Zinc Nutrition: How Important and How to Apply
Fertility is a complex topic within crop production. Soils and plants are two evolving, dynamic beasts. Everyone involved in the agriculture industry have been learning more and more about fertility and how far we can take it and, although a complex topic, the knowledge on the subject is improving year after year. When discussing a macronutrient like phosphorus or a micronutrient such as zinc we can start to sharpen our fertilizer practices and ultimately, figure out how to feed high yielding crops.
So what do we know about zinc in crop nutrition?
- Zn is an essential nutrient to all plants, and is required in grams.
- Crops like peas, canola and wheat have the highest probability of an economic response to zinc. In fact, peas are the highest users of Zn per bushel (how many grams? keep reading*...)
- Zn is integral in the formation of roots early on in the plant's life cycle. More roots give plants the ability to find more water and more nutrients.
- Zn plays a critical role in in hormone regulation and protein synthesis, having an effects in protein content, important for cereals like wheat and also for seed quality.
- Zn is also very important for grain formation and fill during flowering as it helps increase the number of kernels per spikelet or seeds per pod.
- Zn must be within millimetres of distance to the root for the root to be able to take it up.
- Over application of phosphorus and high soil test levels can decrease zinc availability and cause short term deficiencies.
As you can see zinc is very important and required throughout the entire plant's lifecycle. Getting the nutrition right from the start is critical. Understanding each crop’s physiological need is the first step to get the nutrition right. We can talk about Zn uptake much like we can talk about N or P uptake; only zinc will be in grams as opposed to pounds of nitrogen or phosphorus. So how much zinc are we talking about? A hard red spring wheat crop with a yield environment of 60 bu/ac will take up 208.8 grams throughout the growing season. A 50 bu/ac canola crop will take up 179 grams throughout the growing season. Another key point to consider about Zn is that it's immobile in the soil. This means that if you are going to incorporate zinc into your crop's fertility plan it must be placed in very close proximity to the seed. When using a granular zinc product, even at a very high rate of 2 lbs/ac, there aren't enough feeding sites for all of the plants to get enough of this nutrient.
Take an ice cream pail half-full of zinc sulfate fertilizer and try to spread that evenly over 1 acre. That is approximately what 2 lbs/ac would look like. Do you think there are enough feeding sites for all of the plants in 1 acre to get adequate zinc nutrition given the information mentioned earlier?
An approach that works to solve this conundrum is to utilize the dry blend of fertilizer already going down at seeding and coat it with micronutrients (zinc in this case). Each prill of fertilizer can be coated with zinc, which dramatically improves the distribution of the nutrient. More prills with Zn means more feeding sites for the roots to take up zinc, ultimately increasing yields. YaraVita PROCOTE is an oil based liquid technology that can be used to deliver micronutrients on your granular fertilizer blend.
If you would like more information about zinc or any other nutrient don’t hesitate to contact your local Yara agronomist.
