A comparison of a short-rotation willow and grass biofuel crops to grain crops on marginal, claypan soils was conducted. Willow establishment failed as a result of the extreme heat/drought conditions of 2011 and 2012, and was replaced with miscanthus. Miscanathus establishment was good regardless of landscape position, rhizomes > 18 g produced more biomass, and nitrogen fertilization did not generally improve first- or second-year yield. Switchgrass yield in 2013 and 2014 ranged from five to six tons/acre; comparable with similar claypan studies. Baseline soil and water quality has been obtained, with instrumentation upgrades to aid future studies.
Marginal soils, like many claypan and claypan-like soil areas of the North Central Region, are disproportionate sources for non-point pollution and soil quality degradation when used for grain production. In the North Central Region, these two Major Land Resource Areas occupy over 11 million acres and are generally defined as being highly erodible and having average to poor grain crop yield. The high erosion rates of these soils have caused many field areas to lose 30 to 90 percent of their topsoil as a result of cultivation practices over the last 150 years. These marginal soils from a grain production standpoint also contribute the most to environmental concerns, such as additional erosion and nutrient losses from fields. Alternative production systems are needed for long-term productivity and environmental sustainability. Woody biomass plantations could help address those concerns.
The resulting fiber from woody biomass plantations could also be a feedstock source for emerging bioenergy markets. For example, in 2013 the University of Missouri’s (MU) Energy Plant installed a biomass boiler creating a market for 100,000 green tons of wood chips annually. While the initial plan calls for the energy plant to utilize sawmill residues, MU is interested in developing long-term supply contracts with farmers capable of growing dedicated wood energy crops to offset reduced mill residues during a poor economy. This demand for biomass created an opportunity to: (1) evaluate the potential positive effects that woody energy crops can have on improving soil and water quality, and soil structure on marginal upland sites, and (2) demonstrate the potential these energy crops have for improving farm profitability.
The woody energy crop initially proposed in this research was short-rotation willow. Establishment of the willow on claypan soil research site was greatly frustrated by the extreme heat and drought summers experienced during the first two years of this study (2011 and 2012). After extensive discussions, the consensus of the research team was the droughty nature of upland claypan soils would make it extremely difficult to establish a viable short-rotation willow biofuel cropping system. Input from the farmer Advisory Board supported this conclusion. Given this conclusion, alternative bioenergy crops were considered and miscanthus was selected as a replacement. Miscanthus was chosen primarily because some of the first production acres in the US were planted in the Central Missouri region in the spring of 2012 as a part of the USDA BCAP project. USDA NRCS supported miscanthus as the replacement crop for this study because very little was known about miscanthus production and impact on water use, runoff and water quality, and soil health. After consultation with North Central Region SARE program staff, a formal request altering the willow energy crop to miscanthus was made and approved in the spring of 2013.
The agriculture industry is faced with increasing demands for food, feed, and energy, dwindling available resources in energy and land, and increasing productivity uncertainty due to climatic variability. We propose to address these challenges for marginal Midwest soils, where grain cropping over the past 150 years has accelerated erosion and severely degraded cropland productivity (Lerch et al., 2007; Massey et al., 2008). With the prospect of emerging bioenergy feedstock crops, degraded soil landscapes will likely be prime candidates for perennial bioenergy feedstock crop production that would allow for restoration of ecosystem services. A review of the SARE database revealed no similar projects designed to address the problem stated in our proposal.
Marginal Claypan Soils
The Midwestern U.S. claypan region encompasses an area of about 10 million acres within Missouri, Illinois, and Kansas (Jamison et al., 1968; Anderson et al., 1990). In Missouri, claypan soils are predominant in the North-East quadrant of the state and are the major soils of the Salt River Basin feeding into the Mark Twain Reservoir. These soils are characterized by a subsoil horizon with an abrupt and large increase in clay content compared to the overlying materials occurring within a short vertical distance in the soil profile (Soil Science Society of America, 2001). The claypan occurs at depths varying from 0.3 to 1.6 ft with clay content ranging from 35 to 65% (Miles and Hammer, 1989; Blanco-Canqui et al., 2002; USDA-NRCS, 2006). Claypan soils are usually classified as somewhat poorly to poorly drained and have slow to very slow permeability. The low saturated hydraulic conductivity of the claypan perches water creating a high probability of runoff in most years during the winter and spring periods (Blanco-Canqui et al., 2002) and during wetter-than-average summer growing seasons.
Plant-Available Water and Claypan Soil Production
Crop growth in response to soil available water as affected by cropping systems can be difficult to characterize because of highly variable soil and landscape properties, such as surface run-on and run-off, subsurface water redistribution, soil horizon distributions, and organic matter. Particularly problematic are the claypan soils since profile water storage is generally low, limiting crop production in most average to dry precipitation years. Water storage is especially reduced in eroded areas with shallow topsoil (Jiang et al., 2008). In consequence, this property of topsoil depth is a dominant factor in grain yield variability within fields (Kitchen et al., 2005). High clay content at or near the soil surface of these soils also limits grain yield due to poor germination, reduced infiltration, and poor soil moisture recharge. Yield within these fields often varies as much as 4:1 from high- to low-yielding areas.
In the last 15 years grain yield monitoring, which records grain yield point-by-point during field harvesting, has revolutionized farmers’ ability to quantify field productivity. Along with helping to understand specific management decisions (e.g., variety, variable fertilizer application), yield monitoring has elucidated the impact of landscape properties (Fraisse et al., 2001; Kravchenko and Bullock, 2000) and the lost productivity with eroded topsoil (Kitchen et al., 1998). Initial work using yield maps from Northeast Missouri showed that the acres of economically marginal soils currently in grain production may be larger than previously thought (Massey et al., 2005), because profitability has traditionally been calculated on a whole field or whole farm basis. One exercise from this study took 10 years of corn and soybean yield maps from an 88 acre claypan soil field and converted them to profitability maps. They found that on average 25 percent of the field cost more to farm than the grain revenue generated from those areas. Their conclusion was less risky crop production systems are needed for such claypan soil fields.
Landscape Linkages between Productivity and Ecosystem Function
Farmers want to be good stewards of the land they manage (Murphy et al., 2010). However, given the economic constraints they are subjected to, it often takes personal observation to trigger a change in practices (Murphy et al., 2010, Wright-Morton et al., 2007). Thus, where there is evidence of degradation that decreases productivity, e.g. erosion rills or frequent flooding from a nearby stream, practices are put in place to remedy the problem. These practices are subsidized by USDA because they also improve environmental stewardship and thus benefit everyone. In some areas, erosion control measures will be implemented, in others riparian buffers will be established. However, when the problem is gradual (i.e., due to 100 years of cultivation) and invisible (e.g., soil degradation, chemical runoff), there is no visual evidence and thus no likely remedy undertaken.
