Application of a Formulated Humic Product Can Increase Soybean Yield
Application of humic products to crops remains controversial. We conducted a field study in Iowa over four environments from 2012 to 2014 examining productivity of soybean [Glycine max (L.) Merr.] receiving foliar application of a humic product at one of four application times based on plant development. Humic product application never influenced soybean height at harvest. Soybean yield increased following application of the humic product in two of four environments, but application timing was not completely consistent between these two environments. In one 2012 environment, humic product application at V2, V6, and R2 resulted in greater yield than the untreated control. In the other 2012 environment, application of the humic product at V2 resulted in improved yield over the untreated control. Application of the humic product never influenced seed oil concentration; however, seed protein concentration was decreased following application of humic product at V2 and R2 in a single 2012 environment. Use of the formulated product influenced returns from –$81 acre−1 to +$171 acre−1, depending on the environment. The environments where humic product application positively influenced yield and seed quality had greater rainfall deficits and air temperatures above the long-term average.
This article is published as Lenssen, Andrew W., Dan C. Olk, and Dana L. Dinnes. "Application of a Formulated Humic Product Can Increase Soybean Yield." Crop, Forage & Turfgrass Management 5, no. 1 (2019): 180053. doi: 10.2134/cftm2018.07.0053.