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ENVIRONMENTAL SUSTAINABILITY ers’ share of consumer spending has dropped 13 percent, while other food-system sectors are en- To be environmentally sustainable, corn and joying record profits.soybean farms must protect soil and water. The As more contract arrangements develop be-two most common pollutants from corn and soy- tween agribusiness and farmers, the farmer in-bean production are soil sediments and nitrates. creasingly turns more decisions over to othersThe main source of soil entering waterways is and plays the role of indentured servant. Unlessbare ground created by tillage. Poor soil health, prices rise dramatically, corn and soybean pro-excessive fertilizer use, and inappropriate tim- ducers will need to find ways to differentiateing of fertilizer application cause nutrient runoff their products in order to tap markets that pay aand leaching. Additionally, tile drainage hastens premium.the movement of nutrients from fields to water-ways. Sustainable agriculture practices keep soil SOCIAL SUSTAINABILITYin the fields and prevent its movement into wa- Sustainable rural communities require a vig-terways. I will discuss these issues in more de- orous local economy based on successful, in-tail below. come-generating farms. Unfortunately, farmers dependent on corn and soybeans are losing their Figure 1. Number of farms during igure 1. Number far arms during farms in great numbers and moving elsewhere 20th Century the 20th Century to find jobs. Overall, the U.S. lost 219,500 farms between 1981 and 1986, as those fields were merged into larger operations (3). Figure 1 shows the decline in farm numbers from 1900 to 1997 (4). The perennial lack of profitability in com- modity-crop agriculture is evident in the ratio of prices paid for inputs to prices received for com- modities sold. Figure 2 shows declining ratios of sales prices to input prices (4). The net effect is lower profit margins for producers. With fewer people to support the local economy and pro- vide a tax base, businesses, churches, and social organizations close their doors. Also, schools and Source: National Agricultural Statistics Service, USDA. hospitals consolidate in larger towns and are less able to serve rural people. All of these trends affect the quality of life for those who remain on ECONOMIC SUSTAINABILITY the land. To be economically sustainable, corn and soy-bean farms must generate a reliable profit mar-gin every season. Given current economics, com-modity producers have little control over the Figure 2.price they receive for their products. The farm-ers become, in essence, “price takers,” in that theytake what they can get for their crop. With com-modity prices flat or in decline, and cost of pro-duction going up, it is easy to see why so manyfarms are going out of business. According to a 1998 report of the USDA Com-mission on Small Farms (2): “As farmers focusedon producing undifferentiated raw commodities,food system profit and opportunities wereshifted to the companies that process, package Source: National Agricultural Statistics Service, USDA.and market food.” The result: since 1980, farm-PAGE 2 //SUSTAINABLE CORN AND SOYBEAN PRODUCTION
Producers should also be aware that some $17/acre/year to pump irrigation water to com-buyers, including major grain traders like Archer pensate for lost soil water-holding capacity (8).Daniels Midland (ADM), have offered farmers The total cost of soil and water lost annually fromprice premiums for non-GMO crops, providing U.S. cropland amounts to an on-site productiv-a market niche for standard varieties. Whether ity loss of approximately $27-billion each yearthe non-GMO market continues to offer a pre- (6). These costs do not include the additionalmium, and whether it grows or shrinks over time, losses to society as a whole from reduced airremains to be seen. quality, pollution of surface waters, and dredg- SUSTAINABLE MANAGEMENT ing of streams and drainage ditches. Erosion is not the sole source of nutrient loss ALTERNATIVES from non-sustainable cropping. There is also sig- One way to increase the profitability of corn nificant loss to leaching. Nitrates, in particular,and soybean production is to reduce input costs pose pollution