Zinc, one of eight micronutrients essential for plant growth, is one of the most common elements found in the earth’s crust. Unfortunately, it’s probably the most deficient micronutrient in crops worldwide. Most soils are either inadequate or possess nominal levels of zinc, which is why growers will find it in various nutrient packs.
The reason for this discrepancy is simple. Although zinc is available in the soil, air and water, it’s generally not available in a form that plants can utilize. Without adequate levels of zinc, plants suffer — and so do yields. This is because zinc is a critical component of various enzymes responsible for several metabolic reactions in crops, including the hormone that helps plants put their energy toward becoming taller and bushier. It promotes stronger root development and can help the plant withstand cold temperatures. Most critical of all is zinc’s role in the formation of carbohydrates, proteins, and chlorophyll.
Simply put, without zinc, we wouldn’t have chlorophyll, which gives plants their color by absorbing energy from the sun as they undergo the process of photosynthesis.
Understanding Zinc Deficiencies
Soil texture. Coarse, sandy soils and peat soils with low levels of organic matter are more likely to be deficient in zinc. Additionally, soils where the topsoil has been removed are more likely to lack zinc.
Soil temperature. In the cool months of early Spring, organic matter mineralization slows down, resulting in less zinc being available to plants.
High pH levels. As the soil pH increases, the availability of zinc drops.
High levels of phosphorus (P). Numerous studies have found an adverse relationship between phosphorus and zinc. For instance, excessive applications of phosphate fertilizers can cause zinc deficiency, lowering yields.
Because zinc plays such an essential role in plant development, signs of deficiency appear as early as two to three weeks, and symptoms may last throughout the growing season. In corn, zinc deficiency causes broad bands of striped tissue on the leaf closest to the stalk, and plants may appear stunted. In beans, zinc deficiency will appear as a yellowing of the lower leaves that turn bronze or brown over time. Symptoms will likely present in sporadic patches with uneven growth instead of covering an entire field.
Treating Zinc Deficiencies
In corn and beans, suspected deficiencies should be confirmed with plant tissue analysis and soil tests. If confirmed, fixing the problem takes several steps. First, work with your fertilizer dealer to use a water-soluble zinc fertilizer like zinc sulfate at 15-30 pounds per acre broadcast or two to four pounds applied in-furrow as starter. That will fix half the problem. Because, as noted earlier, many factors in the soil slow down the availability of zinc fertilizer to crops, the next step is to use Agnition Generate® in-furrow or as a foliar spray. Generate delivers zinc directly to microbes and the plant, bypassing the soil reactions that can tie up zinc.
Because we understand the importance of zinc, including its role in synthesizing important components of photosynthesis, you’ll find zinc included in our Generate, Commence®, and Procure® for corn products. Moreover, it’s provided in our patented Microbial Catalyst® technology that stimulates existing microbes by unlocking enzymes, making plants more efficient. This technology takes minerals such as zinc and delivers them in a completely soluble and available form for plants and microbes.