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 Nino, and human activities which degrade and exhaust the natural systems of the planet such as deforestation, over farming and excessive water extraction. Over-grazing and excessive irrigation exacerbate soil degradation via erosion 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 (shiny leaves), smaller leaves, notably thicker stems and deep or wide root systems. Drought resistant species can be employed to facilitate restoration agriculture techniques, which include revegetation using specific plant assembliages and rotational and zonal grazing strategies, e.g. goat herds which graze fodder (equivalent to trimming bushes) at specific times, for specific periods, thus producing manure and urine to enrich the soil. 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 salt panning, and much higher water consumption, both contributing to drought and desertification.

Permacultural techniqes have been developed, tested and continue to be advanced in the Jordanian dessert by Geoff Lawton and his team, for instance the Greening the Desert project sites. Governments in drought affected regions increasingly adpot the same or similar strategies and invest in developing revegetation strategies for areas severely affected by drought and desertification.

Read the full article: Permaculture Association

Advertisements

Published by

Willem Van Cotthem

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