Background

Humates are used as soil amendments that have shown to improve crop production. The usage of biochar as a soil amendment has gained traction and has also shown to increase crop yield.

Objectives

The aim of this study was to test how preplant soil application of organic (OMRI-Listed) humates (Huma® OM 1-3mm) and biochar separately and combined will affect soybean yield.

Materials & Methods

About two weeks prior to planting soybean seeds, the biochar (from pinewood) and Huma® OM 1-3mm were soil applied and incorporated to experimental plots at the Red River Research

Station, LSU AgCenter, Bossier City, Louisiana. The field experimental set up was a completely randomized design with four replications. Planting took place on May 15 and the crop was harvested on October 26. Table 1 describes the treatment application details. The Check treatment consisted of phosphorus fertilizer (P2O5 at 22.5 lb/acre) with triple super phosphate as the source (Table 1). Huma® OM 1-3mm and biochar were applied to plots that had already received 22.5 lb/acre of P2O5. (Table 1).

Table 1. Huma® OM 1-3mm and Biochar treatment description

Table 1. Huma® OM 1-3mm and Biochar treatment description

Results

The biochar and Huma® OM 1-3mm increased soybeans yield over the Check significantly (Figure 1). However, the yield differences between the biochar and Huma® OM 1-3mm were not statistically significant. The highest yield (83 bu/acre) resulted from combining Biochar with Huma® OM 1-3mm (Figure 1). The highest net income gain per acre ($253.99) and return on investment (4:1) were achieved by treating soil with Huma® OM 1-3mm.

Figure 1. Soybean yield under various treatments * Yield values with different letters are statistically different from others at 95% confidence level.

Figure 1. Soybean yield under various treatments
* Yield values with different letters are statistically different from others
at 95% confidence level.

Table 2. Comparison of yield values and economics between the Check versus other treatments.

Table 2. Comparison of yield values and economics between the
Check versus other treatments.

Conclusions

The soil amendments improved the yield of soybean crop. However, the cost effectiveness is quite visible with the Huma® OM 1-3mm (200 lb/acre) because it is applied at ten times less

per acre than the biochar (2000 lb/acre). In addition, it costs more and takes longer to apply 2,000 pounds of a material than 200 pounds per acre. The soybean yield advantage of biochar over Huma® OM 1-3mm treatment was only 4 bu/acre and still had a negative ROI.