Ecology

Question

How do people grow crops in the desert when there is so little rain? Thanks (this is a test question for new experts who signed up in March or April)

Answer

<P><FONT size=3>Agriculture is important for the economy of the desert states and while there is very little water, or humidity, crops are successful in part because of irrigation and selective choices of seeds and crops.&nbsp; In Arizona there are approximately 7,300 farms and ranches that have average sizes of 3,630 acres.&nbsp; Their top crops are lettuce, cotton, and hay although they also produce cantaloupe, honeydew, spinach, broccoli, cauliflower, and watermelon.&nbsp; Many tree crops (oranges, lemons, limes, apricots, pistachios, avocados) have taken advantage of flooding but are beginning to change over to pressurized irrigation. &nbsp;Winter agriculture takes advantage of seasonal rains and cooler temperatures that satisfy growth requirements for cool season crops (lettuce, broccoli, cauliflower).&nbsp; Research on plant species has created or identified species that will perform better in the desert climate.&nbsp; For example, research has developed improved species such as Imperial lettuce and&nbsp;Sonora alfalfa. A lot of water is brought in through the Colorado River, from reservoirs in the foothills of nearby mountains.&nbsp; Farmers have invested in a variety of irrigation techniques, that includes pressurized and drip irrigation.&nbsp; Many farmers continue to use flood irrigation, basically because pressurized and drip irrigation methods are expensive to install. Pressurized&nbsp;irrigation systems include drip, subsurface, bubbler and spray, and fertilizer injection systems.&nbsp; These can be designed to travel on tracks or wheels, from center pivots, or a number of other ways.&nbsp; While flooding has enabled farmers to successfully raise crops in the dessert, they realize that changes are necessary to keep up with the increased demands for water.&nbsp;<BR><BR>The combination of warm winters and winter rains for winter crops makes growing crops in the desert desirable.&nbsp; Additionally, certain crops (watermelon, cotton, peppers) require higher temperatures found in the desert.&nbsp; The irrigation enables far mers to grow these summer crops.&nbsp; In some locations of the desert they are able to take advantage of summer seasonal rains, but that is mostly in the Sonoran Desert of southern Arizona. </FONT></P> <P><SPAN style="FONT-SIZE: 12pt; FONT-FAMILY: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: EN-US; mso-bidi-language: AR-SA"></SPAN>&nbsp;</P> http://cals.arizona.edu/pubs/general/resrpt1996/lettuce.html http://danrrec.ucdavis.edu/desert/home_page.html http://ag.arizona.edu/extension/cropproduction.html http://vrd.askvrd.org/services/answerschema.xml