2008 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, enzyme activity and fatty acid methyl ester (FAME) profiles. We participated in a multi-location project to assess the vertical distribution of corn biomass, which is relevant to harvesting corn stover as a bioenergy feedstock. Our work quantifying the effects of residue removal on soil properties and soil productivity has received international attention, including many invited presentations and popular press articles. These activities address Problem Areas 1 (Understanding and Managing Soil Biology and Rhizosphere Ecology), 3 (Soil Carbon Measurement, Dynamics, and Management), 4 (Nutrient Management for Crop Production and Environmental Protection), and 6 (Impact on Soil of Residue Removal for Biofuel Production) in the NP202 Action Plan.
In Objective 2, a second site was characterized both before and after soil movement for landscape restoration. Crop emergence, development, and yield monitoring are ongoing at both restoration sites. Detailed digital elevation maps were constructed for both sites and modeling is underway to predict soil erosion occurring after soil movement for landscape restoration. A field experiment is being conducted to evaluate herbicide fate and transport in rehabilitated and undisturbed landscapes. A manuscript discussing the impact of intra-landform soil movement on soil properties and soil productivity has been submitted to Soil and Tillage Research. Several other papers reporting herbicide fate and tillage erosion rates in spatially-variable, topographically-complex landforms were published in peer-reviewed journals and presented at national and international meetings. Significant progress in understanding the fate of agricultural fumigants and their impact on the environment was reported in a number of peer-reviewed papers. These activities address Problem Areas 9 (Remediation of Degraded Soils), 7 (Managing Pesticides in Soil), and 8 (Control of Soil Erosion) in the NP202 Action Plan.
Balancing Soil Quality and Biomass for Bioenergy
Achieving sustainable food, fiber, and energy production requires a balance among competing uses of non-grain crop biomass (for example, straw and corn stover). Using models and empirical information, it was estimated that the biomass input required to maintain soil organic carbon contents exceeds that needed for erosion control. Constraining non-grain crop biomass harvest to maintain soil organic matter/carbon rather than to limit soil erosion will decrease the amount of biomass available as a bioenergy feedstock. Information on the importance of non-grain crop biomass in maintaining soil quality and agricultural productivity was presented in the context of harvesting biomass for bioenergy at eleven national and international meetings. This information will aid producers, energy cooperatives, policy makers, and policy implementers (e.g. NRCS) in making informed decisions on how to sustainably use crop biomass for bioenergy production. This accomplishment addresses Problem Area 6 (Impact on Soil of Residue Removal for Biofuel) in the NP202 Action Plan and Components I (Ethanol) and IV (Energy Crops) in the NP307 Action Plan.
Predicting Herbicide Fate
Sorption coefficients (measures of the extent to which pesticides are bound to the soil) vary across landscapes; accounting for this variation could reduce uncertainties in regional-scale assessments of pesticide behavior. We measured the sorption of two common herbicides, 2,4-D and glyphosate, throughout an eroded hilly field in which soil properties are highly variable. Herbicide sorption coefficients are dependent on soil properties and thus were also highly variable. We found that including information about slope curvature and other factors describing the terrain could improve predictions of herbicide sorption in this field. These results suggest that this approach may help increase the accuracy of pesticide fate models, and these results will help guide additional research to determine how including information about field terrain can improve pesticide fate models. This accomplishment addresses Problem Area 7 (Managing Pesticides in Soil) in the NP202 Action Plan.
Modeling Soil Movement by Tillage
Soil movement by tillage (tillage erosion) is recognized as a major eroding force that affects soil productivity and environmental quality by redistributing soil mass and soil constituents in the landscape. In this study, a conceptually-simple diffusion model (TillTM) was developed to simulate the tillage erosion process. This model was used to describe the redistribution of soil mass and soil organic carbon (an example soil constituent) on landscapes with different topographic features. We showed that the TillTM model can precisely estimate the pattern of soil constituent redistribution by tillage, but may require detailed field measurements to accurately represent the changing contents of soil constituents in the landscape. These results will enable land managers, extension personnel, consultants, and agricultural researchers to predict the effects of tillage erosion on the movement of soil mass and soil constituents in landscapes and to better describe landscapes affected by tillage erosion. These results will be useful in designing and evaluating cropping practices to reduce soil erosion. This accomplishment addresses Problem Area 8 (Control of Soil Erosion) in the NP202 Action Plan.
Rehabilitating Eroded Landscapes
In hilly landforms subject to long-term cultivation, erosion has removed topsoil from upper slope positions and accumulated topsoil in lower slope positions. Given the importance of soil erosion on productivity, an intuitive approach to reduce crop yield losses in eroded fields is to reverse soil erosion by moving soil from areas of soil accumulation back uphill. These experiments measured the effect of soil-landscape rehabilitation on soil properties and soil productivity. Results indicate that addition of accumulated topsoil from lower slope positions to eroded upper slope positions can result in large yield increases in upper slope positions and more consistency in crop yields across the landscape. Extension personnel, growers, crop consultants, regulatory agencies, and other scientists can use this information to better predict crop yield responses to soil properties and landscape position in eroded areas, to develop approaches to increase the productivity of eroded soils, and to recommend methods to remediate or restore eroded landscapes. This accomplishment addresses Problem Area 9 (Remediation of Degraded Soils) in the NP202 Action Plan.
5.Significant Activities that Support Special Target Populations
|Number of Non-Peer Reviewed Presentations and Proceedings||3|
|Number of Newspaper Articles and Other Presentations for Non-Science Audiences||1|
Li, S., Lobb, D.A., Lindstrom, M.J., Papiernik, S.K., Farenhorst, A. 2008. Modeling tillage-induced redistribution of soil mass and its constituents within different landscapes. Soil Science Society of America Journal. 72(1):167-178.
Sakaliene, O., Papiernik, S.K., Koskinen, W.C., Spokas, K.A. 2007. Sorption and predicted mobility of herbicides in Baltic soils. Journal of Environmental Science and Health Part B. 42:641-647.
Zheng, W., Gan, J., Papiernik, S.K., Yates, S.R. 2007. Identification of volatile/semivolatile products derived from chemical remediation of cis-1,3-dichloropropene by thiosulfate. Journal of Environmental Science and Technology. 41(18):6454-6459.
Papiernik, S.K., Yates, S.R., Koskinen, W.C., Barber, B. 2007. Processes Affecting the Dissipation of the Herbicide Isoxaflutole and Its Diketonitrile Metabolite in Agricultural Soils under Field Conditions. Journal of Agricultural and Food Chemistry. 55:8630-8639.
Spokas, K.A., King, J., Wang, D., Papiernik, S.K. 2007. Effects of soil fumigants on methanotrophic activity. Atmospheric Environment. 41:8150-8162.
Farenhorst, A., Papiernik, S.K., Saiyed, I., Messing, P., Stephans, K.D., Schumacher, J.A., Lobb, D.A., Sheng, L., Lindstrom, M.J., Schumacher, T.E. 2008. Herbicide sorption coefficients in relation to soil properties and terrain attributes on a cultivated prairie. Journal of Environmental Quality. 37:1201-1208.
Lindstrom, M.J. 2006. Tillage erosion: Description and process. In: Lal, R., editor. Encyclopedia of Soil Science. 2nd edition. New York, NY: Taylor & Francis. p. 1776-1778.
Lachnicht Weyers, S.L., Schomberg, H.H., Hendrix, P.F., Spokas, K.A., Endale, D.M. 2008. Construction of an electrical device for sampling earthworm populations in the field. Applied Engineering in Agriculture. 24(3):391-397.