Soils in the water cycle

Soils store and filter water improving food security and our resilience to floods and droughts. 

Functional soils play a key role in the supply of clean water and resilience to floods and droughts. Water infiltration through soil traps pollutants and prevents them from leaching into the groundwater. Moreover, the soil captures and stores water, making it available for absorption by crops, and thus minimizing surface evaporation and maximizing water use efficiency and productivity.

Water is the “lifeblood” of agricultural practice worldwide

Improved soil moisture management is therefore critical for sustainable food production and water supply. Reduction of a soil’s capacity to accept, retain, release and transmit water reduces its productivity, whether of crops, pasture species, shrubs or trees. The great challenge for the coming decades will be the task of increasing food production with less water, particularly in countries with limited water and land resources. In order to minimize the impact of drought on food security, soil needs to capture the rainwater that falls on it, store as much of that water as possible for future plant use, and allow plant roots to penetrate and proliferate. Problems with or constraints on one or several of these conditions cause soil moisture to be a major limiting factor for crop growth. In fact, poor crop yields are more often related to an insufficiency of soil moisture rather than an insufficiency of rainfall.

What role can farmers play?  

By implementing sustainable agricultural practices, farmers can influence the structure and organic matter content of the soil to improve its water infiltration and retention. Poor and unsustainable land management techniques such as overcultivation, overgrazing and deforestation put great strain on soil and water resources by reducing fertile topsoil and vegetation cover, and lead to greater dependence on irrigated cropping. Sustainable agricultural and land management practices that can help to improve soil moisture retention capacity include residue covers, cover crops and mulching; conservation tillage; zero-tillage; conservation agriculture, use of deep-rooting, drought-resistant, or less water-demanding crops; capture of runoff; rainwater harvesting; and knowledge-based precision irrigation.

FAO in action

FAO is supporting governments and farmers around the world in order to maximise and sustain water resources through sustainable agricultural practices and better water management. Key initiatives include the Agriculture Water Partnership for Africa (AgWA), the Regional Initiative on water scarcity in the Near East and the Agricultural water management solutions project in sub-Saharan Africa and in India.

27/08/2015

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