Research investigating the links between ecosystem function and productivity is limited. Perhaps the most relevant work is from Mudgal (2010) who used the APEX model to show that, if the backslope portions of a claypan soil field still had original soil properties (i.e. as they were before agricultural production for 100 years caused soil degradation), runoff and atrazine loss from these areas would be significantly lower and corn and soybean yields would be significantly higher.
Cellulosic Biofuel Crops as an Alternative to Grain Cropping
Because grain yield on marginal claypan soils is vulnerable to both drought (average to dry years) and excess wetness (wet years) due to the presence of this heavy-clay subsoil, risk is high with regard to grain crop profitability. For this reason, marginally productive soils in this region are prime candidates for conversion from grain crops to grass production for biomass energy and soil and water conservation. Upland claypan soils in Northeastern Missouri are well suited for perennial plants such as willows and warm season grasses. Prior to settlement, these areas supported water-use-efficient native warm season grasses and some woody species in localized upland locations and along streams and rivers (Lerch et al., 2007). Perennial grasses such as those used for biofuel crops often improve physical soil properties (e.g., bulk density, water infiltration, aggregate stability) compared to annual crops such as corn or soybean (Jiang et al., 2007; Blanquo-Canqui, 2010). In addition, the water demand from biofuel crops is higher earlier in the season and chemical inputs are lower than for grain crops, thus potentially delaying generation of runoff and soil erosion, and reducing pollutant transport (Schilling et al., 2008). Consequently, it is likely that introducing perennial bioenergy crops in the agricultural landscape would lead to improved water quality. Preliminary results confirmed this trend for small field size watersheds in Iowa (Liebman et al., 2010). Researchers using the APEX model showed that planting perennial grasses on the backslope of a 35 ha field reduced sediment and nutrient loadings (Mudgal, 2010).
Integration of modern bioenergy production into current cropping systems presents new soil management challenges, and opportunities. Our current limited knowledge of production demands of biofuel crops is inadequate to predict the ecological impacts of these crops on soil processes. Bioenergy production is now beginning to involve cellulosic biofuels in addition to grain bioethanol/biodiesel (Blum et al., 2010). Regardless of which bioenergy system is used, guidelines for BMPs will be necessary to sustain or improve soil quality and acceptable soil productivity (Blanco-Canqui, 2010; Johnson et al., 2007; Wilhelm et al., 2004). Biomass harvest has potential to impact soil nutrient dynamics, water relations, and other important soil processes. The strong linkage of above-ground and below-ground biodiversity (Wardle, 1995; Grayston et al., 1998) suggests that mixed perennial grasses and fast-growing woody species managed for biofuel production may be more beneficial than annual crop monocultures for maintaining diversity of soil microorganisms and overall soil quality, and may also be more resilient to climate change than grain crops because of perennialization.
Very little research on soil quality in the context of biofuel production has been conducted (Blanco-Canqui, 2010). Existing information focuses primarily on the response of soil organic C, considered the key soil quality indicator (Johnson et al., 2006), to residue management in annual crops and to growth of perennial crops in undisturbed soils. Soil C under switchgrass as a biofuel crop increased by 10 Mg ha-1 yr-1 within a 3 ft soil depth in temperate climates (Garten and Wullschleger, 1999). Current research at USDA-ARS, Mandan, ND demonstrated variable changes in soil C under switchgrass five years after establishment (Liebig et al., 2008). Even less is known about effects of woody biofuel species other than increased soil C accumulation and N mineralization under short rotation coppice plantations of willow compared with cultivated fields (Blum et al., 2010; Jug et al., 1999). However, conversion of grassland to short-rotation forestry plantations tends to accelerate initial soil C and N losses before recovering to original or increased levels after trees become established (Jug et al., 1999).
Woody Biomass Systems
Woody crops have advantages as a feedstock for bioenergy. Generally, the woody material is a consistent energy source (Miles et al., 1996) and has low mineral ash. They have the advantage of flexibility in harvest times that grain crops do not have. Production inputs (e.g., fertilizers and herbicides) for managing the woody crops are much reduced from what is necessary for grain crops. Finally, woody biomass net energy ratios are greater than many other feedstocks for biofuels, usually in the 10-20:1 range (Keolian and Volk, 2005), thus considerably more energy is produced per unit fossil fuel used from woody feedstock crops. This net energy ratio will become an increasingly significant factor as advanced liquid fuel production technologies mature. Shrub willow (Salix spp.) crops are an example of a production system that has shown promise as a biomass crop in the United States in recent decades (Volk et al., 2006). It has been grown successfully on marginal agricultural lands in much of the eastern half of the U.S. (Appendix 9). Trials have demonstrated yields of three to five tons per year for the first rotation (Volk and Luzadis 2009), and 20 to 50 percent more than that for secondary rotations. Recent studies at the University of Minnesota (Thelemann et al, 2010) have indicated that landscape position may affect the productivity of willow, cottonwood (Populus deltoides), and hybrid poplar (Populus maximowiczii x P. nigra), suggesting that further research needs to be conducted.
Energy Balance of Perennials
Perennial woody species and grasses for biomass energy are desirable over grain-based biofuels since the latter have been projected to be a net producer of greenhouse gasses (Lewandowshi et al, 2003). The carbon balance of biofuel production on marginal soils is less compared to high yielding soils. In contrast to biofuel production, perennial grasses sequester atmospheric carbon due to their extensive perennial root systems. The energy balance of ethanol and biodiesel production is also less positive for marginal soils than for prime farmland. A similar amount of equipment, fuel and chemicals are used on both, while the yield of grain is depressed on marginal soils. It follows that using marginal soils for grain biofuel production may result in a loss of energy (or net negative energy) because of depressed yields when growing conditions are not ideal. However, the energy balance of warm season grass biomass production is several times more positive than that of grain (Tilman et al., 2006). Thus, for the goals of maximizing energy production and sequestering carbon, biomass is a better solution on marginal soils.
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Fraisse, C.W., K.A. Sudduth, and N.R. Kitchen. 2001. Delineation of site-specific management zones by unsupervised classification of topographic attributes and soil electrical conductivity. Trans. ASAE 44(1):155-166.
Garten, C. T. and S.D. Wullschleger. 1999. Soil carbon inventories under a bioenergy crop (switchgrass): measurement limitations. J. Environ. Qual. 28:1359–1365.
Ghidey, F., Blanchard, P.E., Lerch, R.N., Kitchen, N.R., Alberts, E.E., Sadler, E.J. Measurement and prediction of herbicide transport from the corn phase of three cropping systems. J. Soil Water Cons. 60(5): 260 273. 2005.
Grayston, S.J., S.Q. Wang, C.D. Campbell, and A.C. Edwards. 1998. Selective influence of plant species on microbial diversity in the rhizosphere. Soil Biol. Biochem. 30:369-378.
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Jiang, P., Anderson, S.H., Kitchen, N.R., Sudduth, K.A., Sadler, E.J. 2007. Estimating plant-available water capacity for claypan landscapes using apparent electrical conductivity. Soil Science Society of America Journal. 71:1902-1908.
