Location: Soil and Water Management Research2014 Annual Report
1. Develop irrigation and drainage strategies for emerging cropping systems in the North Central United States to protect water and soil resources. a. Develop methods to facilitate the success of living mulch systems through the use of supplemental irrigation, and evaluate their environmental impact. b. Develop N management strategies for large dairy operations to reduce nutrient losses through artificial subsurface drainage. 2. Reduce the potential adverse impacts of agronomic and horticultural practices on water quality: a) Identify and test innovative management practices; b) Determine factors that control the fate and transport of agrochemicals and contaminants of emerging concern. a. Identify and differentiate contaminants in surface water systems associated with the agriculture-urban interface in order to delineate contaminant sources and develop mitigation strategies. b. Compare water use requirements and characterize persistence, transport and loss pathways of contaminants with runoff from traditional and low-input turf managed with conventional or innovative practices. c. Develop management strategies to reduce nitrate-N leaching losses using fall-applied anhydrous ammonia. d. Determine factors controlling the fate and transport of agrochemicals and contaminants of emerging concern.
Development of agricultural management strategies and basic research on fate and behavior of agrochemicals are integral parts of both objectives. Research will be designed to maximize the information that can be used to attain multiple objectives. For instance, the research in Objective 1a and 1b will include development of irrigation and drainage strategies for emerging cropping systems that will require less N and reduce losses of nitrate-N to water bodies from agrochemicals, while Objective 2a will identify production management systems that minimize offsite transport of agrochemicals to surface water. Objective 2b will determine factors that control the fate and transport of agrochemicals and contaminants of emerging concern in the cropping systems with the irrigation and drainage strategies identified in Objective 1a and 1b, and in the production management systems identified in Objective 2a. The complementarity in fundamental processes studied, sample and data collection methods, and analytical methods across objectives will facilitate integration of results and provide important operational efficiencies. A cohesive, multidisciplinary team is needed to accomplish the presented range of research objectives.
Objective 1a: Large tension lysimeters were extracted in fall 2013 and reinstalled in spring 2014. Yield data and soil samples were collected in fall 2013 for use in running the Almanac model. A computerized infiltrometer system was designed and built to measure hydraulic conductivity in each plot of the experiment. A related extramurally funded experiment was initiated on a steeply-sloped field at the Rosemount Research Center, and runoff monitoring equipment was prepared for installation. Objective 1b: We continued monitoring subsurface tile drainage flow and water quality (4th year) for center pivot dairy slurry fertigation of silage corn and began comparing this crop/management scenario with alfalfa. A peer-reviewed manuscript was submitted comparing subsurface drainage sediment and dissolved phosphorus losses over two three-year periods: three years with open inlets in closed depressions (potholes) and three years with blind inlets. Objective 2a: Water, sediment and Polar Organic Chemical Integrative Sampler (POCIS) samples were collected and extracted by solid phase or accelerated solvent extraction. Analysis of contaminants (e.g. veterinary pharmaceuticals, hormones, and pesticides) by liquid chromatography tandem-mass spectrometry is substantially completed. Analysis of suite-1 contaminants are complete, suite-2 is mostly complete, suite-3 has just begun and suite-4 is planned. Approximately 80% of the POCIS samples have been analyzed. Principal Component Analysis of suite-1 compounds has been completed. Our results will provide tools to identify sources of surface water contaminants, providing insight for targeting mitigation approaches. Objective 2b: Studies on aminocyclopyrachlor adsorption to biochar and biochar-amended soils have been completed and a manuscript was written. Turf plots seeded with traditional creeping bentgrass or low-input fine fescue were maintained as a golf course fairway and treated with fungicides at full or partial label rates to evaluate the transport of fall-applied fungicides with spring snowmelt. Runoff flow rate and subsamples were collected, processed, and are awaiting extraction and chemical analysis. Extraction and analytical methodologies are being refined. Fertilizer and additional pesticide chemistries will be applied for evaluation of chemical transport with rainfall runoff. Analysis of runoff and evaluation of turf health will be performed to determine which turf system is most effective at reducing the off-site transport of contaminants with runoff. Objective 2c: We completed additional incubation experiments to study N dynamics as affected by adding high levels of fertilize N with and without biochar to different soils having contrasting textures and organic matter content and collected from different locations throughout Minnesota and also from New Zealand. We have observed that some soils generate substantially higher amounts of nitrite prior to its conversion to nitrate, and are currently examining possible microbial and chemical factors causing these differences. We delayed our field experiment by one year due to discovery of substantial heterogeneity in soil texture across the field resulting in significant yield declines in areas comprised of more coarse soil. We will need to redesign the plot layouts for next year. Objective 2d: Laboratory sorption experiments on indaziflam have been completed and writing of the manuscript is in progress.
