ISHS Acta Horticulturae 334: I International Pineapple Symposium
DYNAMICS OF NEMATICIDE DISTRIBUTION AND DEGRADATION IN SOIL SUBJECTED TO LONG-TERM PINEAPPLE CULTURE |
| Authors: | J.D. Wolt, D.L. Holbrook, F.R. Batzer, J.L. Balcer, J.R. Peterson |
| Abstract:
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. | |
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