Metam (including metam-sodium and metam-potassium)

Metam (Metam) is a synthetic chemical agent utilized extensively in global agriculture, primarily available in the form of metam-sodium or metam-potassium. It acts as a broad-spectrum soil fumigant, serving as a critical tool for pre-planting sanitization of agricultural land and greenhouse substrates.

Chemically, metam is classified as a dithiocarbamate. When applied to soil, it undergoes a transformation process, breaking down into methyl isothiocyanate (MITC). This volatile compound spreads through the soil voids and aqueous phase, where it exerts toxic effects on a wide range of soil-borne pathogens, pests, and invasive plant seeds.

The primary use of metam is in intensive cropping systems, including nurseries, flower production, and high-value vegetable farming. It is highly effective in managing root-knot nematodes, soil-dwelling insects like wireworms, and numerous fungal pathogens such as Pythium, Phytophthora, and Rhizoctonia, which cause significant root damage.

• Requires well-prepared, moisture-balanced soil.
• Usually applied through shank injection or drip irrigation.
• Often necessitates soil sealing (tarping) to maximize gas retention.
• Requires a waiting period before seeding or transplanting to avoid phytotoxicity.

Safety is the most vital consideration when handling metam, as it is highly toxic and corrosive. Operators must adhere to strict personal protective equipment (PPE) protocols, including respiratory protection and protective suits. Because the gas can be hazardous to nearby plants and humans, strict buffer zones and aeration procedures must be followed strictly according to local agricultural regulations.