Why measure Iron and Aluminium in soil?

Role of Aluminium

Aluminum in the soil is especially known as a limiting factor on plant growth. Active Aluminium is in often cases toxic to plants and can disturb many functions such as plant nutrient, water uptake, and root hair elongation.

However, to some extent, Aluminium can also have beneficial effects on plant growth even though it is not considered an essential nutrient; in that case, the level of toxicity varies depending on the plant species. For certain crops, low concentrations of Al have shown a positive effect on growth, especially for crops adapted to acidic soils (e.g., Tea). With moderate Al levels, P availability can enhance H+, Fe, and Mn toxicity alleviated and genes associated with tolerance to abiotic stress-activated.

Generally, for most plants, a pH level between 5,5 to 6,5 is favorable, with a lower soil pH <5. Aluminum becomes soluble, and the risk of Aluminium toxicity is increasing.

Soil acidification is a common process in agriculture, often caused by inefficient soil management and irrigation or inefficient fertilizer application. Therefore, soil nutrients levels through analysis are vital to mitigate soil acidification and avoid possible nutrient toxicity.

Role of Iron

In contrast to Aluminium, Iron is an essential micronutrient that plays a significant role in plant metabolic processes such as respiration, photosynthesis, and DNA synthesis. An imbalance of Iron in the soil can cause iron chlorosis in the plant, while excess amounts of Iron result in toxic effects, which both can result in yield loss.

Most well-aerated soils will have sufficient iron levels; however, the soil biological activity is often low at a neutral pH. Therefore, the availability of Iron is highly dependent on the pH level. Generally, almost all micronutrients (with few exceptions) become less available with increasing soil pH.

Iron deficiency is known to be a common disorder in alkaline soils, which is causing reduced crop yields and reduced nutritional quality. Iron deficiency can be detected when new leaves are yellow with green veins (interveinal chlorosis) and are typically caused by increasing soil pH. Ideal soil pH levels for sufficient plant-available Iron are in slightly acidic soils in a pH range between 5,5 and 6,5. Crops that suffer from iron deficiency respond to a lack of Iron by creating an acidic environment around their roots which can cause a further imbalance in other essential nutrients.

Iron toxicity will start to occur when the pH levels of the soil drop below 5,5. Iron toxicity can be excessive fertilizer application rates or caused by problems with the irrigation water source.

Treating nutrient deficiency or toxicity is difficult, and at the stage where either toxicity or deficiency becomes visible, yield loss is often inevitable. To promote a healthy soil life, it is best to intervene before the crop shows any symptoms. Most important and effective to avoid yield loss is to analyze your soil throughout the season regularly. Especially with the focus on monitoring pH levels and keeping a healthy micronutrient balance on the field.

From now on, AgroCares Scanner solution will allow measuring Iron and Aluminium right in the field.  Would you like to learn more about the new AgroCares SoilCares Manager Advanced application, contact us via