Jiang, P., Kitchen, N.R., Anderson, S.H., Sudduth, K.A., Sadler, E.J. 2008. Estimating plant-available water using the simple inverse yield model for claypan landscapes. Agronomy Journal. 100:830-836.
Jiang, P., S.H. Anderson, N.R. Kitchen, E.J. Sadler, and K.A. Sudduth. 2007. Landscape and conservation management effects on hydraulic properties of a claypan-soil toposequence. Soil Sci. Soc. Am. J. 71(3): 803-811.
Johnson J.M.F., R.R. Allmaras, and D.C. Reicosky. 2006. Estimating source carbon from crop residues, roots and rhizodeposits using the national grain-yield database. Agron. J. 98:622-636.
Johnson, J.M.F., M.D. Coleman, R. Gesch, A. Jaradat, R. Mitchell, D. Reicosky, W. W. Wilhelm. 2007. Biomass-bioenergy crops in the United States: A changing paradigm. Am. J. Plant Sci. Biotechnol. 1:1-28.
Jug, A., Makeschin, F., Rehfuess, K.E., and C. Hofmann-Schielle. 1999. Short-rotation plantations of balsam poplars, aspen and willows on former arable land in the Federal Republic of Germany. III. Soil ecological effects. For. Ecol. Manage. 121:85-99.
Keoleian, G.A. and T.A. Volk. 2005. Renewable energy from willow biomass crops: life cycle energy, environmental and economic performance. Critical Reviews in Plant Science, 24: 385-9 406.
Kitchen, N. R., K.A. Sudduth, D.B. Myers, R.E. Massey, E.J. Sadler, R.N. Lerch, J.W. Hummel, and H.L. Palm. 2005. Development of a conservation-oriented precision agriculture system: Crop production assessment and plan implementation. J. Soil Water Cons. 60(6): 421-430.
Kitchen, N.R., K.A. Sudduth, and S.T. Drummond. 1998. An evaluation of methods for determining site-specific management zones. p.133-139. In Proc. North Central Extension-Industry Soil Fertility Conf., St. Louis, MO, Nov. 11-12, 1998.
Lerch, R.N., E.J. Sadler, N.R. Kitchen, K.A. Sudduth, R.J. Kremer, D.B. Myers, C Baffaut, S.H. Anderson, , and C.H. Lin. 2007. Overview of the Mark Twain Lake/Salt River Basin conservation effects assessment project J. Soil Water Cons. 63(6):345-359.
Lewandowski, I., Scurlock, J.M.O. Lindvall, E. and Christou, M. 2003. The development and current status of perennial rhizomatous grasses as energy crops in the US and Europe. Biomass and Bioenergy. 25: 335-361.
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Massey, R.E., Myers, D.B., Kitchen, N.R., and Sudduth, K.A. Profitability maps as input for site-specific management decision making. Agron. J. 100:52-59. 2008.
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Objectives / Performance Targets
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The overarching objectives of this project were to: (1) evaluate the potential positive effects that woody energy crops (later miscanthus) could have on improving soil and water quality, and soil structure on marginal upland sites, and (2) demonstrate the potential these energy crops have for improving farm profitability. As such the project sought to simultaneously demonstrate that farmers could improve crop profitability and soil and water quality by replacing under-performing grain crops growing on marginal cropland with better-performing, low-input, grass and short-rotation woody (or miscanthus) biomass plantings. The project took an integrated approach to dedicated energy crop development combining environmental and production research with outreach efforts designed for both farmers and educators. The goal was to afford farmers and educators the opportunity to observe all phases of producing energy crops (e.g. establishment, growth and development, and harvesting), as well as comparing production inputs/outputs to conventional grain cropping systems. More importantly, soil and water data from the replicated plots would enable researchers to assess the environmental sustainability of growing dedicated energy crops. The project was viewed to be long-term in nature with this SARE R&E Grant providing the initial funding. It was hoped these findings would lead to additional competitive funding.
Expected outputs: (1) two, peer-reviewed manuscripts evaluating quantitative yield data and/or nutrient, herbicide, sediment, and runoff volume among the cropping systems; (2) project press releases through newsletters, local newspapers, and eXtension; (3) MU Guide Sheets on growing willow or miscanthus for bioenergy; and (3) fall workshops, one at the end of each year of the project, for educators (Extension, NRCS, MO Department of Conservation, high school agricultural education instructors, etc) and farmers.
Upon attending a workshop, the educator was to share their knowledge with farmers and other agricultural educators in their region. This could have been through face-to-face workshops or distance-learning webinars. The expectation was for a minimum of ten farmers or agricultural educators to attend each event offered. Upon attending a workshop, at least six Mid-Missouri farmers within 50 miles of an established bioenergy facility would begin establishing dedicated energy crops.
Short-term outcomes: (1) Farmers and educators would increase their knowledge of the soil-enhancing benefits of producing dedicated energy crops on marginal claypan soils; (2) Farmers and educators would learn how to produce these crops.
Intermediate outcomes: (1) Early-adopter farmers would use the information they learned to establish sustainable supplies of biomass to support established bioenergy markets in mid-Missouri, such as the University of Missouri Energy Plant in Columbia and Show-Me Energy in Centerview, Missouri; (2) The less intensive management in producing energy crops compared to conventional grain cropping systems would reduce soil erosion; and (3) Educators would disseminate their expanded knowledge of producing dedicated energy crops in their region of influence.
Long-term outcomes: (3) Farmers growing energy crops on marginal claypan soils would reduce their production input costs compared to conventional grain cropping systems thereby increasing their profitability; (2) Soil organic matter and soil structure would be improved over time as a result of leaving plant root systems in the soil; and (3) The expanded growth and development of the supply chain involved in producing, harvesting, and transporting bioenergy crops to bioenergy facilities would provide stable jobs and enhance the quality of life in rural communities.
The Agricultural Research Service’s Cropping Systems and Water Quality Research Unit based in Columbia, MO has a long-term cooperative agreement on a farm located one mile north of Centralia, Missouri (39?13 N, 92?07 W) in Major Land Resource Area (MLRA) 113, the Central Claypan Region (USDA-NRCS, 2000). The site is called the Centralia Research Center (CRC) and has an average annual precipitation at this site is 39 inches. Initiated in 1991, the site over the years has been well characterized with topography, soil survey (order-one), soil sampling, and sensor-based soil properties (e.g., topsoil depth).
The CRC has an area divided into 30 plots; each plot measures 60 feet x 620 feet for a total of 0.85 acres and includes a soil landscape of summit, backslope, and footslope positions. Thus, interactions of management and landscape variability can be examined. The summit landscape position was mapped as Adco (fine, smectitic, mesic Vertic Albaqualf) silt loam with 0-1percent slopes; the backslope position was mapped as Mexico (fine, smectitic, mesic Aeric Vertic Epiaqualfs) clay loam with 1-3 percent slopes; and the footslope LP was mapped as Mexico silt loam with 1-2 percent slopes. These three soils are very similar and differ only by subtle differences in diagnostic features. The soils are deep, somewhat poorly drained, and very slowly permeable, because of the restrictive high-clay subsoil layer (the “claypan”) which contains approximately 60 percent clay at this site. The landscape is linear to slightly convex at the summit position and linear to slightly concave in the backslope and footslope LP. The difference in elevation between summit and footslope positions is about 10 feet.
