Evolving Roles of Blue, Green, and Grey Water in Agriculture
Due to its multiple uses, water is a highly competed‐for resource. While the competition is mainly in the use of the resource, contestation over water resources is also demonstrated through how the resource is defined and described.
Terms such as water stress and water scarcity are commonly used in literature, and so are various colors that define water quality, including white, grey, yellow, and black water. Water that is useful for agriculture is distinctly known as blue or green water, with the latter increasingly gaining prominence in water planning for improved agricultural productivity. Proper management of green water has been shown to improve grain yields in Sub‐Saharan Africa by as much as 2.5 – 6 times.
The arid nature of Sub‐Saharan Africa, coupled with the high evapotranspiration rates, calls for improved management of green water, including reducing evaporation losses, reducing seepage, and increasing the water holding capacity of soils. The value of green water management in Sub‐Saharan Africa is further enhanced by its low‐cost nature when compared to irrigation, which is an area that Sub‐Saharan Africa has also been focusing on as part of the solutions to the increasing food needs of its growing population. Infrastructure for irrigation is costly and not affordable to the majority in Africa. In addition, irrigation can only benefit those communities near the water sources, whereas proper green water management can have benefits to all communities, including those far from a water source.
This issue of the Journal of Contemporary Water Research and Education published in December 2018, features an article written by Clever Mafuta (Programme Leader, Transboundary Waters, GRID-Arendal) titled "The Value of Green Water Management in Sub-Saharan Africa: A Review" (see pp 67-75).
Type: Partner Publications
Author: Clever Mafuta
Year of publication: 2019
Publisher: Universities Council of Water Resources and Southern Illinois University