If you're ready to shoot fro even higher corn yields and are looking for avenues to add few more bushels, resist temptation to pour in 'moondust' products you know little about. Instead, take a look at secondary nutrients that could possible give your corn a boost, depending upon conditions.
One of those is zinc. Steve Butzen, Agronomy Information manger, recently explored zinc deficiency and how to fertilize for zinc in Corp Insights, a newsletter series from Pioneer. The first line of the summary says a mouthful: "Corn is more often deficient in zinc than in other micronutrients, and is responsive to zinc application when deficient."
Is that a blanket recommendation to hit every acre this spring with zinc? No. It's a suggestion to explore the possibility of whether or not adding zinc might help corn yields on your soils. According to Butzen, zinc deficiency tends to show up most on sandy or other low-organic matter soils, such as oils where topsoil has been removed, and on soils with high soil pH. Cool, wet weather favors deficiencies in seedlings if the micronutrient is borderline in the soil.
Of all the micronutrients, zinc is the most reliable when it comes to checking for it through a regular soil test, Butzen says. You can also follow results with plant sample analysis.
There are several sources of zinc if you believe it may be needed in one or more fields. Usually cost per unit of actual zinc, relative effectiveness of the product, and how it must be applied will all go into deciding which product to use.
Common fertilizers include zinc sulfate, which is 35% zinc, zinc-ammonia complex, at 10%, and which can be included in 10-34-0 style starter fertilizer, zinc oxide, at 70 to 80% but which must be finely ground, zinc oxysulates, which verify in composition of zinc, synthetic zinc chelates which run 9 to 14% and can be much more effective than inorganic sources, and organic residues, such as manures. Here, the content will vary, but manure is considered a very good source of zinc,.
You can learn more about possible zinc deficiencies and how zinc and pH interact in the 2011 edition of the Purdue University Corn & Soybean Field Guide, which is now available.