2009 Annual Report
1a.Objectives (from AD-416)
The overall goal of this project is to develop soil and crop management systems that integrate biological, chemical, and physical principles to sustain agricultural production and environmental quality in the northern Great Plains. The project includes an investigation of the effects of management practices on soil biological, physical, and chemical properties; this information will be integrated with an assessment of one approach to restore eroded soil resources to indicate land management practices that may enhance long-term soil productivity, farm profitability, and environmental benefits in the northern Corn Belt. Specific objectives are to (a) determine the impact of management strategies on nutrient, soil carbon, and organic matter dynamics; and (b) to evaluate the impact of landscape restoration (soil movement from areas of soil deposition to areas of topsoil depletion) on soil properties, soil productivity, and environmental quality in severely eroded undulating landscapes.
1b.Approach (from AD-416)
Field experiments will be conducted in several sets of long-term research plots established by the North Central Soil Conservation Research Laboratory staff, including field plots implementing organic and conventional management practices that were established in 2002. The effect of organic and conventional land management practices on the structure of the soil biological community will be assessed in these plots through microbial biomass carbon and nitrogen and fatty acid methyl ester (FAME) profiles. The effect of nitrogen management practices on nitrogen availability will be evaluated by monitoring nitrogen mineralization. In separate field experiments, the soil and economic impacts of integrating corn stover harvest (for biofuel) into corn-soybean rotations will be evaluated by monitoring changes in soil properties and economic yield at different corn stover removal rates. Additional field experiments will be conducted to examine the effect of the timing and intensity of tillage, crop rotation, and planting date on carbon storage, crop growth, and economic yield. A five-year on-farm experiment will be conducted to evaluate the impact of landscape restoration by assessing (a) changes in soil chemical and physical properties (as a function of depth and landscape position) and topography that occur as a result of landscape restoration, (b) the productivity of restored and unrestored landscapes as a function of landscape position, (c) the economic costs and benefits of landscape restoration, (d) pesticide sorption and transformation in soils (as a function of landscape position and depth) in restored and unrestored landscapes, (e) the dynamics of soil biota (microarthropods) before and after soil movement for landscape restoration; and (f) the impact of landscape restoration and subsequent tillage on future soil erosion by tillage and water (using a predictive model).
In Objective 1, experiments were continued on schedule to: (1) quantify the effect of tillage management and crop rotation on soil carbon pools, (2) determine the similarities and differences in soil microbial dynamics under conventional and organic cropping management practices, (3) evaluate the impact of inorganic versus manure nitrogen management on nitrogen availability to crops, and (4) quantify the impacts of integrating corn stover harvest for biofuel production on soil properties. Soil samples were collected and analyzed for indicators of soil quality, including particulate organic matter, microbial biomass, and fatty acid methyl ester (FAME) profiles. Our work quantifying the effects of residue removal on soil properties and soil productivity has received international attention, including many invited presentations. Research was completed that demonstrated that no-till and strip tillage can increase profitability while protecting soil resources; this work was published in Agronomy Journal. The historical evolution of agricultural tillage practices was reviewed in the Encyclopedia of Rural America, demonstrating the progress toward less intensive tillage to maintain sustainable production.
In Objective 2, crop emergence, development, and yield are being monitored in response to variable soil properties at two soil-landscape rehabilitation sites. Information from one site, evaluating the impact of intra-landform soil movement on soil properties and short-term soil productivity, was published in Soil and Tillage Research. A field experiment was completed that evaluated herbicide fate and transport in rehabilitated and undisturbed landscapes. This work was presented at national meetings and is discussed in two manuscripts submitted to the Journal of Agricultural and Food Chemistry. Field and laboratory experiments were initiated to evaluate differences in weed dynamics in different portions of severely eroded landscapes in response to changing soil properties. An evaluation of the impact of crop rotation on soil aggregate stability and soil loss by water erosion is being continued. Field studies were initiated to quantify short-term erosion impacts on soil carbon dynamics. Several studies evaluating herbicide fate were completed and the results published in peer-reviewed journals.
Soil processes and residue harvest management. Changes in energy forms and energy use are being driven by finite oil reserves, rapidly rising energy costs, and increasing knowledge and concern about global climate change. Biofuel production is expanding using non-food plant materials such as crop straws, corn cobs, grasses such as switchgrass, and trees. Available literature was reviewed and synthesized to summarize potential risks to soil properties that may occur without careful planning and harvest management that can prevent or minimize risks. The information was presented at several regional and national meetings, and has been accepted for publication in a peer-reviewed book. This information will educate scientists, industry, producers, policy makers, and the general public of the benefits and risks associated with plant-based energy.
