Saline soils are those that contain large amounts of dissolved salts, to the extent that a problem for the growth and development of plants. Salts commonly generate salinity, is formed by the anion: HCO3-, CO3-2, SO4-2, Cl-and cations: Ca +2, Mg +2, K +, Na +. The nitrate anion (NO3-) and ammonium cation (NH4 +) can participate in the generation of salinity, especially when applying high doses of nitrogen fertilizer or used large amounts of organic fertilizers. soil salinity is evaluated in the saturation paste extract, by measuring the electrical conductivity, ie the ability to transport electrons. A higher electrical conductivity higher salinity. In substrates and organic fertilizers, salinity is also assessed in the extract of saturated paste. In nutrient solutions, either for hydroponics for fertigation or foliar fertilizer, electrical conductivity is directly measured. The unit used above is mmhos cm-1 and recently handled dS m-1, in practical terms is the same, ie the conductivity value is the same in both units. To evaluate the type of salts in the soil, its concentration should be expressed in meq L-1. In the specific case of the sodicity of the soil, is necessary to know the cation exchange capacity of soil (cmol (+) kg-1) and the percentage of the capacity occupied by sodium (PSI).
for the formation of saline soils requires that you have a source of salts and conditions for the accumulation of them. The sources of salts are natural and artificial origin. Natural sources of salt weathering constitute the minerals, either by water or carbonic acid. Once produced the salts can be transported by water to the sites of deposition. This situation is described below:
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