ИСТИНА

Despite huge amount of publications on the beneficial effects of humic substances on crop growth and productivity over more than six decades, the use of humates, which are humic-containing commercial products, in agriculture varies and there is skepticism about their effectiveness. In light of the potential benefits of humates, together with their inconsistent performance under field conditions, we sought to improve the understanding of the effects of humates on crop yield under open-field conditions by conducting a systematic review and a meta-analysis of the published literature. More specifically, our objectives were (i) to quantify the magnitude of plant-growth promotion resulting from humates application, in terms of yield; (ii) to determine the influence crop type, enrichment of humates with macro- or microelements, soil properties, and the manner of application on plant-growth response to humates. To reach these goals, ISI Web of Science and eLIBRARY databases search for the period of 1992-2022 has been conducted. A combination of searched terms included “humic” AND “field” AND “yield” or Russian-language equivalents. From a total of 407 papers originally found, 123 were retained for the review and meta-analysis, which provided over 687 data points on which to base the performed analysis.