Water movement in soils of the northern Corn Belt. Information on the impact of soil properties, topography, and climatic conditions on water transport is required to improve predictions of contaminant transport and crop productivity. We evaluated the movement of bromide (a tracer of water movement) applied to the soil surface in the fall and in the spring in the northern Corn Belt. Approximately 60% of the applied bromide was lost over the winter by runoff and downward movement (leaching) beyond the root zone. Fall-applied bromide moved deep into the soil before the crop was established, whereas spring-applied bromide remained nearer the surface because plant root uptake and evaporation limited downward movement. These results suggest that little bromide was leached out of the root zone in the spring, and that plant uptake was a major route of bromide dissipation during the growing season. Other scientists can use this information to better predict water and contaminant transport in hilly landscapes, cropped soils, and soils that are frozen for significant periods.
Herbicide ineffective when applied in the fall. Some herbicides are prone to leaching and runoff under some conditions, resulting in widespread low-level contamination of water resources. We measured the rate of dissipation of the commonly-used herbicide S-metolachlor (trade name Dual) after fall and spring application to soils in the northern Corn Belt according to the label instructions. Most of the fall-applied metolachlor was depleted from the root zone during the winter, presumably by runoff and leaching (downward movement) out of the root zone. In these trials, fall-applied metolachlor dissipated prior to spring planting to such an extent that it provided no control of grassy weeds. The results of this research suggest that fall-applied metolachlor may not provide economic weed control and presents an increased risk of water contamination. This information enables better pesticide management decisions for the northern Corn Belt, and these results will be used to improve models that predict pesticide transport in variable landscapes and soils subject to freeze/thaw cycles.
Safe pesticide practices for rye production. Pesticides applied to soil can be taken up by plants and can contaminate water resources if they move downward (leach) to groundwater or run off the soil to surface water, so it is important to know how pesticides move after they are applied. We measured the leaching and plant uptake of the herbicides pendimethalin, clopyralid, mecoprop (MCPP), and dicamba following fall and spring application to soil cropped to winter rye. In most fall and spring trials, herbicide loss was less than three percent of the amount applied. None of the herbicides was detected in rye grain or straw at concentrations that exceed current EU or U.S. tolerances. The results of these experiments suggest that under typical climatic conditions, current use of the herbicides pendimethalin, mecoprop, clopyralid, and dicamba in rye production is not expected to result in unacceptably high concentrations of these herbicides in groundwater or in rye grain or straw. Growers, crop consultants, extension personnel, regulatory agencies, pesticide manufacturers, and others can use these results to plan effective and safe herbicide application strategies.
Alternative tillage systems are economically viable in the northern Corn Belt. While no-till crop production can provide conservation benefits in the northern Corn Belt, farmers continue to use conventional tillage due to concerns about yield reduction and economic risk. Reduced tillage systems such as strip tillage have been proposed as an alternative that may provide many of the conservation benefits of no-till while maintaining productivity and economic returns. We evaluated the economic performance of no-till and strip-till systems to determine if they can be profitable alternatives to conventional tillage systems for corn and soybean production in the northern Corn Belt. Results showed that average profits were higher with no-till and some strip-tillage alternatives than for moldboard plow tillage; these alternatives were also less risky than conventional chisel and moldboard plow systems. These results are important to farmers in the northern Corn Belt, demonstrating tillage practices that can increase profitability while protecting soils and the environment.
Reicosky, D.C. 2008. Tillage. In: Goreham, G., editor. Encyclopedia of Rural America. Vol. 2. 2nd edition. Millerton, NY: Grey House Publishing, Inc. p. 984-991.
Papiernik, S.K., Schumacher, T.E., Lobb, D.A., Lindstrom, M.J., Lieser, M.L., Eynard, A., Schumacher, J.A. 2009. Soil properties and productivity as affected by topsoil movement within an eroded landform. Soil & Tillage Research. 102:67-77.
Sakaliene, O., Papiernik, S.K., Koskinen, W.C., Kavoliunaite, I., Brazenaitei, J. 2009. Using Lysimeters to Evaluate the Relative Mobility and Plant Uptake of Four Herbicides in a Rye Production System. Journal of Agricultural and Food Chemistry. 57:1975-1981.
Farenhorst, A., McQueen, D.A.R., Saiyed, I., Hilderbrand, C., Li, S., Lobb, D.A., Messing, P., Schumacher, T.E., Papiernik, S.K., Lindstrom, M.J. 2009. Variations in Soil Properties and Herbicide Sorption Coefficients with Depth in Relation to PRZM (Pesticide Root Zone Model) Calculations. Geoderma. 150:267-277.
Zheng, W., Yates, S.R., Papiernik, S.K. 2008. Transformation kinetics and mechanism of the sulfonylurea herbicides pyrazosulfuron ethyl and halosulfuron methyl in aqueous solutions. Journal of Agriculture and Food Chemistry. 56:7367-7372.
Archer, D.W., Reicosky, D.C. 2009. Economic Performance of Alternative Tillage Systems in the Northern Corn Belt. Agronomy Journal. 101:296-304.
Dejong-Hughes, J., Johnson, J.M. 2009. Is Deep Zone Tillage Agronomically Viable in Minnesota? Crop Management. Available: http://www.plantmanagementnetwork.org/cm/element/sum.aspx?id=8026&photo=4562.