Nutrients availability at different pH value

The pH value measures the ratio of H+ ions to OH-base ions in the soil. If the soil solution has more H+, the soil is acidic. If the OH-dominates, the soil is alkaline. The equal balance between them is neutral and its value 7.0. The soil pH value interacts with the mineral nutrients. Availability is determined by the soil pH and varies for each nutrient. High or low pH causes toxicity and decreases microbiological life in the soil.

Sodium raises pH and destroys soil structure. High pH makes elements such iron zinc and manganese less soluble. Low pH leads to continuous acidification in the soil. Acidification can be the result of the excessive use of fertiliser, or it can also occur naturally. For example, a mass of vegetation in a warm and moist condition during decomposition produces high quantities of carbon dioxide. In another instance, acidic  cations in large amounts replace the natural nutrients and cause acidity in the soil. Strong and extremely acidic soils are deficient in calcium and magnesium. Alkaline and strong alkaline soils contain high levels of free limes. Extremely alkaline soils are usually sodic soils. The positively charged sodium ions attract the negatively charged soil particles. The soil particles move close to each other, which creates a soil compaction. As a result, the water infiltration into the soil is slow and organic matter dissolution is possible. Root penetration is also extremely difficult.