No-Till: The Quiet Revolution - Research - Washington State University

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NO-TILL PIONEER John Aeschliman beganexperimenting with the technique in1974 out of concern over the soil erosionthat was taking place in WashingtonState’s sloping Palouse region, wherehis farm is located.ANDY ANDERSONJohn Aeschliman turns over a shovelful oftopsoil on his 4,000-acre farm in the Palouseregion of eastern Washington State. Theblack earth crumbles easily, revealing a porousstructure and an abundance of organic matterthat facilitate root growth. Loads of earthwormsare visible, too—another healthy sign.Thirty-four years ago only a few earthworms,if any, could be found in a spadeful of his soil.Back then, Aeschliman would plow the fieldsbefore each planting, burying the residues fromthe previous crop and readying the ground forthe next one. The hilly Palouse region had beenfarmed that way for decades. But the tillage wastaking a toll on the Palouse, and its famouslyfertile soil was eroding at an alarming rate.Convinced that there had to be a better way towork the land, Aeschliman decided to experimentin 1974 with an emerging method knownas no-till farming.Most farmers worldwide plow their land inpreparation for sowing crops. The practice ofturning the soil before planting buries crop residues,animal manure and troublesome weedsand also aerates and warms the soil. But clearingand disturbing the soil in this way can alsoleave it vulnerable to erosion by wind and water.Tillage is a root cause of agricultural land degradation—oneof the most serious environmentalproblems worldwide—which poses a threatto food production and rural livelihoods, particularlyin poor and densely populated areas ofthe developing world [see “Pay Dirt,” by DavidR. Montgomery, on page 76]. By the late 1970sin the Palouse, soil erosion had removed 100percent of the topsoil from 10 percent of thecropland, along with another 25 to 75 percentof the topsoil from another 60 percent of thatland. Furthermore, tillage can promote the runoffof sediment, fertilizers and pesticides intorivers, lakes and oceans. No-till farming, in contrast,seeks to minimize soil disruption. Practitionersleave crop residue on the fields after harvest,where it acts as a mulch to protect the soilfrom erosion and fosters soil productivity. Tosow the seeds, farmers use specially designedseeders that penetrate through the residue to theundisturbed soil below, where the seeds can germinateand surface as the new crop.In its efforts to feed a growing world population,agriculture has expanded, resulting in agreater impact on the environment, humanhealth and biodiversity. But given our currentknowledge of the planet’s capacity, we now realizethat producing enough food is not enough—© 2008 SCIENTIFIC AMERICAN, INC.KEY CONCEPTSn Conventional plow-basedfarming leaves soil vulnerableto erosion and promotesagricultural runoff.n Growers in some parts ofthe world are thus turningto a sustainable approachknown as no-till that minimizessoil disturbance.n High equipment costs anda steep learning curve,among other factors, arehindering widespread adoptionof no-till practices.—The EditorsSCIENTIFIC AMERICAN 71
[history]Agriculture milestonesThe roots of both no-till and tillage-based farmingmethods run deep, but eventually the latterapproach predominated, thanks to the evolution ofthe plow. Over the past few decades, however,advances in herbicides and machinery have madeno-till practical on a commercial scale.[THE AUTHORs]8000 B.C.Planting stick, the earliest version of no-till, enablesthe planting of seeds without cultivation.Scratch plowthe earliest plow, clears a path through the ground cover and createsa furrow into which seeds can be placed.6000 B.C.Draft animals replace humans in powering the plow.3500 B.C.Plowshare, a wedge-shaped implement tipped withan iron blade, loosens the top layer of soil.1100 A.D.?Moldboard plowhas a curved blade (the moldboard) thatinverts the soil, burying weeds and residues.Mid-1800sSteel moldboard plowinvented by John Deerein 1837, is ableto break upprairie sod.Early 1900sTractorscan pull multiple plows at once.1940s –1950sHerbicides such as 2,4-D,atrazine and paraquat enable farmers to manageweeds with less tillage.1960sNo-till seedersslice open a small groovefor seeds, keeping soildisturbance to a minimum.David R. Huggins (left) is a soilscientist with the USDA-AgriculturalResearch Service, Land Managementand Water ConservationResearch Unit in Pullman, Wash.He specializes in conservationcropping systems and their influenceon the cycling and flowof soil carbon and nitrogen. John P.Reganold (right), Regents Professorof Soil Science at WashingtonState University at Pullman,specializes in sustainable agriculture.This is his third article forScientific American.it must also be done sustainably. Farmers needto generate adequate crop yields of high quality,conserve natural resources for future generations,make enough money to live on, and besocially just to their workers and community[see “Sustainable Agriculture,” by John P. Reganold,Robert I. Papendick and James F. Parr;Scientific American, June 1990]. No-tillfarming is one system that has the potential tohelp realize this vision of a more sustainableagriculture. As with any new system, there arechallenges and trade-offs with no-till. Nevertheless,growers in some parts of the world areincreasingly abandoning their plows.Plowing AheadPeople have used both no-till and tillage-basedmethods to produce food from the earth eversince they started growing their own cropsaround 10,000 years ago. In the transition fromhunting and gathering to raising crops, ourNeolithic predecessors planted garden plotsnear their dwellings and foraged for other foodsin the wild. Some performed the earliest versionof no-till by punching holes in the land with astick, dropping seeds in each divot and then coveringit with soil. Others scratched the groundwith a stick, an incipient form of tillage, to placeseeds under the surface. Thousands of farmersin developing countries still use these simplemethods to sow their crops.In time, working the soil mechanicallybecame the standard for planting crops andcontrolling weeds, thanks to the advent of theplow, which permitted the labor of a few to sustainmany. The first such tools were scratchplows, consisting of a frame holding a verticalwooden post that was dragged through the top-STEWART HIGGINS Washington State University (Huggins and Reganold); wu hong epa/Corbis (scratch plow);ralf roletschek (moldboard plow); hugh talman Smithsonian Images (John Deere plow);lane lambert iStockPhoto (tractor); andy anderson (no-till seeder)72 SCIENTIFIC AMERICAN © 2008 SCIENTIFIC AMERICAN, INC.July 2008
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