Soil salinity rises due to constant irrigation in arid lands, will this method change the outcome?
Q Soil salinity rises due to constant irrigation in arid lands, will this method change the outcome?
A The Arizona basin is the bread basket of the USA, Constant irrigation here has led to the creation of a salt pan system, where the land is rapidly failing to maintain crop production. This is not a new problem. The Atacama desert in Chile is littered with the mummified remains of farmers who must have exhausted the soils in the same way, Here there are huge areas covered in a thick crust of salt cake. The problem arises predominantly where water is mined from non-renewable underground reserves or fossil water as it is known. This water dissolves the minerals from the soil over thousands of years and where it is used, the high evaporation rates boil off the water leaving the salts behind. Constant irrigation using this method leeches away organic material and builds up the salts at the surface. Another factor is that the constant use of underground water lowers the water table. This causes sea water to infiltrate the reserve, further increasing the salinity, leading to famine and starvation.
The Oasis Solution is to import water that has a very low salt content but a very high organic and nutrient content. Using this water to grow forests and maintain agriculture will not produce high concentrations of salts, and the salts it does leave in the soil will be exploited by trees, locking them away in the timber for many years.