Most gardeners recognize the importance of the macronutrients: nitrogen (N), phosphorus (P), and potassium (K) since it’s labeled on most fertilizer packages. These three nutrients are consumed in the most considerable quantities. But, they’re not the only ones the plants need for their growth. Plants need other nutrients as well, like zinc!
A balanced diet for us means a combination of several nutrients in their proper concentrations. Similar is the case with plants. There are 16 different nutrients that a balanced plant diet must include, zinc (Zn) being an important one.
But why do plants need zinc? What problems can result if the soil lacks zinc? How can you counter zinc deficiency in plants? Continue reading this post, and you’ll find out all about its role in a plant’s diet.
Zinc – A Critical Micronutrient
The 16 plant nutrients are divided into three categories, primary, secondary, and micronutrients. These classes are not based on the importance of these nutrients to the plant’s health, all of them being equally important. Instead, they are based on the plant’s needed quantities, micronutrients being needed in only tiny amounts than primary and secondary nutrients.
Zinc is among the seven micronutrients needed by plants. Unfortunately, the amount of this element present in the soil is often so small that it’s easy to neglect it. But, without its presence, crops will fail to thrive.
Although it’s needed only in small amounts, zinc plays a vital role in plant development and is involved in several crucial processes for plant survival. So, ensure the soil has all the nutrients, including zinc, in their proper quantities for the plants to thrive!
Why Do Plants Need Zinc?
Before discussing the deficiency symptoms and treatment options, let’s start by answering the question that brought you to this page – why do plants need zinc?
Zinc occurs in plants in various forms. It can exist as a free ion, as a part of proteins or other macromolecules, or as a complex one with certain low molecular weight compounds.
Zn is critical to plants’ development; it takes part in many essential processes, whichever form it may exist in. Here are some of the uses of zinc in a plant:
- It helps plants produce chlorophyll.
- It allows plants to convert starch to sugar.
- Zinc is also involved in the formation of some carbohydrates.
- It activates enzymes that are responsible for the synthesis of specific proteins.
- Its presence in plant tissues makes it possible for plants to tolerate cold climates.
- It takes part in the production of auxins, which control growth and internode elongation.
So now you have the answer to ‘why plants need Zn?’. With so many zinc functions in plants, one thing is for sure! Plants need a consistent supply of zinc to ensure optimal development and the most significant yield.
What Are Normal Zinc Levels In Soils?
The concentration of zinc varies in different types of soils. For example, sandy soils and histosols typically have lower zinc concentrations than others. The optimal range of zinc concentrations should ideally be between 0.10-2.0 ppm in any growing medium. The average zinc concentrations in plant tissues range between 15 to 60 ppm. To understand more about this thing called ppm, read this article.
Deficiency or toxicity may result if zinc levels in the soil or plant tissues lie way beyond this range. These problems can impact the growth and yield of crops if not addressed promptly. Keep an eye out for the symptoms, and once you’re sure what the problem is, correct it before it damages your plants irreversibly.
Zinc Deficiency In Plants
Without adequate zinc levels in the soil or plant tissues, you’ll notice many problems. In addition, the lack of this critical micronutrient will affect several processes in plants. Therefore, it’s essential to know the reasons for the deficiency, its symptoms, and solutions to save your plants from permanent damage.
Different Reasons For Zinc Deficiency In Plants?
Zinc deficiency doesn’t always occur due to low zinc concentrations in the soil, although it’s one reason. There may be other reasons too. Here are some important ones:
- Some plants are more susceptible to zinc deficiency.
- Low zinc concentrations in the growing medium can cause zinc deficiency.
- An excess of other nutrients, like iron, calcium, or copper, can lower zinc absorption by plant roots.
- Soil with pH levels close to or greater than seven will have low zinc solubility, inhibiting plants’ zinc uptake.
- High organic matter content encourages zinc complexes with organic matter, making it less available to plants. Although organic matter improves soil structure and nutrient concentrations in the long run, don’t hold back on these amendments.
