氟乐灵在土壤中的结合残留及其对作物的影响

介绍了除草剂氟乐灵在两种土壤中可提部分的消失动态,研究了土壤组分、水分状况及微生物活性对~(14)C-氟乐灵结合残留形成的影响,以及土壤中结合残留物对小麦、黑麦草的有效性.结果表明,有机质含量高的黑土能结合较多的~(14)C-残留物.对含结合残留物的土壤进行高温馏出处理,馏出物的GC检定结果显示除少量母体结构外,氟乐灵主要是通过其代谢物与土壤结合的.盆栽试验表明,氟乐灵结合残留对农作物的生长有明显抑制.

BOUND RESIDUE OF TRIFLURALIN IN SOIL AND ITS BIOAVAILABILITY TO PLANTS

Disappearance dynamics, formation of bound residue of herbicide triflu-ralin in various soils (paddy soil and phaeozem) and factors influenced level of bound residue in soil were investigated. The results showed that the residues could be incorporated into organic or mineral composition of soil to produce bound residue by biological or abiotic processes. Contents of organic or clay, incubation condition (aerobic or waterlogged) and microbial activity would effect the capacity of soil binding the chemical. Phaeozem which contains more organic matter and clay could bind more pesticide residues; waterlogged condition contributed to biotic incorporation and aerobic condition accelerated abiotic incorporation. The amount of 14C-bound residue in soil increased with incubation time, more than 20% found to be bound. GC of the distillation products of soil samples containing bound residue by high temperature distillation technique (HTD) showed that along with small amount of parent compound, they were mainly composed of some metabolites. It seems that trifluralin bound residue in soil was mainly formed through the incorporation of the lowly stearic hindered reductive derivatives of aniline into soil compositions. Results of pot experiments showed that the bound residue level in the soil cultured crop (soybean) was lower (1.18% of dose) than that in the soil noncultured crop (2.25% of dose). It was also found that bound residue in soil could be uptaken by plants (wheat and rye-grass), and specific intensities of 14C in plants were directly proportional to bound residue levels in soil (except stem sample of rye-grass).