Drought is a critical lack in water supply or availability

 

Photo credit: Permaculture Association

IMAGE SOURCE : CSIRO [CC BY 3.0 ],
via Wikimedia Commons

Drought

Drought is a critical lack in water supply or availability. Causes include deficiency in precipitation, dry seasons and El Niño, and human activities which degrade and exhaust the natural systems of the planet such as deforestation, over-farming and excessive water extraction. Deforestation, over-grazing and excessive irrigation exacerbate soil degradation via erosion, excessive salinity, panning, leaching, and defoliation, subsequently this can bring desertification– which is excessive or total vegetation loss and complete exhaustion of the soil.

Many plants have a high degree of natural drought resistance, most easily identified by physical features such as a waxy cuticle (thick leathery leaves), a reduced number of leaf pores (stomata) succulent leaves, or none at all – where the stem takes over photosynthetic functionality, notably thicker stems and deep or wide root systems. Drought resistant species can be employed to facilitate restoration agriculture techniques which include : re-vegetation using specific plant assemblages, keyline design and rotational and zonal grazing strategies. These approaches applied to an area of land, can act to restore it to a state where it can be agriculturally productive and maintain the resilience, stability and diversity of a natural ecosystem again.

Food producing, perennial plants and trees, with drought resistant properties are increasingly recognised for their suitability in increasing community resilence and sustainability in drought affected areas. This approach; employing ecosystem services and natural processes, is proving to support a greater diversity of food crops, compared to more industrial approaches (such as greenhouses, irrigation and chemical fertilisation) which can have long-term negative effects such as excess soil salinity and salt panning, and much higher water consumption, both contributing to drought, devegetation and desertification.

Read the full article: Permaculture Association

 

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Published by

Willem Van Cotthem

Honorary Professor of Botany, University of Ghent (Belgium). Scientific Consultant for Desertification and Sustainable Development.