The remaining soil is compacted by trucks and machinery during construction. When the house is finished there is no attempt to reestablish a healthy soil profile. A thin layer of whatever is available is spread on the site and grass is planted. Healthy soils are composed of 45% mineral particles, at least 5% organic matter, 25% water, and 25% air space. Organic matter is critical for healthy soils it provides habitat and nutrients to organisms living in the soil. It binds soil particles into aggregates and improves the water holding capacity of soils. Soil is a dynamic living ecosystem teaming with organisms performing many vital functions. Nutrient exchanges between soil, water and organic matter are essential for the success of the ecosystem. If the nutrient cycles are broken the soil fertility declines and the soil eco system is destroyed.