Selective herbicides: Precisely kill specific weeds (such as dicotyledonous or monocotyledonous plants) without harming crops. For example, 2,4-D (concentration 0.5-2.5 kg/ha) is suitable for controlling broadleaf weeds in wheat fields, with a conversion rate of up to 90%.
Non-selective herbicides: Such as glyphosate (41% active ingredient, 200 mg/kg adsorption capacity), indiscriminately kill all plants, suitable for non-agricultural settings such as railways and industrial areas, but environmental isolation is required.
Contact herbicides: Such as paraquat (action time 24-48 hours), act only on the contact site, suitable for quickly killing annual weed seedlings, but with limited effectiveness against deep-rooted weeds.
In addition, biological herbicides (such as collodion spore suspension) and physical weeding techniques (coverage ≥95%) are becoming new environmentally friendly options. Their use requires comprehensive evaluation based on weed type, crop tolerance, and environmental safety (such as soil pH 6-8 compatibility).
