Chromatic validation of herbicides used in vegetable production

Authors: GREY, TIMOTHY - University Of Georgia; Porter, Kayla

Submitted to: IntechOpen
Publication Type: Book / Chapter
Publication Acceptance Date: 10/2/2023
Publication Date: 10/31/2023
Citation: Grey, T.L., Porter, K.M. 2023. Chromatic validation of herbicides used in vegetable production. IntechOpen. na. https://doi.org/10.5772/intechopen.1003229.
DOI: https://doi.org/10.5772/intechopen.1003229

Interpretive Summary: Many vegetables are produced using a plasticulture system, which generally consists of raised beds of soil covered with plastic mulch. Herbicides are applied to the soil once beds are made but before they are covered with mulch. These herbicides need to provide the longest residual weed control possible while still maintaining crop safety. Producers often utilize the same plastic mulch for two to five crop production cycles over the course of multiple growing seasons, allowing growers to spread the cost of production over multiple crops and mitigating the cost of reapplying mulches for each crop. The time between the termination of one crop and the planting of another allows for the germination, emergence, and establishment of troublesome weeds in old plant holes. Often, one of the greatest challenges in plastic mulch vegetable systems is eliminating the first crop and any weeds growing under and through holes in the mulch prior to planting the subsequent crop. Herbicides that can be applied over-the-top of plastic mulch prior to transplanting a crop without damage are crucial for maintaining vegetable weed management systems. Herbicide use in vegetable production can raise concerns if information is not known about carryover effects or how the individual herbicide will behave in soil or on the surface of the mulch bed. This can be mitigated by quantifying herbicide dissipation in various vegetable production scenarios by utilizing field and analytical techniques, such as chromatographic systems. Coupling chromatographic outputs with environmental data, such as rainfall and cumulative solar radiation, we can predict half-life information and dissipation rates for individual herbicides. Growers can directly use this information when making crucial weed management decisions.

Technical Abstract: Herbicides are necessary for successful vegetable production in the Southeastern United States. Along with bare-ground production, low density polyethylene (LDPE) mulches are often utilized to produce multiple crops (2-4) by rotation over the course of a 12-to-24-month period. These include fresh market tomato, pepper, cucurbits, eggplant, and cabbage. For LDPE mulch vegetable production, between each crop growers must apply contact and residual herbicides to mitigate weeds. However, these herbicides can remain on the mulch and injury transplants. Herbicides are often soil applied for bare soil production as well as under the LDPE mulch. Herbicide carryover in soil using these vegetable production methods can also result in management issues. Proper quantification analyzing the dissipation is critical in the decision-making process for growers to prevent unnecessary crop losses. A series of experiments have been conducted to quantify the dissipation of the herbicides flumioxazin, fomesafen, glufosinate, glyphosate, halosulfuron-methyl, paraquat, S-metolachlor, and sulfentrazone over time using UPLC/MS and bioassay methods. These methods are presented.