Leaching (agriculture)

When leaching is known in soil science a soil-forming process, go into solution in which substances in the soil and this solution is removed by seeping water.

Salts are dissolved by hydration, most other minerals - particularly carbonates and substantially less soluble silicates - by hydrolysis. Most minerals are barely soluble in pure water. However, most small amounts of carbonic acid and humic acid are dissolved in water, making the solution of many minerals is facilitated. Soil acidification intensified accordingly, the washout. Due to the different solubility occurs at a temporal differentiation of soil formation, so that succession can develop different types of soil in one place.

The leaching results in the soil profile to a horizontal differentiation, thus contributing to the formation of soil horizons. One of the fastest soil forming processes is the decalcification, ie the leaching of the soil present finely divided lime. Substances that are washed in the topsoil can be reprecipitated in the subsoil. This is particularly the podsolization the case, when displaced in this manner, humic substances and iron and manganese oxides.

If the solute is not precipitated again, but removed with the ground water, the leaching of chemical weathering contributes. This should not be confused with the mechanical action of the flowing water. Therefore, the reaction leading to the formation of karst limestone weathering, consisting of the steps of carbonic acid weathering and removal solution, sometimes referred to for short as leaching.