Although herbigation (application of herbicides by irrigation) has increased in Brazil, the research results evaluating this technique are scarce and mostly unknown, especially when herbigation involves the use of postemergence (POST) herbicides. The objective of this review was to discuss the main articles related to POST herbicides applied through overhead sprinkler irrigation In most of the studies revised a simulated sprinkler system was used and the herbicide rates applied through herbigation were the same used through conventional application (spraying). The amount of water used to apply a given herbicide varied from 1 to 14 mm (10,000 to 140,000 L ha¹). The most studied herbicides which were effective when applied through herbigation are: bromoxynil, acifluorfen, fomesafen, lactofen and the aryloxyphenoxypropionate herbicides. The herbicides atrazine, chlorsulfuron, dicamba, sethoxydim, and triasulfuron, included in, at least, one study, showed potential for weed control through herbigation. These herbicides have, at least, two of the following properties: low water solubility, quick leaf absorption, and root absorption. Variation in the volume of water for herbigation had little or no effect on herbicide weed control effectiveness. In general, mixing a non-emulsified oil with the herbicide before the injection into irrigation water may increase deposition and retention of herbicides on the leaf surface. Other factors that can affect herbicide effectiveness applied via herbigation are water quality and application timing. Generally, the following herbicides are not weed control effective in herbigation: bentazon, glyphosate, and paraquat, since they have high solubility in water, being slowly absorbed by foliage and/or not absorbed by the roots.
chemigation; herbigation; amount of water; non-emulsified oil
