Corn yields today are skyrocketing. In the next decade, Americans will be producing 17 billion bushels of corn each year, compared to 12.4 billion produced in 2011. Making sound soil management decisions will be increasingly important to boosting corn yields to produce the food the world needs.
Continued advancements in corn genetics and the next generation of insect-control traits have farmers looking closely at their fertility plans for 2013 to ensure the soil has what it needs to help hybrids succeed. When used in combination with sound soil management practices, adding a rootworm-resistant trait can make a big difference by reducing input costs and protecting the quality of the crop, and that means the soil has to be charged up for the plants of the future.
While increasing nutrients to meet the plants’ fertility needs is imperative, creating a sound balanced crop nutrition plan is the best way to ensure success.
New research conducted at the University of Illinois suggests that higher yields aren’t the only new thing farmers will see when they use advanced seed technology. Micromanaging the crop’s nutritional needs is critical in pushing the yield barrier and maximizing return on investment.
Roots Make the Difference
Roots are the primary route for nutrients to enter the plant. For the plant to take up soil nutrients, they must reach the roots by either interception (in which the root physically contacts the nutrient), mass flow (in which nutrients dissolved in water move toward the plant as it takes up water) or diffusion (in which nutrients move from areas where they are in high concentration in the soil to areas where there is a lower nutrient concentration in the root).
Nutrients that require root interception to be taken up by the plant are more sensitive to changes in root system health and size than those nutrients that are taken up by mass flow. Hybrids with Bt traits for corn rootworm resistance develop more intact, healthier roots and greater root mass than their nonresistant counterparts, suggesting an improved ability to access nutrients.
Nutrients by the Numbers
University of Illinois researcher Dr. Fred Below compared corn rootworm– (CRW) resistant hybrids with their conventional counterparts to examine the variance in nutrient uptake. Dr. Below examined six different hybrid pairs (each with the same genetics with and without corn rootworm protection) at two locations over the course of two years.
The benefits for farmers who utilize CRW-resistant traits were demonstrated in this research. As anticipated, the study results indicated that corn rootworm–protected hybrids provided 9 percent more biomass compared to those without insect protection, and yielded on average 10 percent more than their conventional counterparts.
As expected, hybrids designed to resist corn rootworm remove more nutrients to perform at their top levels. However, not all nutrients are affected equally. Nutrients such as phosphorus, potassium and zinc are relatively immobile in the soil, leaving nutrient uptake to rely on diffusion and root interception. Nitrogen and sulfur, however, are very mobile in the soil, so nutrient uptake mostly depends on mass flow.
In the past, farmers have often assumed that an acre of corn requires the same nutrients regardless of the variety they plant. The results of this study indicate that corn rootworm–protected hybrids have significantly different nutrient uptake than non-protected hybrids.
Table. Corn plant macronutrient and micronutrient uptake with and without corn rootworm protection at 240 lbs/ac⁻¹ nitrogen fertilization
*Increase in S was not statistically significant.
Source: Bender, Ross. 2012. Nutrient Uptake and Partitioning in High-Yielding Corn.
University of Illinois, Urbana-Champaign, Illinois.
Evaluating results of quantitative studies of increases in yield and nutrient removal from this study is complex, and the effects are likely the result of a number of factors.
Nonetheless, in order to achieve the full 10 percent yield increase possible by top seed technology, balanced fertility and accessibility of all key nutrients are essential.
While the greatest yields are realized when nitrogen is readily available, research from Dr. Below and the University of Illinois shows that unequal nutrient uptake by rootworm-resistant hybrids proves the significance of reevaluating fertility plans due to nutrient variation in order to maximize the high yield potential.
Nutrient Absorption Issues
Dr. Below also found that once the plant absorbs the nutrients, each nutrient plays various roles that are naturally required in higher concentration in some types of tissues. For example, phosphorus plays a critical role in energy storage and transfer, and is essential to seeds in order to grow new plants. As a result, almost 80 percent of phosphorus taken up ends up in the plant’s seed.
Zinc, critical for seed formation, is fundamental to develop pollen grains. Conversely, while still important to certain functions in seeds, nitrogen is required in larger quantities during the plant’s vegetative phases for its role in photosynthesis.
These differences parallel the varying nutrient uptake that occurs with the corn rootworm–protected hybrids compared to their conventional counterparts, indicating the need for a higher concentration of potassium, phosphorus and zinc in the seed, than other nutrients such as nitrogen and sulfur, when maximizing yields. The increase in required nutrients is a function of the higher yields achieved with a high yield system that included CRM-resistant hybrids and proper integrated pest management (IPM).
Nutrient applications should not only be increased to support higher yields, but must also be modified to address the unique increases in requirements for certain nutrients, especially phosphorus, potassium and zinc. As farmers continue to push the yield barrier, having a solid fertilizer plan in place to supply the crop with the nutrients it needs to reach its potential is critical.
The Next Generation of Fertilizer
Peak crop nutrition agronomic management practices are aimed at matching plant nutrient needs with nutrients from soil and fertilizer to optimize yield and get the greatest return on these genetics.
Regardless of whether a farmer is utilizing insect-resistant hybrids or their conventional counterparts, creating a sound crop fertility program is essential in achieving high yields. When choosing a product to help supply phosphorus and zinc to the crop, thus establishing a balanced soil fertility profile, distribution and availability of micronutrients are critical.
Products such as MicroEssentials® are designed to ensure balanced crop nutrition and establish the correct ratios of both macro- and micronutrients. MicroEssentials® SZ® combines a balanced formulation of nitrogen, phosphorus, sulfur and zinc into every granule.
The proprietary Fusion® technology driving MicroEssentials® ensures a uniform distribution of nutrients across the field that enhance plant uptake, allowing plants to use nutrients more efficiently, resulting in higher yields and profitability.
Advances in biotechnology, including insect-resistant hybrids, are a major key to pushing past the yield barrier. As new varieties offer solutions to and growers want to capitalize on seed investment, understanding fertility needs and maintaining balanced soil fertility are vital to maximizing yield and success. The Mosaic Company and the MicroEssentials® family of fertilizer products will continue to be instrumental in taking corn production to the next level.
Learn more at www.MicroEssentials.com.
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