosulfuron, a novel sulfonylurea herbicide, on respiration, hydrogenase and invertase activity of the soil were studied in lab. In the treatments of 0.16 and 0.8μg·g^-1, a slightly stimulative effect on soil respiration was observed at early stage of the experiment （0-7 days） and the effect disappeared afterwards. High concentrations of monosulfuron （higher than 4.0μg·g^-1） inhibited activity of soil microorganisms significantly and the highest inhibition percentage of carbon dioxide emission was as much as 26.55%. The soil respiration activity recovered after incubation for 12 days. In the treatment of 25μg·g^-1, an obvious inhibition on soil invertase and hydrogenase was observed, and the inhibition percentage of enzyme activity was 5.53%-51.72% and 16.06%-21.76%, respectively. The treatment of 0.025μg·g^-1 monosulfuron inhibited the activity of invertase in the early stage （the inhibition percent was as much as 20.23%）, but had no effect on hydrogenase. In the treatments of 0.25 and 2.5μg·g^-1, the activity of the enzymes were inhibited or increased during different period of test. Monosulfuron inhibited invertase activity obviously on the 8th day, and there was a positive correlation with the dosage of monsulfuron （r=0.95）. The influence of monosulfuron decreased at the end of the experiments. It is therefore concluded that the herbicide monosulfuron in normal use may not cause persistent and significant effect on respiration and activity of invertase and hydrogenase of the soil.