National Geographic : 2008 Sep
FLASHBACK Losing Ground A man measures the former ground level arm-high in rural Roosevelt County, New Mexico, in 1957. Only the deep roots of native bluestem grass held this hill of sandy soil together; winds had carved the rest away. Back then farmers here used clean tillage, the practice of clearing the soil surface of plant debris, says Patrick Kircher, a Roosevelt County agricultural extension agent. "They also broke down the ground to make a very fine seedbed. In country that's not very windy, that works well. But not here," he says. "Now we know to leave crop residue on the surface to help hold things in place." -Margaret G. Zackowitz t Flashback Archive Find all the photos at ngm.com. PHOTO:USDA NATIONALGEOGRAPHIC(ISSN0027-9358) ISPUBLISHEDMONTHLYBY THENATIONALGEOGRAPHICSOCIETY,1145 17THST.NW,WASHINGTON,DC 20036-4688.$34.00 A YEAR FORU.S. DELIVERY,$6.00 PERSINGLECOPY(INCLUDESPOSTAGEAND HANDLING).IN CANADA,AGREEMENTNUMBER40063649, RETURNUNDELIVERABLECANADIANADDRESSESTONATIONAL GEOGRAPHIC,PO BOX 4412 STN. A,TORONTO,ONTARIOM5W 3W2.UNITEDKINGDOMNEWSSTANDCOVERPRICE£3.99.PERIODICALSPOSTAGEPAIDAT WASHINGTON,DC, AND AT ADDITIONALMAILINGOFFICES.POSTMASTER:SENDADDRESSCHANGESTO NATIONALGEOGRAPHIC,PO BOX63002, TAMPA,FL 33663-3002.MEMBERS:IF THEPOSTALSERVICEALERTS US THATYOUR MAGAZINEISUNDELIVERABLE,WE HAVE NO FURTHEROBLIGATIONUNLESSWE RECEIVEA CORRECTEDADDRESSWITHINTWOYEARS.