What is Soil pH?
Mathematically, soil pH is the negative logarithm of hydrogen in the soil solution. The neutral pH occurs when hydrogen (H +) and hydroxide (OH-) are equalized. Soil pH is measured on a display from 0 to 14. The pH of 7.0 is neutral. Under 7.0 the acidity increases in each unit and above 7.0 the pH in each unit goes towards alkalinity. Soil above pH 7 means alkaline soil, pH below 7 means acidic soil. pH is a logarithmic scale. A soil with a pH of 6.0 is 10 times more acidifying than a soil with a pH of 7.0. Soil having pH 5.0 has 100 times more acidifying effect than soil having pH 7.0. Caliche (Calcined) soil (carbonate-rich soil) formation is very high in climatic conditions where rainfall is limited. They are common under the soil surface.
Origin of Soil pHSoil pH is a product of the main material and the environment. Rainfall and temperature control the process that determines soil pH. Soil acidification occurs naturally in high rainy areas. Rain water can slowly dissolve some of the minerals that may change present. These elements are calcium, magnesium, potassium and sodium. These are called bases. Because their presence makes the soil pH alkaline. As the bases dissolve, precipitation filters the soil and makes them acidic by replacing them with hydrogen from rainwater. As a result of this process, the soil is now acidified. Calcium is the most important and most effective base for soil pH. Calcium which passes through the soil solution by washing causes hard well water or reaches the oceans by washing with rivers.
Carbonate Rich Soil FormationCaliche (Calcium = carbonate-rich soil) and / or another Calcium-rich horizon develops when precipitation is not sufficient to leak Calcium and Magnesium Carbonates from the soil surface to the ground water. The depth of the caliche depends on the depth of the leak. This depth, determined by the annual rainfall, is determined by the precipitation season and soil structure. Caliche (Calcine-rich soil) depth increases as precipitation and sand increases. Soil leveling or erosion simply exposes Caliche and / or Calcium-rich horizons. These areas have alkaline pH and are lighter than acidic soils. Soil organic materials are less and more difficult to process. These carbonate rich layers generally cause problems with pH and soil tillage. Agricultural practices (fertilization, irrigation, etc.) also contribute to the acidification of the soil. For example, ammonium and urea nitrogenous fertilizers acidify the soil. Protein and other nitrogen-containing compounds are converted from ammonia to ammonia in organic fertilizers. Ammonium nitrogen is also converted to Nitrate, leaving the soil with an acidifying effect of H + ions. Reviews
Soil Nitrogen Exchange AcidityOrganic Nitrogen Ammonium = ammonification Nitrate + 4H = nitrification Organic Nitrogen azot nitrogen suitable for plant = mineralization
Seasonal Soil pH ChangesSoil pH is seasonally variable. High soil pH (alkalinity) or low pH (acidity) was measured at the end of winter or before fertilization and at the beginning of spring. In sandy, low organic soils, the soil pH may drop by more than 1 unit (eg 7.2 to 6.2). The organic matter is low or very acidic at the beginning of the growing season in low-sand soils where the precipitation is low. Soil pH is reduced with increasing biological activity and fertilization due to soil temperature. The buffering capacity of the soil determines the level of seasonal pH changes. Soils containing significant amounts of clay and / or organic matter undergo small seasonal pH changes (around 0.3 units) by buffering the pH change. It is important to consider seasonal pH irregularities when monitoring the soil acidification program. Soils with less miles, clay and / or organic matter and soils below pH: 7.5 may vary from 1 unit to 2 units. Soils containing carbonate have a buffering power against pH changes and do not undergo major seasonal changes.