1. On-farm environmental assessment of corn silage production with a winter rye cover crop and liquid dairy manure. The possible environmental impact of large dairies is a serious concern, because of the large amount of manure produced and the limited land area on which it is applied. This study was conducted to measure the offsite transport of nutrients from a silage corn field receiving dairy manure at permitted application rates, and to see if nutrient losses might be reduced through the use of a winter rye cover crop. The research was conducted in two adjacent tile-drained fields near a large dairy in west central MN. Manure was applied each fall following silage harvest at rates at average total nitrogen and phosphorus rates of 410 and 98 kg ha-1, respectively. We monitored tile drainage outflows for nitrate nitrogen (NO3-N) and dissolved reactive phosphorus (DRP). Nitrate nitrogen concentrations in the field that had a winter rye cover crop were lower (38 versus 53 mg/L), but there was no difference in DRP or total drainage flow. The cover crop also had no discernible effect on soil carbon levels. The rye did reduce spring soil nitrogen levels, but it also reduced the yield of the following corn silage crop by 16%. We conclude that a winter rye cover crop can reduce NO3-N losses, but the possible impact on subsequent silage yields makes it a risky option, at least in this region. These results will be useful in developing agronomic practices that reduce the environmental footprint of large dairies.
2. Alternative surface drainage technologies to drain agricultural closed depressions. In the prairie pothole region of the Midwestern U.S. cropland, subsurface drainage systems often include surface inlets in the bottom of low lying areas that drain ponded water after intense storms. The type of inlet design affects the transport of sediment, nutrients, agrochemicals, and bacteria from the field surface to the subsurface drainage system, bypassing the filtering capacity of the soil. This study was conducted to examine whether modifying the open inlets by burying them in gravel capped with 30 cm of sandy clay loam soil or in sand/gravel could reduce suspended sediment and phosphorus in drainage effluent. In Indiana, USA, closed depressions in adjacent fields were fitted with both open inlet tile risers and blind inlets and monitored for flow and water chemistry. Comparisons on a storm event basis during the growing season showed that suspended sediment loads were reduced by 64% for the closed versus open inlets. Soluble reactive phosphorus (SRP) loads were 50% less for the closed inlets. In Minnesota, USA, monitoring for three years prior to and following installation of closed inlets in a large-field on-farm study confirms the reduction in suspended sediment concentrations/loads observed in Indiana. The Minnesota results indicate that SRP concentrations during spring snowmelt are higher than during the remainder of the year and that snowmelt losses are a sizable portion of the annual sediment and SRP budgets. Replacing open inlet tile risers in closed depressions with the blind inlet design studied reduced sediment and phosphorus loads from agricultural closed depressions. The results of this study clearly indicate the consequences of replacing open inlets with blind inlets, information germane to conservation practitioners, policy makers, and researchers.
3. Identifying sources of emerging organic contaminants in a mixed use watershed using principal components analysis. Principal components analysis was used to identify sources of emerging organic contaminants in the Zumbro River watershed in southeastern Minnesota. Two main principal components (PC) were identified. Principal component 1 (PC1) was attributed to non-agricultural land use, including the effects from municipal wastewater and urban/residential land uses, while PC2 was attributed to agricultural land use. The concentrations of cotinine, DEET and the prescription drugs carbamazepine, erythromycin and sulfamethoxazole were best associated with PC1, while the variances of the concentrations of the agricultural pesticides atrazine, metolachlor and acetochlor were most associated with PC2. Mixed use compounds carbaryl, iprodione and daidzein did not specifically group with either PC1 or PC2. Despite the fact that caffeine and acetaminophen are primarily associated with human use, they could not be attributed to a single dominant land use category (e.g., non-agricultural or agricultural). In addition, contributions from septic systems did not clarify the source for these two compounds, suggesting that additional sources, such as runoff from biosolid-amended soils may exist. Based on these results, PCA may be a useful way to broadly categorize the sources of new and previously uncharacterized emerging contaminants or may help to understand transport pathways in a given area. Furthermore, acetaminophen and caffeine are not ideal markers for urban/residential contamination sources in the study area and may need to be reconsidered as such in other areas as well. Improving our understanding of contaminant sources will help focus efforts and resources on strategies to reduce contaminants and sources of contaminants with the greatest risk, improving water quality.
