On the northern rim of the region, the height of the Himalayas restricts the warm moist monsoon air from moving across the mountain range. The Himalayas act as a precipitation barrier and create a strong rain shadow effect for Tibet and Western China. The monsoon is responsible for much of the rainfall in South Asia.
Permeability id a scientific index of the soil to have air and water pass through the soil pore and spaces. As clay soils have a fine texture, with loamy soils moderately textured and sandy soils coarsely textured thus permeability changes from slow to rapid.
As sandy soil is highly permeable i.e 5.0 cm per hour and clay soils having the least i.e 0.05 permeability. Loamy soil is composed of sand, silt, and a smaller amount of clay.
From an agricultural perspective, the soil permeability depends upon the percentage of the see-page and the chemical makeup of the soil. Thus crops can grow more easily this type of soil as the particle size is minute and fine.
