The current marketing of humic acid products to potato growers indicates that incorporating these materials at planting will lead to improved nutrient uptake, increased soil health, vigorous growth, and increase in yields. Humic acids are composed of long chained, organic molecules that can be naturally or industrially made. In 2024, the in-furrow application of humic acid was evaluated in Pennsylvania on the cultivar ‘Lehigh’. Plots were evaluated for nutrient uptake and photosynthetic capacity as impacted by use of Black Label Zn, Duo Maxx, Fertiactyl, Humi-Flex FA, Hydra-Hume, and Monty's Carbon. Preliminary data show no statistically significant difference between applied products and an untreated control for macro and micronutrients analyzed by plant tissue sampling. No statistically significant differences were observed for stomatal conductance, chlorophyll fluorescence, or electron transport rate. These preliminary data suggest that there is no positive return on investment with using humic acid products in-furrow at the time of planting. As part of a three-year study, data from 2023 supported a similar conclusion.
