Soils around the world each have their individual characteristics, which are influenced by such environmental factors as climate, topography, parent material, biology and time. The black soil mainly found extensively across the Eurasian Steppe and other regions with a semiarid steppe climate is soft, rich in both organic matter and mineral nutrients, and highly productive. The lack of rain in deserts means that nutrients do not get washed away, so the soil is rich in minerals. However, some land has been degraded by human activity; for example, irrigation has caused salinization in Kazakhstan, while overcultivation in Niger has been responsible for wind erosion. Scientists are engaged in ongoing efforts to understand the diversity of soils and explore measures that also take into account sociocultural characteristics.