4. Assessing biochar’s ability to reduce bioavailability of aminocyclopyrachlor in soils. This was the first study to assess the use of biochar as a remediation tool for reducing bioavailable aminocyclopyrachlor in the liquid phase soil systems. Aminocyclopyrachlor is a pyrimidine carboxylic acid herbicide used to control broadleaf weeds and brush. Amending soil with activated charcoal is recommended to prevent off-site transport of aminocyclopyrachlor and non-target plant damage. We used the batch-equilibrium method to determine the concentration of aminocyclopyrachlor in a pseudo-steady state with biochar, soil, and biochar-soil systems (<10% biochar by weight). We observed that aminocyclopyrachlor is mobile in soils. Soil incorporation of activated charcoal removed nearly all of the aqueous aminocyclopyrachlor thereby limiting its bioavailability to non-target flora. On the other hand, biochars were less effective than activated charcoal. Biochar produced from olive mill waste feedstock was the most effective biochar that we assessed for reducing the aqueous herbicide concentration. Although these biochars reduced the aminocyclopyrachlor concentration, they would not be practical remediation media due to the extraordinarily high application rates required to reduce the concentration by 50% (2.13×105 kg ha-1 to 7.27×105 kg ha-1). Therefore other remediation strategies should be considered.
Krueger, E., Baker, J.M., Ochsner, T.E., Wente, C.D., Feyereisen, G.W., Reicosky, D.C. 2013. On-farm environmental assessment of corn silage production systems receiving liquid dairy manure. Journal of Soil and Water Conservation. 68(6):438-449.
Wilson, M., Baker, J.M., Allan, D.L. 2013. Factors affecting successful establishment of aerially seeded winter rye. Agronomy Journal. 105(6):1868-1877.
Oliveira, R.S., Alonso, D.G., Koskinen, W.C., Papiernik, S.K. 2013. Comparative sorption, desorption and leaching potential of aminocyclopyrachlor and picloram. Journal of Environmental Science and Health. 48(12):1049-1057.
Marek, L.J., Koskinen, W.C. 2014. Simplified analysis of glyphosate and aminomethylphosphonic acid in water, vegetation, and soil by liquid chromatography-tandem mass spectrometry. Pest Management Science. 70(7):1158-1164.
Celis, R., Adelino, M., Gamiz, B., Hermosin, M., Koskinen, W.C., Cornejo, J. 2014. Nanohybrids of Mg/Al layered double hydroxide and long-chain (C18) unsaturated fatty acid anions: Structure and sorptive properties. Journal of Applied Clay Science. Available at: http://dx.doi.org/10.1016/j.clay.2014.03.026.
Cabrera, A., Cox, L., Spokas, K.A., Hermosin, M.C., Cornejo, J., Koskinen, W.C. 2013. Influence of biochar amendments on the sorption-desorption of aminocyclopyrachlor, bentazone and pyraclostrobin pesticides to an agricultural soil. Science of the Total Environment. 470-471:438-443.
Rittenhouse, J.L., Rice, P.J., Spokas, K.A., Koskinen, W.C. 2014. Assessing biochar's ability to reduce bioavailability of aminocyclopyrachlor in soils. Environmental Pollution. 189:92-97.
Oliveira, R.S., Koskinen, W.C., Graff, C.D., Anderson, J.L., Mulla, D.J., Nater, E.A. 2013. Acetochlor persistence in surface and subsurface soil samples. Water Air And Soil Pollution. DOI: 10.1007/s11270-013-1747-2.
Xie, T., Reddy, K.R., Wang, C., Yargicoglu, E., Spokas, K.A. 2014. Characteristics and applications of biochar for environmental remediation: A review. Critical Reviews in Environmental Science Technology. DOI: 10.1080/10643389.2014.924180.
Hall, K.E., Calderon, M.J., Spokas, K.A., Cox, L., Koskinen, W.C., Novak, J.M., Cantrell, K.B. 2014. Phenolic acid sorption to biochars from mixtures of feedstock materials. Water, Air, and Soil Pollution. 225:1-9.
Spokas, K.A., Novak, J.M., Masiello, C.A., Johnson, M., Colosky, E., Ippolito, J.A., Trigo, C. 2014. Physical disintegration of biochar: An overlooked process. Journal of Environmental Science and Technology. 1(8):326-332.
Heilmann, S.M., Molde, J.S., Timler, J.G., Wood, B.M., Mikula, A., Vozhdayev, G.V., Spokas, K.A., Colosky, E., Valentas, K.J. 2014. Phosphorus reclamation through hydrothermal carbonization of animal manures. Journal of Environmental Science and Technology. 48(17):10323-10329.