Zinc is one of the most essential micronutrients because of its ability to act as a catalyst for over 300 enzymes within a plant and its crucial role in seedling development. The most noticeable responses to early season application of zinc are usually seen in corn, sorghum and millet (C4 crops). I have noticed enhanced early season plant health and vigor, especially when applied in cool, wet soils. Additionally, increased crop responses are typically seen in soils with pH levels over 6.5 because zinc availability decreases as pH rises. Zinc can be applied several different ways:
- Broadcasted with dry fertilizer
- Foliar fertilizer applications
- In-furrow at planting
For today, I am focusing on In-furrow applications because this allows for the nutrient to be in the seed furrow, ready to be taken up by the root. It is also good to note that early season applications have been shown to increase early season growth and development of corn. However, these applications should have a stable chelator to combat any compatibility issues when mixed with other starter fertilizers. I often recommend Innvictis’ CAPTIVATE EDTA because it contains chelated zinc, along with NPK and sulfur (and is also a phenomenal starter fertilizer). However, if you know more zinc is needed due to field conditions, an extra 1-2 qts of Innvictis’ Zinc 9% EDTA can be easily added. If you are looking at other products, please ask the provider what chelator is used in that product. If the product contains a citric acid form of chelation, and you plan to mix in other products, tie-up issues are imminent and will lead to the creation of sediment build-up.
In-season Symptoms
In corn, a zinc deficiency is first noticed by a light yellow/white colored band starting to form on either side of the leaf midrib of the youngest leaf. As the deficiency progresses, the band can expandto the length of the leaf.
Zinc Deficient Corn By Alandmanson - Own work, CC BY-SA 4.0
Soybean zinc deficiency symptoms include interveinal chlorosis and in some cases, leaf mottling. Zinc deficiency symptoms in soybeans are similar to iron chlorosis. Depending upon geography, soil nutrient levels, and field history, the correct conclusion can be made for the symptom. However, pulling tissue samples of the affected plants provides the exact nutrient deficiency. Soil sampling provides another form of monitoring zinc levels in your soil profile. Talk to your crop advisor or send me an email and together we can formulate a plan of attack to give your crop the best shot for 2020.
