Formation of Minerals and Soil

Science — Second Preparatory

Types of soil and their fertility

Type	Particle size	Property
Sand	The largest particles	Lets water pass quickly and does not hold water or minerals well
Silt	Medium particles	Fertile, and holds water and minerals well
Clay	The smallest particles	Holds a lot of water and becomes hard and poorly aerated when dry

Good farming soil (loam) is a mixture of sand, silt and clay in suitable proportions, with enough organic matter.
The Nile Valley soil is fertile because it contains Nile silt, which is rich in minerals and organic matter.
Desert soil is mainly sand and poor in nutrients, so organic fertiliser must be added before it can be farmed.

Formation of Minerals and Soil · 5 / 8