[JADAM] On the Problem of Soil Salinity by Youngsang Cho
I read the book JADAM Organic Farming on the problem of salt accumulation in soil. The author begins with an important observation where acid rain is destroying land in farms (that is, our fields) but not land in nature. How is it possible that, in nature, the soil receives acid rain with all its pollutants but still none accumulates? He explains that:
Unlike cultivated soil, when acid rain falls on natural soil, the moisture seeps in deep. As it does so, it meets a huge number of various microorganisms which act on the pollutants and purify the water. Rain water becomes cleaner and cleaner as microbes break down pollutants. Purified water then flows into aquifers, reaches rivers and oceans, then goes back into the sky. In nature, because material circulation is functioning properly, even if pollutants enter the soil, they cannot accumulate. The process is designed not to have salt accumulation.
The author expressed that the problem with our fields is that due to frequent use of heavy vehicles or any farming equipment, the soil has been compressed and thus forming a compacted soil layer. When rain falls, the water is trapped by this compacted soil layer. It does not flow down and instead stagnates at a short depth below the surface, then it slowly evaporates and leave salt behind along with all the accumulated chemical substances such as chemical fertilizers, pesticides, antibiotics and herbicides. When acid rain evaporates, it leaves behind pollutants and heavy metals in the soil. Thus, the author concluded, that to solve the problem of soil salinity is to get rid of the compacted soil layer.