What is soil leaching?
soil leaching it is an erosive process caused by the washing of the topsoil by surface water runoff. In general, it occurs in soils without the vegetation cover protective, which decreases, to a high degree, its fertility over time.
Leaching is a frequent process in the soils of tropical and equatorial regions, as in these places the rains are more abundant and intense. The runoff caused by precipitation carries the surface materials from the soil to the lower areas. Precisely for this reason, this process is more significant in regions with greater declivity. In this way, the water "washes" the soil, carrying the nutrients available in it to the water table and water courses, favoring its impoverishment.
O weathering, process of transformation of rocks by disaggregation (physical) or decomposition (chemical) of their structures, is important for the genesis of soils, however, it happens naturally and gradually. The removal of vegetation cover - especially for agricultural activities - intensifies the erosion process and can
totally destroy the ground, leaving him unable to produce.
Cutting and burning expose the soil directly to the work of rain erosion
Consequences
The leaching process of soils, especially those intended for agriculture, can have consequences ranging from the decrease in the soil's restructuring power to its death.
The more materials the water takes, the less soil there will be and the faster plant roots will reach the bedrock, stagnating its growth;
The leached soil has its reduced water storage capacity, as it becomes shallower, thus the original vegetation or crops will feel the effects more intensely in the dry period;
When the rains are very intense, the water can reach the matrix rock and, as there is no more soil to penetrate, it can soak the ground, harming the vegetation or the cultivated crop;
Hill and mountain slopes in equatorial and tropical regions are more likely to suffer the leaching process, especially with the removal of the original vegetation cover. The flowing water during torrential rains freely transports the surface horizon of the soil and in a continuous process it can reach the matrix rock.
By Amarolina Ribeiro
Graduated in Geography
Source: Brazil School - https://brasilescola.uol.com.br/o-que-e/geografia/o-que-e-lixiviacao-solo.htm