2012 calendar - Sand Designs 'Out of this World' Special Edition to celebrate EARTH DAY 42nd Anniversary of Earth Day April 22, 2012. The world is in greater peril than ever. While climate change is the greatest challenge of our time, it also presents the greatest opportunity – an unprecedented opportunity to build a healthy, prosperous, clean energy economy now and for the future. Earth Day can be a turning point to advance climate policy, energy efficiency, renewable energy and green jobs. Earth Day Network is galvanizing millions who make personal commitments to sustainability. Earth Day is a pivotal opportunity for individuals, corporations and governments to join together and create a global green economy. Join the more than one billion people in 190 countries that are taking action for Earth Day. Crop Circles in Kansas Resembling a work of modern art, variegated green crop circles cover what was once shortgrass prairie in southwestern Kansas. The most common crops in this region—Finney County—are corn, wheat, and sorghum. One conservation measure is using water more wisely so less is drawn out of the aquifer. Farmers in this region have adopted a more efficient irrigation method, central pivot irrigation. Central pivot irrigation draws water out of a single well in the center of the field. Long pipes perched on wheels rotate around the pivot, showering the crops with water. Because the water falls directly on the crops instead of being shot into the air as occurs with traditional sprinklers, less water is lost to evaporation and more goes to nourishing the growing plants. Central pivot irrigation also creates perfectly circular fields, as seen in this image. The fields shown here are 800 and 1,600 meters (0.5 and 1 mile) in diameter. Image Credit: NASA