Background

Scientific research shows that humic and fulvic acids are biostimulants—enhancing nutrient availability and uptake, improving plant root growth and mass, and impacting both crop yield and quality.

Objective

The focus of this study was to assess the effect of pre-plant application of a raw humic product on potato yield.

Materials & Methods

One week before planting the Russet potatoes, 150 lb/acre of Huma® OM 1-3 mm organic granular humate was applied on May 17 to test plots at the research facility of SGS in Aurora, S.D. All the plots received a grower standard (GS) fertilizer program based on the region’s normal practices. Nitrogen was from urea, phosphorus was from mono-ammonium phosphate (MAP), and potassium was from potash. The GS included 150 lbs. of N and 15 lbs. of P and K each. The trial was conducted as a randomized complete block with four replications. The potatoes were planted on May 24 and harvested on September 1.

Results

The pre-plant treatment of soil with Huma® OM 1-3 mm organic granular humate improved the potato yield high enough to give a 9% advantage (Figure 1); however, results were not statistically significant. In addition, the plants in Huma® OM 1-3 mm organic granular humate treated plots contained slightly (not statistically significant) higher levels of N, P, K, Mg, and as well as Brix (Table 1).

Table 1. Comparison of leaf sap Brix and nutrients between plants in soil treated with and without humate material

Table 1. Comparison of leaf sap Brix and nutrients between plants in soil treated with and without humate material

Figure 1. Potato Yields Compared With Grower Standard vs. Grower Standard + Huma® OM 1 3 mm Organic Granular Humates

Figure 1. Potato Yields Compared With Grower Standard vs. Grower Standard + Huma® OM 1 3 mm Organic Granular Humates

Conclusions

The potato yield improvement due to the pre-plant application of Huma® OM 1-3 mm organic granular humate plus GS translated into a higher net gain of over $100 per acre when compared with the GS program alone. The net gain gave a return on investment (ROI) of 5 to 1. Our results confirmed the findings of others that adding humic substances to soil can give a yield bump to crops. It is well known that humic substances stimulate plants to uptake more nutrients and have more efficient photosynthesis. In this experiment, we see some evidence of that because humate-treated plants had slightly higher Brix, N, P, K, and Mg.