Iron is an essential nutrient for plants, but too much of it in soil can be problematic. It can lead to root damage, stunt plant growth, and have a negative impact on crop yields.
Proper soil management, such as improving soil drainage, fertilizing judiciously, and paying attention to soil pH, can help reduce iron levels and promote healthy plant growth. Remember, healthy soil will result in healthy plants.
Read on to explore the root causes of high iron content in soil and the ways to reduce it. You might also enjoy reading: Best and Effective Ways to Identify Iron Deficiency Symptoms in Plants.
1- Soil pH
pH indicates the acidity or alkalinity of soil, ranging from 0 to 14, with seven being neutral. A pH level below 7 means the soil is acidic, while pH levels above 7 indicate alkaline soil (Source: Utah State University)
Soil pH plays a critical role in determining the amount of iron present in the soil. The higher the pH level, the more iron is available in the soil. Typically, as the pH level increases, the soil becomes more alkaline, making the iron more soluble and available for uptake by plants.
High levels of iron in alkaline soil can also lead to the toxic accumulation of other nutrients, such as manganese and aluminum, making it difficult for plants to thrive.
2- Poor Soil Drainage
Poor soil drainage can also affect levels of iron in the soil. According to Utah State University, poor drainage subjects plant to an always wet root system, resulting in iron deficiency, increased root disease, and other growth problems.
In some cases, when waterlogged soil remains wet for an extended period, the lack of oxygen creates anaerobic conditions, which encourage the growth of bacteria, which might convert the iron present in soil into a soluble and plant-available form.
Over time, the accumulation of excess iron can lead to root rot, a bacterial disease that affects the root system and causes plant death. Additionally, insufficient drainage can trap water and cause salts, including soluble iron, to concentrate in the soil.
3- Overfertilization
While iron is essential for healthy plant growth, overusing iron-fortified fertilizers can lead to an accumulation of excess iron in soil. Furthermore, chemical fertilizers like ammonium sulfate and ammonium nitrate can increase soil acidity, leading to an increase in iron uptake by plants.
And, of all the major fertilizer nutrients, generally, nitrogen is the main nutrient that affects. Nitrate-based fertilizers are the least acidifying of nitrogen fertilizers, while ammonium-based fertilizers have the greatest potential to acidify soil (Source: Adelaide University)
I recommend you use fertilizers sparingly and only apply enough to meet plant nutrient needs because overuse of fertilizers can introduce excessive minerals and salts into the soil, leading to an increase in iron content.
4- Weather Conditions
Heavy rainfall, flooding, and increased humidity can all contribute to high levels of iron in soil. When water and humidity are high, the iron present in the soil becomes more soluble, resulting in an increase in soluble iron levels in soil.
Moreover, heavy rain can even lead to the erosion of soil, further increasing the soluble iron content of soil. Also, waterlogging limits oxygen availability, leading to anaerobic conditions that cause iron reduction, which increases the concentration of iron in the soil.
5- The Type of Soil
Certain soil types, such as clay soils and red soils, have a naturally higher level of iron than other soil types. In these cases, iron can be beneficial, but when it is present in excess, it can cause plant growth problems.
6- Soil Composition
Soil is generally composed of minerals such as iron, copper, and zinc; however, when the level of these minerals exceeds the recommended threshold, it can lead to high levels of toxicity.
High iron content might typically result from the presence of other minerals in the soil, like manganese, aluminum, and magnesium, which cause soil acidity levels to increase, occasioning iron accumulation.
I encourage you to test your soil to help you identify the root cause of the iron problem. You can invest in a Soil testing kit available on Amazon.
7- Soil Erosion
Soil erosion usually occurs due to natural disasters like floods or landslides, leaving the topsoil bare and exposed.
In some cases, soil erosion exposes soil rich in iron, which can increase the iron concentration in the soil. In addition, soil erosion introduces an excess of minerals and salts into the soil, which contributes to the increased iron in the soil.
8- Poor Soil Management
Poor soil management practices also contribute to high iron levels in soil. For example, not practicing rotation crops, excessive tillage, and overgrazing can compact the soil, slow water movement, and limit soil nutrients.
Furthermore, growing the same crop for multiple years on the same land without soil amendments can lead to a build-up of iron, imbalance soil pH levels, and increase soil acidity.
What to read next:
- Best Ways To Deal With Too Much Iron In Your Garden’s Soil.
- How to Successfully Reduce Iron in Soil: For Healthier Plants and Better Harvests.
- How to Effectively Identify Iron Deficiency Symptoms in Plants.
Wrapping Up
High levels of iron in soil can be detrimental to plant growth, leading to nutrient deficiency, stunted growth, and chlorosis. Excess iron in the soil occurs due to poor soil management, environmental factors, overuse of chemical fertilizer, soil erosion, and soil composition.
Soil testing can help you identify the root cause of the problem and help determine the most effective way to proceed.
With proper soil management, I believe it is possible to correct the problem of high iron in soil and optimize plant growth.
