In fact, soil should be thought of as a critical resource for plants, a resource that must be conserved and managed with increasing care. In many parts of the world soil has been degraded or actually lost, causing once green and productive regions to become biological deserts, in a process known as desertification . Soil depth or volume limits rooting zone but also the absolute amounts of water and nutrients available for plant growth. Soil texture, which is in large part a consequence of particle size, affects soil water and elemental nutrient content and availability. Permeability of a soil refers to the capacity for water to infiltrate between soil particles, but also to penetrate the soil and move through various soil horizons.
Soils are a renewable resource, but one that is renewed only very slowly.
So for practical purposes we can say that the amount of soil available for life on earth is finite. The formation of soil involves the interaction of many processes, both living and nonliving, and is outlined below. The time scale from bed rock to productive soil may be thousands of years. We will then proceed to design experiments in which we test for effects of different soil environments on seed germination, seedling establishment and subsequent plant growth. A portion of the background information covered in this lab will focus on experimental design.