Calcium Products - Andrew Hoiberg, Ph.D.
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Andrew Hoiberg, Ph.D.

Andrew Hoiberg, Ph.D.

Update from Iowa Soybean Association On-Farm Network on Sulfur

A few weeks ago, we had the pleasure of attending the Iowa Soybean Association’s On-Farm Network (OFN) conference in Ames. One of the highlights of the conference for me was the presentation by Dr. Tracy Blackmer about sulfur.

Sulfur application over the past 30 years was generally considered non-essential due to the high levels found in our atmosphere from power plant emissions high in sulfur, thereby satisfying plant needs. Times and emission standards have changed and, as a result, sulfur levels are much lower in atmosphere and soil than they were in 80s and 90s. Dr. Blackmer observed sulfur deficient corn in recent years and even dug out some old photos during his time at the University of Nebraska that showed sulfur deficiencies—at the time unnoticed, which was very surprising to him. Perhaps we have negated the benefits of sulfur application for far too long!

Gypsum (calcium sulfate) is a great source of sulfur and our gypsum product (SuperCal SO4) has been included in strip trials—on both corn and beans—within the OFN for the past few years. Some observations from aerial photography have shown strips that received gypsum are much darker green than those that didn’t. Looking further into the data, these same farms showed a corn yield increase from 0.5 to 8.8 bushel from sulfur application, as well as tissue testing that confirmed sulfur deficiency in the untreated strips. There is some thought that the sulfur being present in requisite amounts helps the plant use nitrogen more efficiently.

We look forward to further investigation of the benefits of sulfur application on corn in the upcoming season and beyond! Our thanks to all the cooperators within the OFN.


Increasing research efforts at Calcium Products

In autumn of 2012, Craig Dick and I began discussing a Calcium Products research agronomist and manager of research & development (R&D). I was thrilled at the idea and gladly accepted the position a few months ago.

I completed my Ph.D. at Iowa State University in May 2012 in horticulture, with a research specialization in turfgrass science. I know that may not equate into corn and soybean agronomy at first glance, but one of the purposes of obtaining a Ph.D. is to show you have learned how to subjectively think about problems and use the scientific method via research to answer them. Although my concentration was in the turf world, I have a well-rounded education that can be applied to any area of plant science. I started part-time with CPI in October while finishing my post-doc work at ISU and started full-time January 1. We have been busy exploring new avenues and expanding existing ones for research and development opportunities.

On-farm strip trials are one area we are exploring. CPI has been doing these for quite a few years, and the idea is to increase product awareness by putting it into the hands of the farmer through our Prove-It program. Sometimes the dialogue between scientist and farmer gets lost in translation; when a farmer talks to another farmer about what worked it's very effective. What better way to spread the message of soil health than through our customers? We put the power in your hands to realize how our products can help your bottom line. We are looking to involve as many farmers and co-ops as possible into our Prove-It program, as well as the Iowa Soybean Association's On-Farm Network, which has been a great cooperative venture we hope to expand in the future.

University research is another area we are starting to increase R&D efforts. CPI has been involved with this in the past, however, cooperating with universities is often a tedious process and can involve considerable cost depending on the intensity of the experiment. We have identified key areas in soil science that involve our products in need of up-to-date research and information. It is our goal to help drive the science to answer these questions and increase the available knowledge base in these areas.

We are also increasing our in-house research efforts. This is where the 'D' of R&D comes in; we are always aiming to improve the physical characteristics of our products to ultimately benefit the end user. We do not simply manufacture a product in the cheapest and easiest way and sell it. On the contrary, we put considerable time, research and money into producing the best product available so we can help growers improve their soils. Beyond the 'D,' we are also looking at small-scale trials with different coatings for our pellets to expand into different agricultural and horticultural markets. Further, we are conducting small-scale experiments on different crops with our existing products to determine what benefits we can offer growers beyond the corn/soybean and turf markets.

Finally, we are always interested in knowing what problems and/or questions growers have for us. Often, these interactions with growers are what spawn new product ideas and research. So, please do not hesitate to contact anyone in the company if you have an idea for a research project or need a question answered about how any of our products work!




More sulfur updates...

