What benefits can liming acidic soils bring us? Part I

The soil reaction represents the amount of hydrogen ions (H⁺) in the soil solution. The more hydrogen ionsare retained by the exchange complex of the soil, relative to the basic ions (Ca²⁺, Mg²⁺, K⁺), so much the more acidic the soil. Although mainly hydrogen is seen as the causative agent of the acidic soil reaction, the presence of aluminum (Al³⁺) ions should also not be neglected.

The main factors that lead to acidification of the soil are: 📍 Rainfall/irrigation.Water interacts with carbon dioxide from the air to form carbonic acid. It is a weak acid and after ionizing hydrogen and bicarbonate ions are released. The released hydrogen ions replace the calcium ones from the soil colloids, which leads to acidification of the soil.📍 Nitrogen fertilizers.Nitrogen fertilization also affects the soil reaction. Nitrogen sources (synthetic nitrogen fertilizers, manure, legumes) contain or form ammonium ions. If ammonium ions are not absorbed by plants, they are converted to nitrates in the nitrification process, in which hydrogen ions are released into the soil. On the other hand, nitrates that are introduced with fertilizers or formed in the nitrification process can interact with calcium, magnesium and potassium and be washed out of the topsoil in depth. As these base cations are removed from the soil complex, their place is taken by hydrogen ions and soils become more acidic.📍 Plants.Legumes such as soybeans, alfalfa and clover absorb a greater amount of cations than anions. In this process, plant roots release hydrogen ions to maintain the electrochemical balance in the tissues, which also leads to acidification of the soil.Why is an acidic soil reaction harmful?Low pH interferes with normal root nutrition and plant development mainly in two ways. On the one hand, the high concentration of hydrogen ions can directly damage the root cells, and on the other hand, hydrogen competes with the absorption of the remaining cations (calcium, magnesium, potassium, ammonium, etc.). Also, when the soil reaction reaches values below 5.5 and especially below 5.0, aluminum and manganese in the soil become much more soluble, often being able to reach levels where they become toxic to plants.Another adverse effect is that at low pH values, phosphorus forms insoluble compounds with aluminum, iron and manganese. which are precipitated. This leads to plant deficiencies, respectively — to unsatisfactory yields.Plant requirements for soil response.Cultivated plants have some differences in terms of the soil response in which they develop best. There are crops that prefer a more acidic soil reaction (blackberries, raspberries, blueberries) and those that develop better with an alkaline reaction (legumes), but for most field crops grown in our country, the optimal soil reaction is from slightly acidic to slightly alkaline (6.0-7.8).❗ Stay tuned for the second part of the material, where we will show you a real example from our practice and you will understand why whitewashing brings a number of benefits.

If you want to find out more right now, you may refer to our agronomists!