Soil Regulates Circulation of Water on the Planet Earth

Abstract

The circulation of water on Earth is composed of several basic processes. Water vapor existing in the air condenses into small waterdrops that fall to the Earth’s surface as rain or snow. The water either soaks into the ground or it flows on the surface into rivers – the majority of which empties into the ocean. Moreover, portions of infiltrated water flow to the rivers as groundwater. Water evaporates from oceans, from rivers on its run to the ocean, and directly from the soil surface or indirectly from the plants as transpiration. When water circulates back into the atmosphere as water vapor, it is ready to take another run within the above processes, collectively known as the hydrologic cycle. If there were no soil, infiltration would not exist. A net of dry riverbeds, called wadi in a desert, would quickly conduct rainwater. During the great majority of time, landscapes would be without water, similar to today’s desert regions. Without any water on land, there would be no chance for plants to grow and animal life would not exist. Indeed, life on land would be restricted to some microbes resistant to dryness existing for the majority of times when rainfall does not occur. With rain seldom appearing, large territories without rain could exist for several years. Frequent rains happening several or more times in the month would occur only in narrow strips of land at the shore. The remaining regions of continents without soils that have no porosity to catch and store water in its pores during rainless periods would always remain dry and could not contribute to evaporation.