1. Fulvic acid is a specific sorbents of pesticides
Pesticide sorption and desorption in soil is a crucial factor that corresponds to the effects of pesticides to the environment. Since without proper sorption and desorption mechanism of pesticide in soil, problems such as decrease in microbial activities and increase in pesticide’s chemical degradation, volatilization or leaching might occur. Therefore, Fulvic acid, an organic molecular chain with phenolic and carboxylic functional groups is used as a sorption-desorption agent to counteract these problems. Fulvic acid works well with various polar or ionic pesticides. For example, the phenolic groups of Fulvic acid can result strong hydrogen bonding with the nitrogen of the imidacloprid molecule. Apart from Imidacloprid, Fulvic acid can also form strong sorption mechanism with carbamates (carbaryl and carbofuran), phenoxyacetic acids (2,4-dichlorophenoxyacetic acid (2,4-D) and 4-chloro-2-methylphenoxyacetic acid (MCPA)), and aniline derivatives (metolachlor).
2. Fulvic acidas tank mix buffering agent
As mentioned above Fulvic acid effectively form sorption mechanism with specific pesticides through hydrogen bonding, ionic, and charge-transfer processes. Thus, when Fulvic acid is applied together with pesticides in tank mix, it would act as a buffering agent which protect the pesticide molecules from various metals/salts in irrigation water. Improving the solubility of pesticides while also acting as an effective carrier of pesticides to plant cells. Ultimately, it has been studied that using Fulvic acid together with polar or ionic type pesticides can reduce the usage of respective pesticide around 20-30%.
3. Fulvic acid as pollutant absorber
Moreover, when Fulvic acid is applied whether before or together with pesticides, it would act as a pollutant absorber when the pesticide droplets fall into the soil after spraying. Consequently, reducing the toxicity of pesticides to microbials in the soil and the sprayed crops as well. Fulvic acid also has the function of degrading residual pesticides under certain conditions.
Reference:
(1) Ćwieląg-Piasecka, Irmina, et al. “Humic Acid and Biochar as Specific Sorbents of Pesticides.” Journal of Soils and Sediments, Springer Berlin Heidelberg, 26 Mar. 2018, https://link.springer.com/article/10.1007/s11368-018-1976-5.
(2) Alister, C., et al. “Humic Substances and Their Relation to Pesticide Sorption in Eight Volcanic Soils.” Planta Daninha, Sociedade Brasileira Da Ciência Das Plantas Daninhas, 17 Apr. 2020, https://www.scielo.br/j/pd/a/T8L5pjfwGKvsnkRj3GNTNtk/?lang=en#.
