There is an ever-present danger in irrigating farm land which is accentuated by the use of chemical fertilizers. It brings about the dreaded alkali disease of the soil which eventually causes sterility in the land and makes it unfit for growing crops. The soil actually dies. This is known only in tropical and sub-tropical lands. The overstimulation by chemical fertilizers seems to create an impermeability of the soil which brings an accumulation of these alkali salts.
Irrigation causes the bringing to the surface of capillary water charged with dangerous salts.
In Hunza, we have temperate conditions, and there would be no danger of the formation of alkali land, but even if it were located in the tropics the remarkable methods of the natives in farming would prevent such an occurrence. Soil erosion is unknown in this land and it is easy to see why. The soil is porous and spongy because it is rich with organic matter. The rain seeps in instead of running away, though there is, of course, a terrible dearth of rain, which amounts in some years to only two inches. In only five years of organic farming we have checked erosion on our farm.