Plant availability of bound anilazine residues in a degraded loess soil
The relative biological availability of benzene ring-U-/sup 14/C and triazine-U-/sup 14/C anilazine for maize plants was studied in a degraded loess soil in a standardized microecosystem. The total uptake of radiocarbon in the course of the 4-week experiment was 3.1 and 4% respectively of the radioactivity applied if anilazine was uniformly mixed into the soil immediately before beginning the experiment. However, if anilazine was subjected to a degradation at 65% of the maximum water holding capacity of the soil and temperatures varying daily between 16 and 27/sup 0/C for 100 days before the plant experiment then the uptake was reduced to 0.4 or 0.7% respectively. The uptake from soil with non-extractable (bound) anilazine residues was similarly low. The mineralization rate of aged and bound anilazine residues was below 0.1% of the radioactivity applied. Up to 2/3 of the radioactivity present in the soil after the plant experiment remained in the humic fraction.