Scientific research shows humic and fulvic acids can have a biostimulant effect on plant root growth and mass, nutrient availability and uptake, and crop yield and quality.


The objective of this study was to compare and contrast the immediate effects that three types of humic products from Huma®, Inc. have on corn yield. Those products are:

  • Huma Pro® 16—a 16%* liquid humic/fulvic acid
  • OM 1–3 mm—an organic granular 70%* humic/fulvic acid
  • K Hume® OM—an organic granular 70%* humic/fulvic acid activated with potassium, making it highly soluble.

Materials & Methods

The plots were established at a farm in Boone, Iowa. The experiment design was a randomized complete block with three replications. The corn (Pioneer PO622Q: 34,000 seeds per acre) was planted in a field that had not had any humic/fulvic products applied before this study. The Huma® products were applied in spring immediately prior to planting. Each plot had 5 rows, each being 12.5 ft. wide and 200 ft. long. Water was provided by rain only.

The grower standard fertilizer (GS) included a total of 80 lb P/a and 120 lb K/a applied immediately before planting on June 2. The corn was then side-dressed with 150 lb N/a of 32% UAN on June 27. The 150, 80, 120 NPK fertilizer amounts were based on Iowa State University Extension Office recommendations for the region in a corn-soybean rotation. Table 1 describes the product application timing and method.

*Analysis of humic/fulvic acid using the Colorimetric Test Method


At harvest (October 22), all three of the humic/fulvic treatments brought about higher corn yields than did the control (Figure 1). Corn plants grown under K-Hume® OM (Treatment 3) produced higher statistically significant (P > 0.05 levels) yield results than those that only received the grower standard fertilizer program. The Huma® products resulted in a corn yield increase of 2%–9%, or 3–15 bu/acre (Table 2).


Applying and incorporating K Hume® OM to the soil before planting significantly benefited corn yield.

The liquid product (Huma Pro® 16), is easier to apply and is expected to have an immediate effect, but it has a lower concentration of humic/fulvic acid. The raw granular product (OM 1-3 mm) has a higher level of humic/fulvic acid than Huma Pro® 16, but its effect is expected to spread out over a longer time period (several crop seasons). The granular K Hume® OM product has both a higher level of humic/fulvic acid and is highly soluble, allowing it to have a greater immediate effect than the other humic products.