A boost from boron

Aspire is a new fertilizer product from Mosaic with an analysis of 0-0-58-0.5. In simple terms, Aspire is muriate of potash with the addition of boron. The boron is homogeneously added before the product is prilled, making for more uniform distribution and less settling problems than standard fertilizer blends containing boron. Boron may get less attention than many plant nutrients because it is a micronutrient. It is required at much lower levels than nutrients like N,P and K. However, like all of the 17 essential nutrients for plant growth and development, without boron, plants won’t grow.

In the plant 90 percent of boron is found within the cell walls. Boron plays an important role in a cell wall’s ability to expand. A boron deficiency will exhibit itself via shortened and thickened cell walls. Boron is also in high demand during cell elongation of reproductive tissue during rapid growth. It is important that the plant have access to boron from soil reserves during reproductive stages because boron is not phloem mobile and is immobile in the plant. Dicot species such as alfalfa and cotton use higher rates of boron. You’ll more often see noticeable responses to boron fertilization in these crops.

In the soil, boron typically has either a neutral or negative charge making it prone to loss through soil leaching. Most available boron in the soil comes from mineralization of organic matter. Common areas where one will see boron deficiency are in coarse soils with low organic matter.

One of the greatest challenges of boron fertilization is the narrow window between deficiency of boron and toxicity. Even on crops like alfalfa it is not advisable to exceed 2 pounds of boron per acre to avoid boron toxicity. Even distribution of nutrients at rates below 2 pounds can be extremely difficult to achieve in typical blends. With the danger of toxicity from over fertilization and the challenges of even distribution of low rates of fertilizer, a homogeneously blended product like Aspire might have a distinct advantage.

2014 Aspire Trial Summary

As mentioned above, boron fertilization on deficient soil and on crops such as alfalfa and cotton is common. However, the benefits of added boron for crops like corn and soybean has been debated. To test Mosaic’s Aspire (0-0-58-0.5B) on corn and soybeans, MFA’s Crop-Trak consultants across western Missouri and southeast Kansas set up, monitored and collected harvest data from farmer trials. To test the effect of the boron in the Aspire versus the standard treatment of MOP (0-0-60), actual rates of potassium were kept equal across the two treatments. In most cases the majority of the field was treated with 0-0-60 as the K source and at least 20 acres of the field were treated with Aspire. To collect the data, consultants used weigh wagons to measure adjacent combine passes along the dividing line of the treatments, or the preferred method of the grower’s calibrated yield monitor. Use of yield maps allowed consultants to analyze results from both treatments in comparable areas of the field.

30 trials were conducted. Of those 30, we were able to successfully collect 20 data sets: 10 corn and 10 soybean (see tables 1 and 2).

On average Aspire showed a 5.33 bushel-per-acre advantage in corn with positive yield responses in 8 of the 10 trials. Those 8 trials also showed a return on investment over the breakeven point of 1.35 bushels per acre. The soybean trend was similar to the results in corn (see figure 3).

Soybean yield from the Aspire treatment yielded 2.85 bushels per acre better on average with 9 of 10 showing a positive response and 7 of 10 responding greater than the 0.5 bushels per acre breakeven (see figure 4).

After one year of large-strip testing, the initial results look very promising for Aspire as a method of boron fertilization. MFA plans to continue another year of testing Aspire in 2015. From the 2014 trials, we have already begun carrying the product at multiple locations for sale this crop year.