Prior to the research represented by this proposal, primary cropping systems evaluated were corn, soybean, and wheat crops, with either conventional or no-tillage practices. With this study some plots were converted to perennial bioenergy cropping systems. Side-by-side comparisons of grain and biofuel cropping systems across a soil landscape were a unique feature of this study.
Three replicates of five cropping systems were evaluated: (1) mulch-till corn and no-till soybean system, comparable to what many farmers use in this region; (2) no-till corn-soybean with a switchgrass bioenergy crop replacing grain cropping on the 25 percent of each plot that is most vulnerable to generating runoff and erosion; (3) no-till corn-soybean-wheat with cover crops used after both corn and soybean crops; (4) switchgrass bioenergy crop; and (5) short-rotation willow bioenergy crop (changed to miscanthus in 2013). Implementation details of the cropping systems were recently published (Yost et al., 2015).
The mulch-till corn and no-till soybean system is similar to a cropping systems studied since 1991 and thus provided a bridge between the research eras at the proposed study site. The no-till corn-soybean with a switchgrass energy crop is a mixed grain-grass system that represents a form of landscape targeting, relying on a perennial crop to both improve production stability and ecosystem services in localized areas to achieve field-level sustainability goals. The no-till corn-soybean-wheat with cover crops after both corn and soybean is a system continued from previous research.
Yield (grain or harvestable biomass), grain or biomass quality (N, P, K, micronutrients), forage quality (ADF, NDF, IVDMD), energy components (percent lignin, ethanol yield, sugar profile, C content), and soil quality indicators (soil organic matter, total N, aggregation, and microbial activity were to be evaluated by cropping systems and by landscape position (summit, backslope, footslope). A split-plot (yield) or split-split-plot (soil quality) experimental design treatment arrangement was used with cropping systems as the main plot, landscape position as the split-plot, and soil depth as the split-split plot (soil quality only). Because landscape position and depth are not randomized, a repeated-measures analysis (Littell et al., 2002) was proposed to assess the response variables using PROC MIXED in SAS. Significant interaction effects were to be analyzed using the SLICE option within the LSMEANS procedure.
Water quality was assessed by plot. In 1991 when plots were developed, berms (1 feet high x 5 feet wide) running down slope were created along the plot length to ensure no cross-plot contamination of surface runoff. To eliminate subsurface movement in lateral interflow between plots, a one-meter deep trench on plot borders was dug, lined with heavy plastic, and backfilled. Over the period of 2012-2014, and with the help of this grant,18 of the 30 plots were re-instrumented with flumes and automatic samplers to measure runoff volume and collect runoff samples for chemical and sediment analysis. Wing walls were constructed at the lower end of each plot to route runoff through the flume. Samplers were installed, calibrated, and serviced according to manufacturer guidelines. However, results were inconsistent in the first couple of years, because of equipment failure and lack of sensor protection during winter months. Thus flume and sensor modifications were required in order to create sampling units that would give sensitivity to sampling needed for these plots and to enable reliable sampling year-long (Sudduth et al., 2015). Nutrients, herbicide, sediment, and runoff volume were assessed for each precipitation event producing runoff, following modified procedures previously developed for this same research site (Ghidey et al., 2005).
In addition, grain and bioenergy cropping systems were to be evaluated under climate change scenarios, which are characterized by increasing variability of extreme weather, i.e., increasing rainfall and rainfall intensity, as well as increasing magnitude and frequency of droughts. Currently, this can only be done using modeling. The APEX models previously calibrated for this site were proposed to be used but adjusted to reflect the changes in management for some of the plots. Climate change scenarios were to be obtained from regional downscaled information. Interactions among the various weather variables (precipitation, temperature, relative humidity, solar radiation, and wind speed) will be explored to obtain coherent climate scenarios. The APEX model was to be run on each plot for 30-year series of current and future weather. Output variables obtained with the two weather series, i.e., crop yields and environmental variables, will be tested for significant differences.
Education and Outreach Methods
The above research results were to be disseminated through (1) peer-reviewed publications in appropriate scientific journals, and (2) various university Extension platforms. Information released through print media (e.g. newsletters and newspapers) was documented as to the number articles written, to whom they were released and their circulation. Information released through electronic media (e.g. webinars and eXtension’s Community of Practice) was to be documented by tracking the number of distinct URL’s visiting the website, length of stay, and document downloads. For information released through the annual workshops, participants were to be given pre- and post-workshop surveys to determine knowledge gain and gauge reaction the training (content and delivery) and intent on adopting the practice(s). Six-month follow-up surveys were to be sent to producers to document how many of them who have begun planting either switchgrass, willow, or miscanthus as an energy crop and the number of acres planted. Educators attending the workshops were asked to report the number of articles they wrote for local and regional newspapers, the number of new workshops they conducted specifically related to energy crops, inclusion of knowledge gained into existing programming, back in their home territory and the number of farmers attending.
Results below include both research directly funded through this SARE grant, as well as other research that indirectly helps address the stated objectives of the SARE grant project. Research that have indirectly supported this projects objectives are marked with an asterisk (*).
Willow at the Centralia Research Center
In 2012, Missouri experienced a prolonged, extreme drought throughout the entire growing season. The drought was coupled with extreme temperatures. These extreme weather conditions resulted in a complete failure of the woody biomass plantings at the Centralia Research Center (CRC). At the same time the demand for woody biomass at the University of Missouri was being met through an ample supply of sawmill residues. That oversupply coupled with low prices for woody biomass effectively eliminated producer interest. At the same time, miscanthus was being established throughout the region by a private commercial entity and producer interest in this energy crop was high. With no additional resources to re-establish the willow plantings in 2013 and producer interest in miscanthus rising, the research team decided to replace the willow plots with miscanthus. The team notified the SARE coordinator of this project redirection and at the same time requested a one-year no-cost extension. Both requests were approved.
The greatest limitation of using willows on the claypan soil landscapes was the difficulty in establishing the willow energy crop. Standard procedures call for willow to be established in the early spring by placing stem cuttings in the ground using special, mechanized equipment. Only researchers at the State University of New York (SUNY) and the University of Minnesota have these specialized planters. Changing weather conditions, distance between us and these potential cooperators, and the priority those cooperators would give their projects over ours would have meant difficulty aligning resources to establish the study under dry conditions. Further, using mechanized equipment in saturated field conditions ran the risk of creating artificial runoff channels (i.e. ruts) that would skew soil and water quality data. While establishing the crop by hand could call into question the applicability of our findings, a farmer would normally not establish the crop under saturated field conditions. So, soil and water data were assumed to be applicable.