problems by leaching into ground-and build drought-hardiness through sustainable water or moving through tile drains into ditchesmanagement practices. The connection might and surface waters. Dr. Otto Doering of Purduenot be obvious at first but will become so with University estimates that widespread implemen-the understanding that one of the greatest threats tation of two best management practicesto agricultural sustainability is soil erosion and (BMPs)—cessation of fall fertilization and re-es-reduction in soil quality. Erosion is initiated by tablishment of riparian wetlands along water-raindrop impact on bare soil. Any management ways—could reduce nitrogen runoff by 20% (9). Runoff from fields farmed 1. Eff erosion org Table 1. Effect of erosion on organic matter, matter er, organically typically carries phosphorus, plant-av phosphorus, and plant-available water (7). wat ater less nitrate; in an Illinois study, researchers showed Erosion Organic Plant-available that nitrate levels in organic level matter Phosphorus water corn fields were half those % lbs./acre % found in conventionally Slight 3.0 62 7.4 farmed fields (10). The ex- Moderate 2.5 61 6.2 ception to this came shortly Severe 1.9 40 3.6 after a legume green-ma- nure crop had been incor-practice that protects the soil from raindrop im- porated in the organic fields in preparation forpact will decrease erosion and increase water corn planting; at that time, nitrate levels were theentry into the soil. Mulches, cover crops, and same in organic as in conventional.crop residues serve this purpose well. For more However, for farmers to effectively plug nu-information see the ATTRA publication Drought trient leaks caused by erosion and leaching, moreResistant Soil. than BMPs are required. Serious changes in pro- The major costs to the farm associated withsoil erosion come from the replacement of lostnutrients and reduced water-holding ability, ac-counting for 50 to 75% of productivity loss (6).Eroded soil typically contains about three timesmore nutrients than the soil left behind and is1.5 to 5 times richer in organic matter (6). Table1 shows the effect of slight, moderate, and se-vere erosion on organic matter, soil phosphoruslevel, and plant-available water on a silt loamsoil in Indiana (7). When erosion by water and wind occurs at arate of 7.6 tons/acre/year it costs $40 per year to Cover crops, Shinbone Valley, TN (photo printedreplace the lost nutrients as fertilizer and around with permission)PAGE 4 //SUSTAINABLE CORN AND SOYBEAN PRODUCTION
duction systems need to be made. Among the sustainability in that it maintains some degreemost effective changes identified to date are the of ground cover for much of the year but stillintroduction of conservation tillage, the use of involves some cultivation. Herbicide use is gen-cover crops, and longer crop rotations featuring erally reduced to a one-time band application onperennial forages. These are among the efforts the ridge, at or before planting.that will build soil health in the long term. For COVER CROPPINGmore information on soil health and buildingsoils, request the ATTRA publication Sustainable One of the most useful sustainable-ag prac-Soil Management. Also request Protecting Water tices employed in recent decades is the old butQuality on Organic Farms, which is useful for both undervalued practice of cover cropping. A coverorganic and non-organic producers. crop is a planting of (typically) grass and/or for- age legumes on a field between production sea- sons. Such plantings reduce erosion, build soil, Long-term rotations with legume sod and, in the case of legumes, fix nitrogen for sub- crops build the soil and provide a natural sequent crops. Cover crops are of exceptional reserve of nitrogen for subsequent crops value on otherwise bare winter soils, which can while reducing nutrient leaching. Soil is erode badly during rains and snow-melt runoff. especially resistant to erosion during the Another cover-cropping concept is the use of sod phases of the rotation. “catch crops.” The term refers to a non-legumi- nous cover crop, overseeded or planted shortly after the main crop harvest. Its principal pur- The production practices discussed below in- pose is to absorb soluble soil