DYNAMICS OF NEMATICIDE DISTRIBUTION AND DEGRADATION IN SOIL SUBJECTED TO LONG-TERM PINEAPPLE CULTURE
Environmentally safe and efficacious use of nematicides requires detailed understanding of their soil environmental chemistry. This is exemplified for 1,3-dicloropropene [1,3-D] use in soil subjected to long-term pineapple culture. 1,3-D degradation and distribution among soil phases was determined in Wahiawa silty clay [clayey kaolinitic isohyperthermic Tropeptic Eutrustox] from Hawaii during a closed system laboratory incubation study. A nominal application of 100 μg 14C-1,3-D (1:1 ratio of cis to trans isomer) per g soil oven dry equivalent was introduced by subsurface injection to soils maintained at -100 kPa and 25°C. Degradation and distribution of 1,3-D among available, labile, and bound phases was monitored for up to 44 days. In the A-horizon soil, 1,3-D exhibited rapid Monod decay; 34% of applied 14C was present as 14CO2 and an additional 38% of applied 14C was associated with the baserecalcitrant bound phase [soil humus] after 22 days. In the B-horizon soil 1,3-D degradation was pseudo first-order; 45% of applied 14C was present as available 1,3-D after 22 days. 3Chloroallyl alcohol, the product of 1,3-D hydrolysis, accumulated to significant levels with incubation in B-horizon soil; but it never exceeded trace levels in A-horizon soil where 1,3-D was rapidly mineralized. Biologically-mediated degradation of 1,3-D influences the phase partitioning of 1,3-D and its degradates and, thus, is an important parameter governing efficacy and environmental fate in the soil system.
Wolt, J.D., Holbrook, D.L., Batzer, F.R., Balcer, J.L. and Peterson, J.R. (1993). DYNAMICS OF NEMATICIDE DISTRIBUTION AND DEGRADATION IN SOIL SUBJECTED TO LONG-TERM PINEAPPLE CULTURE. Acta Hortic. 334, 361-372