Soil acidity is one of the most important factors for plant life and development. It is the pH of the soil that determines its physical and biochemical properties, and thus creates conditions that limit or promote the cultivation of crops. Also important is the fact that in addition to the biological characteristics of plants in relation to the pH level of the soil during their cultivation should take into account the interaction of nutrients with the soil environment. Soils, the soil reaction of which is close to neutral, are most favorable for physiological processes of crop growth, soil transformation of chemical elements into the most accessible form for plants and the entry of nutrients into the tissues of the plant body. They also provide neutralization of toxic to plants mobile forms of iron, aluminum and manganese.
Soils with an acid reaction of the soil solution affect not only the degree of solubility of the applied fertilizers, but also the level of availability of nutrients necessary for proper nutrition of crops. Many years of agricultural experience confirm that for plants are the easiest to absorb nutrients in the soil, with the pH in the range of 6,5 to 7 units. This is especially important for young plants.
Fig. 1 – Influence of soil pH level on the availability of macro- and microelements for plants
Compost application is an organic method of land reclamation. Unlike chemical ameliorants (lime and gypsum), compost has a complete set of organically available macro- and microelements in its structure. Whereas when using chemical complex fertilizers, the availability of nutrients is about 30% under optimal agro-climatic conditions.
Over the past 20 years, farmers have significantly reduced the application of organic fertilizers, they have been replaced by the use of complex chemical and nitrogen fertilizers. It is known that when nitrogen fertilizers are applied, nitrogen binds to CaO, which directly regulates the level of soil acidity. As the accumulation in the soil solution of toxic elements, the absorption of which by plants in an acidic environment increases, over time, their excess is formed. It can reach toxic levels. And in the future it can lead to plant death. In soils with a low pH value, the assimilation of nutrient cations by the root system is also inhibited, and the activity of root bacteria, which produce organic nitrogenous substances, is suspended, enriching the soil with nitrogen and providing nitrogen nutrition to crops. When the acidity level is reduced to 5,5 units, the availability of potassium, magnesium, and molybdenum decreases. The process of nitrification of assimilation of nitrogenous substances in the soil is slowed down. Thus, the efficiency of nitrogen application by applying it to the soil as a fertilizer is reduced by −25%, potassium −33%, and phosphorus −50%. Such losses cause significant material damage to agricultural enterprises, farms and amateur gardeners due to poor nutrient consumption by plants. To neutralize the acidity and enrich the soil with nutrients, it is recommended to apply organic fertilizers. Compost is the most effective. It has a balanced amount of micro- and macronutrients, namely: NPK, S, Ca, Cu, Fe, Zn in sufficient quantities to provide basic nutrition for crops.
Neutralization measures are carried out on acidic soils. This allows you to get a neutral or slightly alkaline reaction medium. But in this case it is also necessary to correctly calculate the rate of compost. For example, for crops of grain group (barley, rye, oats, wheat) it is necessary to applicate about 5-6 t/ha, for corn 7-8 t/ha, for sunflower which reacts as much as possible to soil acidity and positively shows itself on potassium content in the soil, it is necessary to applicate 8-10 t/ha. With low soil acidity, the availability of some nutrients (potassium, magnesium, phosphorus, manganese, boron, zinc, copper) is significantly reduced, which leads to their deficiency and requires additional fertilizers to ensure normal crop productivity.
Doses of compost, determined by the value of metabolic acidity, are set experimentally and depend on the type of soil, particle size distribution of the soil and the content of humus in it. Doses of compost (presented above) are calculated on depth of arable horizon of 0-25 cm. At depth of arable horizon more than 25 cm the dose increases by 10%. When applicating compost in winter conditions, the dose is increased by 20%.
The use of compost will help to get an additional harvest and increase profits from 1 hectare by 30%.