nutrients—espe-corporate many of the basic principles of sustain- cially nitrates—to prevent their leaching. Win-able agriculture, common across many types of ter annual grasses such as wheat, oats, rye, andfarming. These include plant diversity (achieved ryegrass are often used as catch crops. In sum-through crop rotation or intercropping); pest pre- mer, forage sorghums and buckwheat are some-vention (including weeds, insects, and diseases) times employed. For more on cover crops re-through habitat manipulation; nutrient cycling; quest the ATTRA publication Overview of Coversoil-building; and management flexibility—to Crops and Green Manures.name a few. There are any number of practicesand systems incorporating these principles from COMBINATION SYSTEMSwhich farmers can choose according to their in- Among the most promising systems to datedividual situation. Three are offered below. are those that combine conservation tillage with CONSERVATION TILLAGE cover crops. Dick and Sharon Thompson, who farm 300 acres near Boone, Iowa, built a herbi- No-till has caught on in many states as a wayto control erosion and reduce production costs. cide-free weed-management system aroundThe primary economic benefits come from lower ridge-till technology for corn and soybeans.labor and machinery overhead costs. Addition- Grain fields are overseeded or drilled in fall withally, costs of fuel and machinery maintenance are combinations of hairy vetch, oats, and grain ryelower. Yields under no-till typically hold steady as a winter cover crop. The vetch provides ni-while the soil quality builds. Over time, water trogen, while the grasses provide weed suppres-infiltration and soil tilth increase. With no-till, sion and erosion protection. The cover crop isevery field operation except planting and har- not tilled in prior to planting. Instead, the ridge-vesting is done with a sprayer. Often the low- till planter skims off the top of the ridge enoughest-cost system involves no-till with herbicide- to create a clean seeding strip. Subsequent passestolerant crops, though herbicide-free systems are with the ridge-till cultivator eliminate any coverbeing researched. crop in the inter-row area and help to re-shape Ridge-till is a good option in some situations. the ridges. The Thompsons estimate savings ofThis system could be considered intermediate in $45 to $48 per acre using their methods. //SUSTAINABLE CORN AND SOYBEAN PRODUCTION PAGE 5
Walking the Journey: Sustainable Perennial erennial Agriculture that Works. 1992. A 20-minute video about Dick and Sharon iculture Agriculture Thompson’s ridge-till farming system. Perennial crops (sod, trees, perennial grain Available for $39 from crops) are inherently far more sustainable than Instructional Technology Center annual crops. The main reason is that they do 121 Pearson Hall not require tillage to establish each year, hence Iowa State University soil erosion is reduced. Perennial forage crops Ames, IA 50011 like alfalfa, white clover, bromegrass, and fescue 515-294-1540. absorb and recycle nitrates much more effectively than row crops. Research in Minnesota has dem- Don and Deloris Easdale of Hurdland, Mis- onstrated that corn and soybean rotations havesouri, reduced their annual herbicide costs from leached-nitrate losses 35 times as great as fields$10,000 to less than $1,000 in three years on their in alfalfa or alfalfa-grass mixtures (12).300-plus acres of grain crops (11). They use hairy Agroforestry is a system that integrates pe-vetch, winter rye, or Austrian winter peas in com- rennial trees with annual crops such as corn andbination with their ridge-till system. They flail- beans or with perennial forages. Trees are inte-chop hairy vetch or winter peas ahead of the grated with crops to increase economic stabilityridge-till planter and plant directly into the re- through diversification. Some of the more com-maining cover-crop residue. This practice elimi- mon approaches include alley cropping andnated using a burndown herbicide. The legumes silvopasture. Alleycropping entails planting rowreplace much of the nitrogen needed for the corn crops between rows of high-value wood or nutor milo crop. Some liquid starter and liquid ni- trees during their establishment phase.trogen is