Another limitation was the project being conducted at only one location. Collecting valid runoff and water quality data, the test plots required trenches to eliminate lateral subsurface water flow between the plots, constructing the flumes at the bottom of each plot’s footslope, and instrumenting each flume with automatic samplers to measure runoff volume and collect runoff samples for chemical and sediment analysis. The Columbia-based USDA Agricultural Research Service’s Cropping Systems and Water Quality Research Unit’s research farm was designed to collect such data and the time and expense to construct a similar facility at another location was beyond the scope and funding of the proposed study.
While we did expect to see significant genotype-by-environmental interaction, we did not expect to experience catastrophic failure of willow due to its widespread distribution in nature. The highest probability for soil erosion within a woody energy cropping system was within the first year after establishment as the trees develop their root systems. But, once established the extensive root system should have increasingly stabilized the soil over time as only the shoots are harvested every three years. Production inputs were also expected to be lower because the crop is fertilized every three years, and tillage or herbicide applications are not needed after the first year. Unfortunately we were never able to get past the establishment stage to verify these hypotheses.
Given the project modifications with a focus on miscanthus, expected outputs were: (1) successful establishment of the miscanthus plots, (2) collection and analyses of runoff and water quality data from all plots, (3) provide project information through traditional media as well as eXtension, and (4) host a fall workshop on establishing energy crops.
Miscanthus at the Centralia Research Center
Establishment of miscanthus on the CRC has also been challenging. In the late fall of 2012 the few willows that survived the drought of 2012 were removed and the ground prepared for miscanthus planting. A cover crop of cereal rye was broadcast seeded to minimize winter and early-spring erosion. The cereal rye was sprayed with glyphostate 10 days before miscanthus planting. Miscanthus planting was timely and in favorable soil conditions. However, after 6 weeks very little miscanthus had emergence. It was concluded something was inhibiting the miscanthus. Causes explored included rhizome quality, planting depth, and herbicide carry-over. In the end, the likely problem attributed to the stunted miscanthus was allelopathy associated the cereal rye cover crop. Numerous cases of cereal rye allelopathy impacting corn growth on cool wet soils have been documented, but nothing in the literature has documented a similar effect on miscanthus. While no direct measurements were taken, it was noted with visual observations that the best miscanthus emergence and growth occurred where cereal rye was weakest. Attempts to replant in late-June with new rhizomes failed too, in part because the new batch of rhizomes were green, that is they were harvested after breaking dormancy. Green rhizomes would have less energy reserve to support emergence and initial vegetative growth.
Miscanthus replanting in 2014 resulted in near fully-stocked plots. Unfortunately the winter of 2014-15 had an extended period with no snow and sub-zero conditions and the newly established plants were greatly stressed. Reassessment in the spring of 2015 found about 50% of the plants did not survive the winter, and additional hand-planting was immediately done to fill-in where plants had winter-killed.
Normally first harvest of miscanthus would be possible the year after planting. However, with the allelopathy and winter kill issues experiences at the CRC, no meaningful biomass harvesting has been possible during the period of this project. We anticipate miscanthus harvest after the 2016 growing season.
One positive result of incorporating miscanthus into this project was the addition of two key studies that were conducted to supplement the CRC research: (1) determine miscanthus yield response to nitrogen (N) fertilizer for marginal claypan soils in order to determine N fertilizer application rates; and (2) quantify the impact of rhizome quality and depth to the claypan horizon on miscanthus emergence and early growth. There findings follow.
Nitrogen Needs for Miscanthus
The objective of the nitrogen (N) study was to assess miscanthus N needs on claypan soils. The N study was conducted as two different experiments.
The first is an N rate experiment initiated on a mature miscanthus stand grown on a claypan soil site at the Jefferson Farm, adjacent to the University of Missouri South Farm (located near Columbia). For this study, a block of miscanthus was planted in 2007 with plots overlaid for N rate treatments in 2012. A randomized complete block design was used to further divide the area into three main blocks (i.e., reps), each block was then divided into four separate main plots of 3.7 x 13.7 m dimensions. Treatments of 0, 40, 80 and 120 lbs N/ac. were hand applied once in 2012 shortly after green-up (around May). No additional N fertilizer was applied because N build-up in the soil and miscanthus rhizome was thought sufficient to sustain this year’s growth while still providing treatment difference from N fertilizer but down in 2012. SPAD chlorophyll readings were taken at four-week intervals throughout the growing season (June, July, August, and September). In mid-December each plot was harvested individually to determine yield quantities. A 1.4 m sickle mower was used to cut against the rows removing approximately 0.7 m on the ends of each plot to form a buffer row. One 1.4 m swath with the sickle mower then cut down the center of the plot forming an average harvestable plot area of 16.7m2. The canes from each plot were bundled and weighed using a scale attached to the bucket of a tractor and elevated as to leave the bundled biomass in unaided suspension while a weight was recoded. Subsamples were taken to determine moisture and nutrient content.
The second experiment was also an N rate experiment conducted over the 2012-2015 growing seasons at The University of Missouri South Farm (Mexico silt loam), and two producer fields, one in Cooper County (Weller silt loam) and one in Moniteau County (Menfro silt loam). Each of these sites were selected because they represent the unique characteristics of claypan soils, which as discussed earlier exhibit a pronounced enriched-clay soil horizon, which is restrictive to root growth and grain production and in turn impacts grain yield negatively when topsoil overtop this claypan is eroded.
Each of these sites had existing one-year-old miscanthus stands and were organized using a randomized complete block design with four main blocks divided into six separate plots. Plot dimensions varied between locations and were as follows: South Farm, 3.8 m x 9.1 m; Cooper and Moniteau County, 3 m x 4 m. Treatments of 0, 30, 60 and 120 lbs N/ac. were applied shortly after green-up in early May (Photo 1). Similarly to Jefferson Farm SPAD chlorophyll readings were taken at four-week intervals throughout the growing season (June, July, August, and September).
Early season measurements of chlorophyll content using SPAD readings were found to be impacted by N rates (Figure 1). However, as the season progressed, N rate treatments diminished. These chlorophyll results matched our findings from 2013.
In mid-December of 2013 and 2014 the plots were harvested to determine yield quantities. A 1.4 m sickle mower was used to cut against the rows removing approximately 0.7 m on the ends of each plot to form a buffer row (Photos 2 and 3). One 54 in. swath with the sickle mower then cut down the center of the plot forming an average harvestable plot area of 9.9m2, 3.5m2, and 3.9m2 for Lone Tree, Cooper County, and Moniteau County, respectively. The canes from each plot were bundled and weighed using a scale fixed to the center of a pole and then elevated by two people as to leave the bundled biomass in unaided suspension while a weight was recoded. Subsamples were taken to determine moisture and nutrient content.
