Factors Affecting the Loss of Tri‐allate From Soils

Summary. Electron‐capture gas chromatography was used to detect tri‐allate residues in persistence studies with two soils. At rates equivalent to 0–75, 15 and 3 Ib/ac, 50% of the amount applied was degraded in 8–11 weeks at 25°C in moist Regina heavy clay and Weyburn loam. No loss occurred in sterile soils, indicating that microbial degradation may be a, major factor contributing to tri‐allate breakdown. When aqueous solutions buffered at pH 4–8 were held at 25° G, only 10–15% of the tri‐allate was chemically degraded during 24 weeks. At the normal field rate of 1·25 Ib/ac, tri‐allate was not readily leached. From soil columns of Weyburn loam, 5–7% was eluted by 9 in. of water; with clay the corresponding value was 12–13% of the amount applied. When field plots were sprayed with 125 lb/ac in April, tri‐allate could still be detected until the soil froze in November. Facteurs agissant sur la perte de tri‐allate dans les sots