Humidity and Rainfall - Agroecology: The Ecology of Sustainable Food Systems - page 84

sustainable animal-based food production. We will discuss
grazing systems in this context in Chapter 19, Animals in
Agroecosystems.

INTERNET RESOURCES

Climate Rainfall Data Center (CRDC) at Colorado
State University
rain.atmos.colostate.edu/CRDC

LESSONS FROM SUSTAINABLE SYSTEMS

Global Change Data and Information System
(GCDIS)
globalchange.gov
Comprehensive data sets on all aspects of global
climate change, including precipitation.

Irrigation technologies have been developed all over the
world to compensate for the vagaries of the rainfall factor,
but the ecological consequences of such technologies have
begun to manifest themselves in many ways. Soil erosion,
sedimentation, salinization, and loss of natural wetlands
and watershed systems are just some of the problems. It
is hoped that by examining the nature of humidity and
rainfall as we have done in this chapter, as well as the
examples of agroecosystems that work with local rainfall
conditions rather than against them, we can get a glimpse
of an important aspect of sustainability.
For a factor such as rainfall, nature can serve as a
useful model for developing a sustainable agriculture.
Much of present-day agricultural development has
approached the lack or excess of rainfall, intent upon
eliminating or altering conditions to fit the needs of the
cropping systems being introduced. This usually
involves high levels of external inputs of energy or
materials. There are many well-known examples of
massive irrigation, drainage, or desalination projects
that attempted to alter existing ecological conditions,
but achieved only limited success when evaluated in
terms of crop productivity, economic viability, and
social welfare. We need to intensify the search for ways
to accommodate agriculture to the natural variability
and unpredictability of rainfall.

Global Water Partnership
www.gwpforum.org/servlet/PSP
National Acid Precipitation Assessment Program
www.oar.noaa.gov/organization/napap.html

USDA Agricultural Research Service: National
Program on Water Quality and Management
www.ars.usda.gov/research/programs/pro-
grams.htm?NP_CODE = 201
United States Geological Survey
bqs.usgs.gov/acidrain/
On-line data and reports on acid rain, atmospheric
deposition, and precipitation chemistry.
The World's Water: Information on the World's
Freshwater Resources
www.worldwater.org

RECOMMENDED READING

Barry, R.C. and Chorley, J. 2003. Atmosphere, Weather, and
Climate. 8th ed. Routledge: London and New York. A
recently revised and updated edition, which emphasizes
the ways in which the complex interactions between
atmosphere and weather create world climates.
Bonan, G.G. 2002. Ecological Climatology: Concepts and Appli-
cations . Cambridge University Press: UK. This topic
integrates the perspectives of atmospheric science and
ecology to describe and analyze climatic impacts on
natural and managed ecosystems. In turn, it discusses
the feedback loop whereby the use and management of
land by people affects climate. The topic includes
detailed information on the science of climatology as
well as chapters on the interactions between climate and
terrestrial ecosystems, including agroecosystems and
urban ecosystems.
Glieck, P. 2005. World's Water, 2004-2005: The Biennial Report
on Freshwater Resources . Island Press: Washington,
D.C. The latest of a biennial series starting in 1998, this
comprehensive volume discusses global freshwater
resources and the political, economic, scientific, and
technological issues associated with them.
Nabham, G.P. 1982. The Desert Smells Like Rain: Naturalist
in Papago Indian Country . North Point Press: San
Francisco, CA. A sensitive look at how water is the

FOOD FOR THOUGHT

1. What are some of the benefits and detrimental

effects of irrigation as a means of overcoming
limiting rainfall, from the point of view of
sustainable agriculture?

2. How are rainfall patterns affected by topogra-

phy? How has agriculture been adapted to the
variation in rainfall patterns caused by topo-
graphic variation?

3. What are some of the possible ecological roles

of a dry season for ecosystems?

4. What is the best way to prepare an agro-

ecosystem for the unpredictable nature of
precipitation?

5. What are some ways by which farming systems

of the future might adjust to the probable
changes in rainfall patterns caused by global
climate change?