placed below the seed at planting. They Silvopasture involves grazing livestock on for-more than recover the seed costs of their cover age growing under a widely-spaced tree stand.crops in savings on fertilizer and herbicide. The tree stand is thinned to allow enough sun- light to reach the forages growing below. For more information call ATTRA to request our Other Useful ATTRA Publications: Agroforestry Overview publication. • Sustainable Soil Management • Principles of Sustainable Weed Management • Intercropping Principles and Production Practices • Overview of Organic Crop Production • Organic Field Corn Production • Organic Soybean Production • Alternative Agronomic Crops • Conservation Tillage • Pursuing Conservation Tillage for Organic Crop Production • Protecting Water Quality on Organic Farms • Moving Beyond Conventional Cash CroppingPAGE 6 //SUSTAINABLE CORN AND SOYBEAN PRODUCTION
There are many alternatives to corn and soy- Symposium on Erosion and Soil Produc-bean cropping that involve creating a base of pe- tivity, December 10-11, 1984. Americanrennial forage. Once the cropland has been con- Society of Agricultural Engineers, Newverted to perennial sod, the problems of erosion Orleans, LA. ASAE Publication 8-85.and nutrient loss are minimized, making the 8) Troeh, F.R., J.A. Hobbs, and R.L.whole system much more environmentally sus- Donahue. 1991. Soil and Water Conserva-tainable. Among the options are grazing systems tion. Prentice Hall, Englewood Cliffs, NJ.for beef, poultry, sheep, and hogs. Many other 530 p.grazing ungulates—such as llamas and alpacas—can also be raised and marketed through a vari- 9) Stout, Cherry B., and John Pocock. 2000.ety of channels. ATTRA has much more infor- Hypoxia headaches. Prairie Farmer.mation on forage-based systems available on re- January. p. 42, 46, 48.quest. 10) McIsaac, G.F., and R.A. Cooke. 2000. Evaluation of Water Quality from Alter- References efer erences native Cropping Systems Using a Mul- tiple-Paired Design. University of Illinois1) Randall, Gyles. 2001. Intensive corn- at Urbana-Champaign, College of Agri- soybean agriculture not sustainable, U of cultural, Consumer, & Environmental M scientist says. Sustainable Agriculture. Sciences, Department of Natural Re- University of Minnesota Extension Ser- sources and Environmental Sciences, vice, College of Agricultural, Food, and Department of Agricultural Engineering. Environmental Sciences. Vol. 9, No. 10. 2 Available on the web at <http:// p. www.aces.uiuc.edu/~asap/research/2) U.S. Department of Agriculture. 1998. A stew_farm/home.html>. Time to Act. USDA National Commission 11) Easdale, Deloris. 1996. Controlling weeds on Small Farms, Washington, D.C. 121 p. and maintaining soil fertility with cover3) Goering, Peter, Helena Norberg-Hodge, crops. NCTD. National Conservation and John Page. 1993. From The Ground Tillage Digest. February. Vol. 3, No. 2. p. Up. Rethinking Industrial Agriculture. 28–30. International Society for Ecology and 12) Randall, Gyles, et al. 1997. Nitrate losses Culture. Berkeley, CA. 120 p. through subsurface tile drainage in4) U.S. Department of Agriculture. No date. conservation reserve program, alfalfa, and Trends in U.S. Agriculture. National row crop systems. Journal of Environ- Agricultural Statistics Service. Available mental Quality. Vol. 26. p. 1240–1247. on the web at <http://www.usda.gov/ nass/pubs/trends/index.htm>. By Preston Sullivan5) Baquet, Alan, Ruth Hambleton, and Doug NCAT Agriculture Specialist Jose. 1997. Introduction to Risk Manage- ment. USDA Risk Management Agency. Edited by Richard Earles and 19 p. Paul Williams6) Pimentel, D., et al. 1995. Environmental Formatted by Gail Hardy and economic costs of soil erosion and conservation benefits. Science. Vol. 267, February 2003 No. 24. p. 1117–1122.7) Schertz, D.L. 1985. Field evaluation of the effect of soil erosion on crop produc- tivity. p. 9–17. In: Erosion and Soil Productivity. Proceedings of the National //SUSTAINABLE CORN AND SOYBEAN PRODUCTION PAGE 7
IP100/5 The electronic version of Sustainable Corn and Soybean Production is located at: HTML http://www.attra.ncat.org/attra-pub/cornbean.html PDF http://www.attra.ncat.org/attra-pub/PDF/ cornbean.pdfPAGE 8 //SUSTAINABLE CORN AND SOYBEAN PRODUCTION