Miscanthus yield was not increased by higher N fertilizer rates (Figure 2) for all location except for Boone County (LT). These results matched our finding from 2013. This could be due in part to the perennial nutrients that were recycled from last year’s growth, which supplied adequate nutrients even for those treatments with no N.
The decision was made to run the study one more growing season (2015) before completing the analysis and writing the results for a journal manuscript. To date, with the eight site-years from over two growing seasons (2013-2014), miscanthus yield was only benefitted by N fertilization at one site, with an increase of 3.3 tons/ acre over unfertilized plots. For most sites, in-season measurements of chlorophyll content is different by N rate, but this most often doesn’t translate into a yield difference.
Miscanthus Rhizome Quality Impacts on Establishment
The objective of the rhizome quality study was to quantify the impact of rhizome quality and depth to the claypan horizon on miscanthus emergence and early growth. The first year of this study was conducted at the University of Missouri South Farm located near Columbia. Rhizome quality was characterized by measuring the mass, total length (found by summing the lengths of all protruding parts), diameter, and number of active buds. In order to insure accuracy of measurements each rhizome was rinsed in water to cleanse it of soil and debris. Rhizomes were selected at random from the population. Priority was given to healthier looking rhizomes for both characterized rhizomes and those that were not part of the study, which essentially act as controls.
The first week following planting, characterized rhizomes were visited every other day to record new shoot emergence. Visits to the site were lengthened to two weeks and then monthly intervals as new shoot emergence slowed. Yield data were obtained for each characterized plant at the end of the growing season. Basal circumference was also taken prior to harvest. Weekly soil temperature and seasonally soil moisture measurements were also taken during the initial months following planting.
The following graphs provide some preliminary findings of how biomass production related with the quality of miscanthus rhizome (Figure 3). In general, initial growth and establishment was impacted little by rhizome quality or depth to the claypan.
Due to the inability to repeat this study in 2014 at the Columbia location, the second year of the study was conducted at the CRC on the plots previously occupied by the willow trees. This study was incorporated into the 2014 replanting mentioned previously. Three plots (one from each block) were used for this experiment.
Rhizomes were characterized as before, planted, and had measurements taken on them as described for SPARC previously. Three randomly spaced subplots for each landscape position (27 total subplots) within a plot had four characterized rhizomes (108 rhizomes total). The rhizomes were spaced at 76 cm in a quadrat, planted to a depth of 10 cm and flagged (Photo 4). Measurements were the same as those made at the Columbia location.
Rhizome quality was characterized by measuring the mass, total length (found by summing the lengths of all protruding parts), diameter, and number of active buds. In order to insure accuracy of measurements each rhizome was rinsed in water to cleanse it of soil and debris. Rhizomes were selected at random from the population.
The first week following planting, characterized rhizomes were visited every other day to record new shoot emergence (Photo 5). Visits to the site were lengthened to two weeks and then monthly intervals as new shoot emergence slowed. Yield data were obtained for each characterized plant at the end of the growing season. Basal circumference was also taken prior to harvest. Weekly soil temperature and seasonally soil moisture measurements were also taken during the initial months following planting. In the spring of 2015 mortality rates among the characterized plants were determined.
The second year of the rhizome quality study had 83% establishment rates of newly planted miscanthus rhizomes. A general trend of rhizomes with a larger length, mass, and diameter performed better as indicated by end-of-season, plant basal circumference and the numbers of tillers they produced (Photo 6). Early in the season DTC and viable bud count was important for developing into new tillers, but the effect of these properties faded as the growing season progressed. Rhizomes were shown to perform best in the most eroded parts of the landscape at both locations. Though this phenomenon is difficult to explain, it is encouraging that M. x giganteus is not sensitive to these highly vulnerable and degraded portions of the landscape for establishment.
Research found establishment of miscanthus rhizomes generally performed best on the more eroded parts of the landscape. Further, miscanthus rhizomes that were longer and/or had greater mass had the most positive effect on first-year establishment and growth. The results initially reported in an MS thesis, “Establishment and Yield of Bioenergy Miscanthus on Claypan Soil Landscapes” have been refined and the manuscript submitted to the journal Industrial Crops and Products.
Grain Crop and Switchgrass Production
The goal of this research not only to afford farmers and educators the opportunity to observe all phases of producing energy crops (e.g. establishment, growth and development, and harvesting), but to compare them to conventional grain cropping systems. Both grain and switchgrass production has been measured at two research sites to help meet this objective. The first site was at the CRC and is the primary study associated with SARE proposal. The second site included grain and switchgrass production evaluation at the South Farm SPARC plots (previously described in the miscanthus rhizome study).
Production of Grain Cropping at Centralia Research Center.
For the CRC, grain cropping systems predates the bioenergy crops by about 15 years. Therefore the highest priority was to first summarize the impacts of landscape position on the various grain cropping systems. This then too would provide a baseline for grain cropping when both grain and bioenergy crops could be comopared. In a recently completed analysis of the grain crops (Yost et al., 2015), corn yield was equivalent among cropping systems on the summit landscape position, 13% higher for no-till corn-soybean and no-till corn-soybean-wheat on the backslope, and 14% lower for no-till corn-soybean-wheat on the footslope. Soybean yield was 8% higher on the summit, 24% higher on the backslope in no-till corn-soybean (NTCS) and no-till corn-soybean-wheat (NTCSW), and 12% higher on the footslope in NTCSW than mulch-till corn-soybean (MTCS). Corn yield was more stable in NTCS and NTCSW than MTCS and increased in stability from the footslope to summit. Soybean yield was less stable in NTCS and NTCSW than MTCS and landscape position effects on stability were similar to corn. The coefficient of variation (CV) of corn yield across years was 10 percentage points lower in NTCS and on the footslope, and of soybean yield was 10 percentage points lower at the footslope and summit. Wheat production was not affected by landscape position. Results indicate that conservation systems often can maintain grain crop productivity equal to, increase yield stability above, and reduce yield variability below those of a conventional system on claypan soils.
While switchgrass production has been measured since 2012 on the CRC plots, data have not been summarized for formal publication yet. General observations have indicated switchgrass yield have consistently been between 5 and 6 tons/acre, with little yield difference between landscape positions (not statistically tested yet). Additionally, subsamples of harvested material have been taken and analyzed for nutrient and forage quality. These results too have not been compiled, summarized, and analyzed as of the writing of this report.
Grain and switchgrass production at the South Farm SPARC plots has been measured over the last five years. Several stand-alone studies have been conducted and are currently being written or are in journal review. However, one analysis has been completed (Boardman et al., 2015). In this investigation water use efficiency (WUE) and crop N recovery efficiency (REN) from corn and switchgrass grown on variable soils representative of claypan soil landscapes were compared. Water use efficiency for variable DTC was simulated using an original water-balance model and yield. Measured yield and N content in grain and switchgrass biomass were used to calculate REN. Switchgrass resulted in greater WUE than corn (185-700%) for most growing seasons, generated less runoff (averaged 51%), but had more days of water stress (averaged ~50 days more annually). In dry years and depositional soils, switchgrass was greater than corn for both WUE and REN (50-55% greater). These results quantify the level of drought tolerance switchgrass has compared to corn when these two crops are grown on claypan soils. These findings, along with knowledge of field specific soil conditions, can help farmers know where to grow perennial bioenergy crops in lieu of corn to optimize water and N resources to increase bioenergy production. Two other manuscripts on grain and switchgrass production from SPARC research will be drafted and submitted in 2016.
