Temperature Inversions and Off-target Movement of Herbicides
By Richard H. Grant, Ph.D.
Department of Agronomy
West Lafayette, Indiana
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Much of recent off-target dicamba damage is blamed on volatilization, transport and deposition during temperature inversions. Unfortunately it is not possible to easily know if inversion conditions are present. As a result the USEPA has restricted guidelines designed to prevent application during inversions based on winds and time-of-day. Characteristics of inversions in northern Mississippi were explored through an analysis of five years of National Reference Climate Network measurements at Holly Springs, MS. This presentation addresses to answer a set of questions: ‘Do low wind speeds (<1 mph) indicate an inversion?’, ‘Does fog indicate an inversion?’, ‘Does dew indicate and inversion?’, ‘Do inversions form only after sunset?’, and lastly ‘If I do not have an inversion over my field, does my neighbor?’