378. 784 :37 :37 ing Practices for a Sustainable Agriculture in North Dakota North Dakota State University • Carrington Research Extension Center 3 7f 7 f' c; c 37 F37 Farming Practices for a Sustainable Agriculture In• North Dakota North Dakota State University S.A. Clancy, J.C. Gardner, C.E. Grygiel, M. E. Biondini, G.K. Johnson December, 1993 Contents Summary and Conclusions ........................................................................................ Summary 2 Introduction and Objectives ....................................................................................... Summary 4 Recognition of the Need for a More Sustainable Agriculture ............................... Summary 4 Socio-Economic Barriers to a Sustainable Agriculture in North Dakota .......................................... Summary 4 Evolution of Farming Practices to Achieve an Ecologically Sustainable System ........................................................... Summary 7 A Comparative Study of North Dakota Farming Practices ................................. Summary 10 The Overall Impact of Farming Practices ................................................ Summary 10 Summary of Methods Used ......................................................................................... Methods 1 References ................................................................................................................... References 1 Detailed Site Descriptions .............................................................................................................. 1 sponsored in part through the Northwest Area Foundation St. Paul, MN in cooperation with the North Dakota State University Carrington Research Extension Center Box 219 Carrington, ND 58421 phone 701 652 2951 special thanks to Karl Stauber, formerly with the Northwest Area Foundation, the Northern Plains Sustainable Agriculture Society, the Manitoba North Dakota Zero-Till Association, and the nine farm families who made this study possible Farming Practices for a Sustainable Agriculture in North Dakota Summary and Conclusions More information is needed on the ecological impact of various alternative farming practices in North Dakota. Farmers need comparative data to help them decide how to best meet the challenge of achieving economical yields while also maintaining high quality soils, water, and food. Policy makers need site specific information to help guide and shape environmental policy to be both broadly applicable and locally sensitive. This study was undertaken during the 1990 and 1991 crop seasons to compare what were deemed the most successful of alternative farm practices in North Dakota. Two farmer organizations, the Manitoba/North Dakota Zero-Till Association and the Northern Plains Sustainable Agriculture Society, both whom have championed alternative practices aimed at sustainability, helped define the objectives and choose actual farms to study. Successful farms representative of 1) practices predominately used, 2) maximizing use of conservation (or no) tillage, and 3) maximizing use of crop rotations to reduce (or eliminate) use of agrichemicals were chosen in eastern, central, and western North Dakota. As a benchmark of comparison, undisturbed prairie sites of similar soils were included within each region. The principle findings include the following: • Agricultural soils differed from prairie soils most in the east, and least in the west. Conventional practices had depleted soil organic matter contents by 71%,57%, and 27% from the level fond in prairie soils in the east, central and west, respectively. In addition, prairie soils generally had larger aggregates, lower bulk density, and lower quantities of nutrients in mineral forms. • The conventional farms generally performed the greatest amount of tillage, followed by the organic farms. Tillage tools used among farms were similar among the conventional and organic farms with the exception of plowing green manured alfalfa and sweet clover on the organic farms in the central and east. • The no-till and organic sites had a greater proportion of large soil aggregates in the central and east as compared to the conventional sites, making these soils less vulnerable to wind erosion. • Of the few farm sites which exceeded the erosion threshold, or T-value, conventional practices seemed most susceptible to erosion by wind, while the organic sites were near the threshold for erosion by water. The organic site in the east also exceeded the T-value for wind erosion. •Soil organic matter content among farm sites generally ranked no-till>organic>conventional. A notable exception was the conventional site in the west, which despite a wheat/black fallow rotation, maintained organic matter and other soil properties similar to the alternative sites through regular use of livestock manure. • Chemical fallow was mor-e efficient than black fallow at moisture storage (23 vs. 5%), but also contributed to excessive soil nitrate deep in the soil profile. Increased moisture capture and retention through reduced tillage must be accompanied by intensifying the crop rotation to avoid groundwater contamination. • The organic farms had the greatest crop diversity among all farm sites. Legumes were grown in rotation to provide nitrogen. Legumes were grown 3 out of 4 years in the east, 2 out of 4 years in the central, and 1 out of 4 years in the west region of North Dakota between 1988 and 1992 on the fields studied. • Organic and no-till sites generally had greater numbers of soil insects than conventional sites. Among specific species of insects, greater ground beetle populations at organic sites suggest a role they may play in biologically reducing the number of weed seeds. Farming Practices for a Sustainable Agriculture in North Dakota Summary 2 • No-till sites required the greatest use of pesticides, followed by conventional sites. Pesticide use also increased from west to east. Organic sites used none. • Water-use efficiency was generally greatest at no-till sites, but depended upon the crop grown. Overall 1990/1991 mean water-use efficiencies for the conventional, no-till, and organic sites were 476, 637, and 369 pounds of above ground dry matter produced per inch of precipitation. Beyond the influence of the farming practices themselves, fallow or production of an over­ wintering green manure crop were the factors which most reduced water-use efficiency as calculated. • Yields were similar among farm sites. Both alternative farming systems produced equal or greater wheat yields then the conventional farms, with no-till often achieving the greatest annual yield. •The total quantity of energy consumed in the conventional cropping system was reduced by 30% with no-till, and by 70% with organic farming systems. No-till practices shifted energy use from that expended for machinery and fuel to fertilizer and pesticides. Organic farms achieved their reduction through less tillage from use of over-wintering legumes, and no pesticide or fertilizer use. Comparing crop yield to the energy expended with an output:input ratio found the organic sites superior in energy efficiency at 9.0, no-till at 7.03, and conventional practices the least efficient at 5.4 . Conclusions from this study suggest that current farming practices can be further improved, resulting in greater environmental quality and less energy use while maintaining or even improving crop yield. The key to building soil quality seemed to depend upon a regular availability of sufficient quantities of organic matter. This was accomplished through reducing tillage, use of a crop rotation which included green manure and spreading of livestock manure or other soil amendments. Water quality seemed most threatened in reduced-till systems which did not balance precipitation with crop water use. Maintenance of soil surface cover and use of a variety of crops in rotation seemed to best promote biodiversity of animal life. Beneficial surface and soil insects provided a means of binding soil nutrients within the crop rooting zone and perhaps provided a means of reducing weed seed survival. Farmers considering adopting these alternative practices to reduce the environmental impact of their current cropping systems should also consider the possible risks which were detected in this study. Environmentally, the greatest vulnerability of the no-till system was water quality, while soil erosion was of concern with the organic system. Agronomically and economically, the no-till system was dependent upon the availability, price, and performance of pesticides and fertilizers. Conversely, the organic system was dependent upon the demand, price, and market stability for various alternative crops, such as rye, millet, and buckwheat required for crop rotation. Agricultural policy being shaped on both issues, through pesticide registration and international trade, will have a direct bearing on which alternatives will be the most attractive in the future. Over the long-term, specific innovations found among all these well-managed farms can be put to use in further developing more sustainable farming practices for North Dakota. Farming Practices for a Sustainable Agriculture in North Dakota Summary 3 Farming Practices for a Sustainable Agriculture in North Dakota Introduction and Objectives In North Dakota agriculture is vital since it remains one of the most rural and farming dependent states in the country. Changing technologies have had a dramatic impact on farming practices, which in turn have influenced