Switchgrass Energy Yield
Quantifying switchgrass energy yield from the SPARC plots has also been investigated. Analysis included four harvest years (2010-2013). The energy yield lab work was conducted in collaboration with the USDA ARS lab in Lincoln, NE. This was done at no additional cost to this project. The student conducting this research did so as a part of his MS studies and successfully completed his thesis and defended it on June, 2015. The title of the thesis was Predicting Switchgrass Biomass and Ethanol Potential on Claypan Soil Landscapes. The title of the chapter relating to this sub-objective was Influence of Depth To Claypan and Management Practices on Switchgrass Biomass Yield and Ethanol Potential. This research found that ethanol production increased with greater depth to claypan soils, primarily an effect on biomass production and not on energy quality of the biomass. Likewise, ethanol yield increased with N rates for years with drier than average years of precipitation. The results will be submitted as a journal manuscript within the next year.
Water Quality Monitoring.
Importantly, soil and water data from the replicated plots at CRC would enable researchers to assess the environmental sustainability of growing dedicated energy crops. With help through this SARE grant, instrumentation has been installed at 18 of those plots for continuous runoff water quality and quantity monitoring. However, installation required several novel approaches over the last couple of years to address infrastructure and instrumentation challenges. Plot berms, flumes, and flume approaches were designed to facilitate efficient farming operations with field-scale equipment (Photo 8). Commercial runoff samplers were employed (Photo 9) in flow-proportional mode, but stage transducers available with the samplers did not have the required accuracy of 2 mm stage over the expected range in ambient temperatures. To meet this requirement, we designed a system based on a temperature-compensated differential pressure transducer mounted in a stilling well. A datalogger recorded stage data and controlled the sampler through a custom electronic interface. An electric heating system was installed to protect the stilling well and transducer from freezing down to approximately -10 C. A laptop-based program was developed to manage calibration and data downloads for the 18 systems, and a wireless telemetry link was established. With these corrections and enhancements, the 2015 growing season marks the first year reliable runoff and sampling has been achieved (Figure 4). This work of instrumentation for runoff and water quality sampling was documented in a proceedings paper (Sudduth et al., 2015). The impact of grain and bioenergy cropping systems on runoff and water quality will be evaluated after 3-5 years of reliable runoff results have been obtained.
Soil Quality/Soil Health
Because the inclusion of bioenergy crops for the CRC and South Farm SPARC plots have only been in place for the last 3-5 years, time has been insufficient to allow for quantifiable changes in soil quality parameters. However, baseline samples were taken from all plots that switchgrass and miscanthus bioenergy crops were introduced on. Sometime in the 8-10 year window after introduction these will be resampled and compared not only to the baseline but to the grain cropping systems. That said, because grain cropping practices have been in place for over 20 years at CRC and this allowed for soil health on these production systems and other Salt River Basin fields to be assessed and published (Veum et al., 2015). From this investigation, soil quality was evaluated using a range of soil chemical, physical, and biological measurements within the Soil Management Assessment Framework (SMAF). The SMAF translates multiple laboratory measurements into comprehensive scores related to crop productivity, environmental protection, and other important soil functions. This study used the SMAF to evaluate the soil quality benefits of several different conservation management practices including Conservation Reserve Program (CRP) systems, prairie restoration, perennial working grasslands (i.e., pasture, forage, and hay production), tillage reduction, increased crop rotation diversity, and incorporation of cover crops. In the surface soil layer (0–2 in), SMAF soil quality scores were the highest for systems with permanent, vegetative cover and living roots (e.g., CRP), ranging from 88 to 98 percent. Annual cropping systems scored lower than perennial systems, ranging from 76 to 87 percent. Among annual grain cropping systems, systems that incorporated cover crops scored the highest (87 percent), followed by no-till systems without cover crops (85 percent), and tillage systems lacking cover crops (76–84 percent). Based on the results of this study, restoration of degraded or marginal soils would realize the greatest soil quality benefits from perennial CRP systems including either cool- or warm-season grasses with legumes, followed by working grasslands and pasture systems. We would anticipate bioenergy crops to produce similar findings. Perennial systems such as these have dense roots that can protect highly erodible soil, increase soil organic matter, and stimulate nutrient cycling. Conversely, reversion of CRP acreage to annual row crops may potentially lead to substantial losses in soil quality under certain conditions. For cultivated, annual row cropping systems, prudent management integrating no-till with diverse cover crops and crop rotations can protect, improve, restore, and/or maintain soil quality.
- Photo 1. Graduate student Brain Randall applying N treatments to miscanthus trials.
- Figure 1. Leaf chlorophyll measurements (SPAD) for 2014 by location in relation to month and N fertilizer rate.
- Photo 2. Graduate student Brain Randall harvesting N miscanthus trials.
- Photo 3. Aerial view of miscanthus harvesting.
- Figure 2. Yield for 2014 by location and nitrogen fertilizer rate.
- Figure 3. Early and late season shoot counts in relation to rhizome length, weight, and rhizome score.
- Photo 5: First miscanthus shoot emergence 10 days after planting.
- Photo 7. Harvesting switchgrass off of SPARC plots.
- Photo 9. Plot sampling system operating in late-winter snowmelt. Upstream view of flume outlet and Sigma sampler (left) and downstream view of flow through concrete flume approach (right).
- Figure 4. These results from 2015 demonstrate that the stage and sampling equipment are now working reliably. Stage (top) and cumulative flow and sip request (bottom) data for May 28, 2015 runoff event on three plots.
- Photo 8. Plot berm soon after construction, with concrete approach and flume in place (left). Tractor crossing berm during harvesting of perennial grass crop (right).
- Photo 4. After rhizome quality characterization, 10 randomly-selected rhizomes were hand-planted to a 10 cm depth, on ~ 5-m spacing, on each of the three landscape positions.
- Photo 6: Basal circumference measurements taken before harvest.
Since this funded research was integrated within other research funded research projects, in some cases supporting similar objectives, it is difficult to tease out results with impact that can be attributed alone to the SARE project. However, this project has helped contribute to some meaningful findings and outcomes, such as:
(1) Establishment of the willow on claypan soil landscapes was unsuccessful because of the droughty conditions often experienced on these upland soils. In order to make such successful, supplemental irrigation might be necessary, particularly during the establishment phase.
(2) Newly planted miscanthus rhizomes performed very well on eroded parts of the landscape. Further, rhizomes that were longer and/or had greater mass had the most positive effect on establishment.
