Grasslands cover up to 40% of Earth's land surface. Found between deserts and mountain climates. Divided into tropical and temperate types. Only about 10% of world's grass lands are protected
Native to African grasslands, reaching 7-8 meters in height. Forms bamboo-like clumps and requires low water and nutrients. Can grow from sea level to over 2,000 meters elevation. Produces about 40 tonnes of dry biomass per hectare annually
Topsoil is the upper layer of soil containing highest organic matter concentration. Extends to 5-10 inches depth and holds water and air. Contains high concentration of roots for plant nutrient acquisition. Hosts significant bacterial, fungal and entomological activity
Soil science studies soil as natural resource on Earth's surface. Main branches are pedology (formation, chemistry) and edaphology (soil-living interactions). Soil occupies pedosphere, one of Earth's spheres. Soil scientists collaborate with engineers, agronomists, and other disciplines
Soil erosion is the wearing away of the upper layer of soil. Natural agents include water, ice, wind, plants, and animals. Human activities have increased erosion rates 10-50 times worldwide. Water and wind erosion are responsible for 84% of degraded land
Agriculture affects ecosystems through various farming practices. Animal agriculture is more environmentally destructive than biomass farming. Experts use both means-based (farm practices) and effect-based (system impacts) indicators