Aquest Link no existeix en el seu idioma, Veure en: English (en),
O utilitzar Google Translate:  

www.nrcs.usda.gov/wps/portal/nrc...use/worldsoils/

Healthy soils are the foundation of agriculture. In the face of mounting challenges such as a growing global population, climate change, and extreme weather events, soil health is critical to our future. Healthy soil is essential as global demands rise for food, fuel, and fiber. Soils also play a crucial role in food security, hunger eradication, climate change adaptation, poverty reduction and sustainable development.