(3) Ethanol production of switchgrass increased with greater DTC for years with drier than average years of precipitation, and with N fertilization for most all years.
(4) Switchgrass compared to corn resulted in greater water use efficiency, ~50% greater crop N recovery efficiency, and generated about 50% less runoff.
(5) Income variability was greater for corn and soybean grain crops than for miscanthus or switchgrass on claypan soils, largely because year-to-year price volatility and weather differences impacted grain yield more than bioenergy crops.
The only economic analysis that was conducted was a related investigation funded under another project whereby the profitability of five different cropping systems (switchgrass, miscanthus, corn (Zea mays), soybeans (Glycine max) and fescue pasture (Festuca arundinacea) were compared on three different soil profiles common in northeast Missouri (an upland, noneroded soil, an eroded soil, and floodplain soil) (Dolginow et al., 2014). In this study, income variability was found to be greater for corn and soybean grain crops than for miscanthus or switchgrass, largely because year-to-year price volatility and weather differences impacted yield of grain crops more than it did for bioenergy crops for these soils. From this we concluded that a risk-averse producer might consider forgoing potentially higher profitability to lower their income variability by growing miscanthus rather than corn or soybean. Also, crop insurance for corn and soybean could affect the decision to plant perennial bioenergy grasses for risk-averse producers.
Early-adopter farmers working in concert with company leading the Missouri/Arkansas miscanthus BCAP project (originally MFA Oil Biomass, Columbia, MO, now operated by Renew Biomass LLC/M-Fiber, Springfield, MO) have established pilot plantings of miscanthus. Their goal was to provide feedstock to potential markets in Mid-Missouri. At the present time, the miscanthus biomass is not being used for bioenergy because no market has developed. In the meantime, Renew Biomass has explored other viable economic options for using this commodity. Regardless, the less-intensive management in producing these perennial crops compared to conventional grain cropping systems should reduce soil erosion and improve both soil structure and health. In total, there are about 20,000 acres of production miscanthus in the two state area.
The results of this research are contributing to the successful management practices and productivity of switchgrass and miscanthus on degraded soil landscapes. These findings will help farmers know where to grow perennial bioenergy crops in lieu of grain crops in order to optimize production and minimize negative environmental effects with perennial plant bioenergy production. The findings are also being directly used by farmers who are growing miscanthus in Missouri and Arkansas. Of particular interest are the results regarding miscanthus N requirements for optimal production and rhizome quality impacts on establishment.
Educational & Outreach Activities
Direct Publications. The following are publications that directly resulted from this SARE grant.
Randall, B.K., M.A Yost, N.R. Kitchen, E. Heaton, E. H. Stelzer, and A. Thompson. 2015. Impact of rhizome quality on miscanthus establishment in claypan soil landscapes. Industrial Crops and Products. (In journal review)
Boardman, D.L., Kitchen, N.R., Allphin, E.B., and Thompson, A.L. Water and nitrogen use efficiency of corn and switchgrass on claypan soil landscapes. Proceedings of the International Conference on Precision Agriculture, July 20-23, 2014, Sacramento, CA, 2014. (oral presentation)
Randall, B.K., Kitchen, N.R., Heaton, E. Myers, D.B., and Thompson, A. 2014. Management factors affecting establishment and yield of bioenergy miscanthus on claypan soil landscapes (online). In 2014 ASA-CSSA-SSSA annual meeting abstracts. Long Beach, CA, Nov. 2-5, 2014. ASA Madison, WI. (poster presentation)
Randall, B.K., Kitchen, N.R., Heaton, E. Myers, D.B., and Thompson, A. 2014. Nitrogen Management of Bioenergy of Miscanthus on Claypan Soil Landscapes. 2014 North Central Extension-Industry Soil Fertility Conference, November 19-20, Des Moines, IA. pp. 141-146. (poster presentation)
Sudduth, K.A., C. Baffaut, S.T. Drummond, and E.J. Salder. 2015. Instrumentation for full-year plot-scale runoff monitoring. ASABE Annual Inter. Mtg. New Orleans, LA, Jul 26-29, 2015, Paper No. 2189840. (oral presentation)
Indirect Publications. SARE funding indirectly benefited two other related research projects conducted on the same field research sites in Centralia and South Farm.
Dolginow, J.P., Massey, R.E., Kitchen, N.R., Myers, D.B., and Sudduth, K.A. 2014. A stochastic approach for predicting the profitability of bioenergy grasses. Agron. J. 106:2137-2145. doi:10.2134/agronj14.0110
Veum, K.S., Kremer, R.J., Sudduth, K.A., Kitchen, N.R., Lerch, R.N., Baffaut, C., Stott, D.E., Karlen, D.L., Sadler, E.J. 2015. Conservation effects on soil quality indicators in the Missouri Salt River Basin. Journal of Soil and Water Conservation. 70:232-246. DOI: 10.2489/jswc.70.4.232.
Yost, M.A., Kitchen, N.R., Sudduth, K.A., Sadler, E.J., Baffaut, C., Volkmann, M.R., and Drummond, S.T. 2015. Long-term impacts of cropping systems and landscape positions on clay-pan soil grain crop production. Agron. J. (accepted 11/1/2015).
Boardman, D.L., E.B. Allphin, N.R. Kitchen, K.A. Sudduth, S.T. Drummond, A.L. Thompson. 2015. Water and nitrogen use efficiency of corn and switchgrass compared on a variable claypan-soil landscape. Agron. J. (accepted with minor revision)
2012 SARE Field Day: Translating Missouri USDA-ARS Research and Technology into Practice, SARE-sponsored training for Univ. of Missouri Extension and NRCS Staff, Oct. 11-12, Columbia-Centralia, MO, (~40 in attendance).
2014 Goodwater Creek Field Day: Cover Crops, Bioenergy, and Sustainable Production, Sept 5, Centralia, MO. (~110 in attendance). Post-event surveys revealed that farmers and educators who attended the field day increased their knowledge of the soil-enhancing benefits of producing dedicated energy crops on marginal claypan soils. They further learned some of the “do’s” and “don’ts” in establishing and maintaining these crops.
Series of 10 Columbia Tribune Newspaper articles on the miscanthus BCAP program in mid-Missouri, including several related to the collaboration work of this research project.
“Biomass crops provide benefits to marginal soils”. Delta Farm Press
“Biomass crops benefit marginal soils”. News from Univ. of Missouri Extension
“Switchgrass and Miscanthus: Economics of Perennial Grasses Grown for Bioenergy” University of Missouri Extension Guide Sheet.
Website: Missouri Crop Resource Guide: Bioenergy Grasses, created while working on this project:
Areas needing additional study
From the results of this research, we have identified the following areas needing further study: (1) Impacts of perennial bioenergy crops on soil health, (2) Improving methods of miscanthus establishment, perhaps even as no-till, and (3) Understanding the long-term fertility requirements of miscanthus production