Lesson

6. Water: Shaping our world

 

Water is vital for every living thing, and it has no replacement. Water shapes ecosystems, and the distribution of populations of organisms within those ecosystems. Water availability determines what kinds of species and populations can be supported. Agroecosystems are no exception, and are our water management within those systems have broad-ranging impacts. Freshwater is a limited resource on this planet, and currently agriculture is responsible for ~70% of freshwater use worldwide. Largely, we’re using that freshwater in an unsustainable way.

As said by Boelee et al. in the book Managing Water and Agroecosystems for Food Security, “The understanding of linkages between ecosystems, water and food production is important to the health of all three, and managing for the sustainability of these connections is becoming increasingly necessary to help in improving global food security (Molden, 2007). Changes in the global water cycle, caused largely by human pressures, are seriously affecting ecosystem health and human well-being (Millennium Ecosystem Assessment, 2005c; WWAP, 2012; see Chapter 5). For example, in key parts of the tropics, agriculture has continued to expand into forest and woodland areas (Gibbs et al., 2010), where it has caused reduced tree cover and soil compaction, which have led to reduced infiltration and higher runoff of rainwater, often causing severe erosion, salinization or other degradation processes (Ong and Swallow, 2003; Falkenmark et al., 2007). Ecosystem degradation therefore threatens the regulation of ecosystem services such as water quality and water flow. Likewise, water is a key driver of several ecosystem functions, including biomass and crop yields, as well as of various supporting and regulatory ecosystem services (Keys et al., 2012).”

In this Lesson, you’ll explore how water, climate and weather shapes your ecosystem, how to manage water in excess and as a limited resource, agroecosystems approaches to water management and the politics of water in our global system.

Learning Objectives:

  1. To examine your own ecosystem, and evaluate the climate and weather of your own particular agroecosystem.

  2. To determine, using the climate and weather regime for your area, whether you have a deficit or excess of water, and what water management practices are needed.

  3. To develop a water and temperature management plan for your particular site.

  4. To analyze water rights and water grabbing from a global standpoint, and to critically reflect on these practices.

Cited: Boelee, Eline. (Ed.) 2013. Managing water and agroecosystems for food security. Wallingford, UK: CABI. 192p. (Comprehensive Assessment of Water Management in Agriculture Series 10)