Different Symptoms For Zinc Deficiencies In Plants
Zinc is immobile, as is the case with most micronutrients. As a result, the deficiency symptoms will appear on the new growth. Symptoms will vary with the species. But, some common signs you’ll notice include:
- Stunted growth.
- Distorted leaves.
- Brown spots on new leaves.
- Leaves will be smaller in size.
- Chlorosis or yellowing of the leaves. In some species, young leaves are affected, while in others, both old and new growth can show yellowing. The leaves’ base, near the stem, typically turn yellow as a result of zinc deficiency.
How To Identify Zinc Deficiency In Plants?
Symptoms of zinc deficiency are like those of other micronutrient deficiencies, so it’s easy to confuse them. Don’t apply any supplemental zinc to the soil unless you’re sure that it’s a deficiency that your plants are experiencing. The only way to be sure is to perform tests on the soil and plant tissues.
With these tests, you’ll know whether it is, in fact, zinc deficiency or a different condition that’s causing the symptoms. You’ll also know if the soil lacks the element or if some other reason is causing zinc deficiency.
How To Prevent Zinc Deficiency In Plants?
Most water-soluble fertilizers contain adequate amounts of zinc in them to prevent deficiencies. So if you’re fertilizing crops regularly and there’s a consistent supply of organic matter to the soil, zinc deficiency won’t appear in the first place.
Sandy soils are more susceptible to nutrient deficiencies. Frequent compost and organic matter applications improve the soil structure over time, helping it manage nutrients and ensure a balanced supply to the roots.
Restricted root growth due to heavy soil can also cause zinc deficiency. Aerating the soil and adding organic amendments can help improve the structure of heavy clay soil.
How To Correct Zinc Deficiency In Plants?
For a quick fix, foliar spray with kelp extract or other micro-nutrient fertilizers containing zinc can help. Gardeners commonly use foliar sprays to correct zinc deficiencies in fruit trees and grapevines.
If the deficiency symptoms are visible, foliar sprays are faster to resolve the problem than soil applications since it provides zinc to the plants exactly where they are needed. This helps counter the deficiency in its initial stages and helps revive the plant. But remember that this isn’t a permanent solution.
Soil amendments will be needed to maintain the correct nutrient balance for the plants to thrive. Avoid using high-phosphorus fertilizers as they can lower Zn availability for plants.
Growers also add zinc sulfate, chelated zinc, or zinc ammonium to raise zinc levels in the soil. But, balanced micronutrient fertilizers are suitable for treating soil low in zinc since they prevent nutrient imbalance.
How Does It Affect Us?
Zinc deficiency in plants also affects us! Other than obstructing plant growth and yield, it also means our diet lacks it. It’s an essential nutrient for human health, responsible for building a healthy immune system, thyroid function, blood clotting, healing, etc.
Zinc deficiency in humans can cause hair loss, growth retardation, acne, loss of appetite, and even nerve damage. So it’s essential to make sure plants maintain the right supplies of nutrients and bring a balanced diet to our plate.
Zinc Toxicity In Plants
Yes, zinc toxicity also exists! Although rare, sometimes plants may be taking more of this micronutrient than they need. For example, acidic soil or high magnesium levels can make the plants susceptible to zinc toxicity. As a result, chlorosis and stunted growth may be seen in the affected plants since excess zinc competes with other nutrients’ availability.
Symptoms of phosphorus deficiencies, iron, copper, or other nutrients may be visible in such plants. Test the soil for its pH levels and nutrient concentrations before making suitable amendments.
By now, you’ll have understood why plants need zinc and why it’s essential to make sure plants are absorbing the proper concentrations of this micronutrient through their root system.
Build a healthy organic soil rich in all the essential plant nutrients and make them readily available to the roots. Then, if you still notice zinc deficiency symptoms, diagnose the problem and correct it before taking a toll on your crops.
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