pH control by humic acids II
The importance of pH in the context of soil and plants
Soil acidification is increasing worldwide, with serious consequences for agriculture and the fight against hunger. It is also a significant problem in Germany, as the first nationwide soil health study showed in 2018: only about a third of the arable land examined had an ideal pH value, while most soils were over-acidified.
Acidity issues in agriculture
The pH value directly influences the growth potential of crops. It determines the condition of the soil and affects the availability of nutrients for plants. Most crops develop optimally at a neutral or slightly acidic pH of 6.2 to 6.8, where nutrients are soluble, soil organisms are active and the soil structure is ideal. On the other hand, soil that is too acidic loses its looseness, retains less water and is poorly aerated. As a result, plants absorb fewer nutrients and microbial activity is reduced. As a result, important biological processes are greatly limited or do not occur.
Causes of Soil Acidification
Natural decomposition processes, the use of lime-depleting fertilizers and acid rain contribute to soil acidification. However, the addition of lime can partially counteract these effects. Lime significantly improves the soil environment: it dissolves nutrients, forms bonds between clay particles in the soil and thus promotes a stable structure. It also optimizes the supply of air, water and heat to the soil, increases the activity of soil organisms and thus supports various biological processes such as humus formation and mineralization.
Optimizing crop yields by adjusting pH with humic acids
Humic acids have similar soil improvement properties to lime, since they balance the pH of acidic soils and increase their buffering capacity. This means that acid rain has a less destructive effect on the soil. In addition, humic acids promote root growth and stimulate microbial activity in the soil, which in turn increases the rate of nitrification. In acidic soils where aluminium and heavy metals are present in dissolved form, humic acids act by binding and immobilising these elements. They support the formation of stable clay-humus complexes and thus reduce soil erosion. As an alternative to lime, humic acids have advantages, especially in strongly acidic soils, and are characterised by a long-lasting effect that improves the soil-plant system for up to five years.
Universal pH regulation with humic acids
Humic acids play an important role not only in acidic but also in alkaline soils. They act as natural chelating agents for metal ions, facilitating the uptake of nutrients by plant roots. Humic acids also dissolve phosphate-bound calcium and other nutrients and microelements, forming complexes with them and making them available in a form that can be used by plants.
