在蔬菜作物生长期中二硫氰基甲烷和四硫代碳酸钠处理根围土壤的安全性和效果研究

The pest-controlling efficacy and safety of treating rhizosphere soils with methylene bisthiocyanate and sodium tetrthiocarbonate in growing period of vegetable crops

采用实验室平皿法测试了二硫氰基甲烷(MBTC)对几种蔬菜种子萌发和发育的影响。结果显示:MBTC浓度<50μg/mL时,黄瓜、青菜、豇豆和菜豆均能正常萌发;MBTC浓度为12.5～25.0μg/mL时表现出促进生长作用;MBTC浓度>100μg/mL时则严重抑制萌发甚至死亡,对MBTC的耐药性依次为豇豆>青菜>黄瓜>菜豆。MBTC和四硫代碳酸钠(STTC)在上述蔬菜和几个多年生草本作物(草莓、苜蓿和酢酱草等)生长期中进行漫灌和穴灌根围土壤处理的田间试验结果显示:10%MBTC稀释液浓度为有效成分35～50μg/mL,31.5%STTC稀释液浓度为有效成分600～800μg/mL,施药15 d后,黄瓜、番茄、豇豆、菜豆和几种多年生作物均表现安全,生长良好;土壤中线虫数量降低67.7%～90.4%,真菌密度降低80%～90%。

Effects of methylene bisthiocyanate（MBTC） on the seed germination and development of cucumber,Chinese cabbage,cowpea and snap bean were tested by the plating method in laboratory. The results showed that MBTC at less than 50μg/mL did not affect the 4 vegetable crops＇seeds to germinate normally,and MBTC at 12.5～25.0μg/mL had an accelerating effect on their growth,but MBTC at more than 100μg/mL inhibited the seeds to germinate and even made them die.The descending order of the 4 vegetable crops in chemical tolerance was cowpeaChinese cabbagecucumbersnap bean.The field experiments with the above 4 vegetable crops and such perennial herbs as strawberry, alfalfa and red woodsorrel showed that in the growing period of the plants,flooding irrigation and hole irrigation with 10%MBTC（SL） at 35～50（ai）μg/mL and 31.5%sodium tetrathiocarbonate （SL） at 600～800（ai）μg/mL were safe for all the tested plants to grow,and the densities of nematodes and fungi in the soil were reduced by 67.7%～90.4%and 80%～90%,respectively.