Application of Biostimulants and Herbicides as a Promising Co-Implementation: The Incorporation of a New Cultivation Practice

Over the last decades, biostimulants have been the center of discussion as a sustainable cultivation practice to promote plant growth and protect crops from abiotic stress. Agrochemical products are abundantly used for this purpose, which has resulted in raised international concern. Biostimulants, when used in combination with herbicides in some cases, could act as safeners, reducing the harmful and stressful effects of herbicides, and as a result, this combination can be considered a relatively new agricultural technique. However, they can also have adverse or non-significant effects, something that is strongly affected by the operating mechanisms of their components. In practice, there is a need to identify plant species-biostimulant-herbicide working systems from all the stakeholders of agricultural production. While research is still in its early stages, several studies have been conducted to evaluate various biostimulant and herbicide combinations to contribute to this goal. In this review, studies of their combination in sequential or mixed tank applications have been gathered to see how and if each specific combination can have a potential use in agricultural practice. The results indicated that there are various effects on crops, some of which were positive and others negative or non-significant. The fact that there is a countless number of possible plant species-biostimulant-herbicide combinations to be evaluated is a challenging task. Nevertheless, this review could serve as a foundation for the upcoming research. The aim of this review is to summarize the knowledge of some successful working examples of these three factors that could facilitate the incorporation of biostimulant and herbicide application, either sequentially or in a tank mixture, as a part of the agricultural practice for field crops.