While reading the 2012 Annual Farm Progress Reports from Iowa State University's Northern Research Farm in Kanawha, IA, we discovered another trial investigating sulfur fertilization via gypsum on corn. The impetus for the study was the same as the Iowa Soybean Association's; sulfur deficiencies are becoming widespread in both corn and alfalfa in Iowa and many other midwestern states. The experiment was performed by Dr. John Sawyer and David Rueber of Iowa State University.

Four rates of sulfur (5, 10, 20, 40 lbs/A) were applied to two different soils—one with low organic matter and a slope, and one with higher OM and less slope—as was a non-treated control (no sulfur) to compare differences throughout 2011 and 2012. These rates were applied to corn in 2011 and soybeans in 2012. The 2011 plots were planted to corn after soybean in 2011 and planted to corn again in 2012 to test residual effects of sulfur application. In 2012, additional plots were planted to soybean from corn the previous year.

In June 2011, corn leaf greenness was visibly different among plots that had sulfur applied vs. those that did not, as well as having taller plants. By late June, there was still a height difference but the color differences were diminished. Despite visual differences, there was no difference in yield between the treated and non-treated pltos.

This is where it gets interesting...

In 2012, the plots that had received sulfur in 2011 showed no visible differences from those that did not, unlike the differences in 2011. However, when harvest time came, there was an increase in corn yield for sulfur treated plots as a whole when averaged and compared against the non-treated control plots. So, there's something happening with the sulfur in the soil from year to year that isn't being accounted for that has increased corn yield as a residual effect. This is similar to what we saw with the Iowa Soybean Association On-Farm Network trials over the last few years; residual activity from sulfur application making a yield difference a year after we thought it would.

Soybeans did not show any statistically different response to the sulfur application in 2012.

This study will continue in 2013 and we are excited to see the results.


Interaction of zinc and calcium

Zinc is an extremely important micronutrient that has many roles in plant health and deficiencies are widespread, even if unknown to the grower. Recommendations for zinc levels in soils are dependent on crop, soil type, pH and other nutrient status and can range depending on which institution is offering the recommendation. Generally speaking, below 1ppm on your soil test indicates that you should apply some type of zinc fertilizer. However, growers should pay attention to their soil tests and site-specific factors, because while 1ppm of zinc in one soil type may be sufficient, 4ppm in another soil with zinc antagonists may be a better target.

Deficiency symptoms are generally seen in new growth, early in the life cycle of the plant and result in stunted growth, shortened, sometimes split internodes and discoloration of new leaves—the color of which can vary depending on plant species. Internally, zinc deficiency can result in reduced water uptake, phytohormone (hormones that regulate plant growth) activity and uptake of other nutrients. In corn, zinc deficiency results in a broad band of bleached tissue on either side of the midrib, beginning at the base of the leaf and generally staying in the lower half of the leaf. Severe zinc deficiency may result in new leaves that are nearly white, a phenomenon called 'white bud.'

Zinc availability is very sensitive to pH, and is therefore reduced by over-liming or by other agents causing high pH. However, rates and acidifying forms of N commonly used in agriculture generally alter the pH enough in the rhizosphere to enhance zinc uptake. Zinc is also well known to interact with P; where zinc is deficient, P uptake is increased in certain plants and vice versa. Zinc deficiency is also more common on cool and wet soils with low organic matter.

Specifically, we are interested in the interaction of zinc and calcium, a topic on which there exists little information. Feedback from growers indicates that when zinc levels are not sufficient, they don't see a good response from our products containing calcium. Why this happens, we are not exactly sure, however, we theorize that perhaps the limiting factor is zinc, rather than the calcium, which results in no visible effects from the application. One thing we do know is that alkaline earth cations, specifically calcium, can inhibit zinc uptake. This may have something to do with the fact that a large amount of basic cations in soil generally result in higher pH values, which is known to inhibit zinc uptake. One way to combat this problem is to apply some slightly acidifying N fertilizer that will cause a temporary shift in pH—favorable to zinc uptake—in the rhizosphere to combat the inhibitory effects from calcium. The take-home message is that if calcium-based products are needed in your system, it is prudent to pay attention to your zinc levels and adjust with a zinc fertilizer, or another method to ensure your plants are getting the requisite amount of zinc.


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