This report summarizes the findings of the field-scale agricultural biomass research and development project undertaken by Ontario Soil and Crop Improvement Association (OSCIA). The project was as a component of a larger study of developing an agricultural biomass value chain sector in Ontario lead by the Ontario Federation of Agriculture (OFA). Support was provided for Ontario farmers to obtain on-farm pilot scale field-plot experience with purpose grown biomass crops over four growing seasons (2010-2013). By encouraging this adaptive research, it would allow farmers, who are very adept at developing solutions to their individual problems and circumstances, to develop site-specific solutions to agronomic and productive capacity challenges with purpose-grown biomass crops.
Twenty eight producer co-operators were selected based on submissions of Applications of Interest and reviewed by a selection committee comprised of OFA, OSCIA, OMAF and MRA extension staff and University of Guelph researchers. Eleven co-operators had biomass crops already established while 17 new planting projects were planted in the spring of 2012. Three purpose grown biomass crops were targeted as the focus of the study, these included; Miscanthus, switchgrass and tallgrass prairie. These species were selected for their high yield potential, high energy and nutrient efficiency and wide adaptation of C4 perennial grass species relative to dedicated annual species in Ontario. Prior to this project, field production experience in Ontario with Miscanthus, switchgrass and tallgrass prairie has been limited to a few early adopters and research trials. Information on producer experiences with all aspects of biomass grass production were obtained through annual co-operator surveys, co-operator reported yields and harvest moistures and field data collected by OSCIA staff.
The 28 producer co-operators experiences were broken down into 56 plots to capture different comparisons of species, ecovars, year of establishment, and planting method. Plots represented a wide range of soil types, land classifications and a wide geographic dispersion. Field selection and preparation, variety selection, planting methods, planting timing and establishment, weed management practices and corrective measures for poor stand establishment used by co-operators are outlined in detail in this report. Field selection/preparation, planting timing and weed management were the key factors impacting crop establishment success and yield potential.
Field preparation for successful crop establishment was not crop, location or soil specific but specific to the cropping system being displaced. Soybeans are the preferred crop to precede establishment of biomass grasses as they are associated with little residue, the opportunity to use no tillage which enables a firm seedbed preferred by switchgrass and native tallgrass prairie, and are associated with primarily an annual weed complex that is less competitive and easier to control subsequent years. Conversely establishment of biomass grasses into hay, pasture or alfalfa can be difficult due to the need for tillage to control the previous crop, and the presence of a more competitive, more difficult to control perennial weed complex.
Planting timing also strongly influenced the establishment success and weed pressure of the biomass plots in this program. April to May planting of all grasses resulted in increased establishment success compared to later plantings. Early planting has lower weed pressure and competition for sunlight, soil moisture is higher and there is a longer growing period. Delayed planting date and increased winterkill were the most common cause of stand failure reported by co-operators in all of the biomass crops.
In addition to reducing the potential weed pressure by early planting into a field with minimal tillage and a less competitive annual weed complex. Weed management practices were investigated by co-operators to encourage successful establishment. Mowing of weeds in the spring and early summer above the establishing grass crop seedlings was most commonly used in the initial establishment phase. Beyond the first year of planting, herbicide use was most common method of weed management. There are currently no herbicides registered for use on Miscanthus, switchgrass and tallgrass prairie. Co-operators were required to base herbicide decisions on recommendations from other jurisdictions and from the limited herbicide evaluation studies conducted to date in Ontario. Co-operators used a wide range of herbicides. The herbicides used are currently registered for use on other crop species grown in Ontario and application rates and use patterns for Miscanthus, switchgrass and tallgrass prairie were similar to that used in crops currently on the respective herbicide labels.
Co-operator experiences with crop fertility requirements, insect and disease pressure and lodging were all documented by the study but were not considered major influencing factors in crop establishment. However as stands mature fertility requirements, monitoring insect and disease pressure and lodging will likely become of greater concern to producers for maximizing yield potential. Producers based fertility management decisions on recommendations from other Ontario biomass grass producers, production guides, research trials by the University of Guelph and OMAF and MRA and recommendations from the seed or rootstock suppliers. Complexities observed in general recommendations of field crop species, such as corn, may need to be developed for switchgrass, Miscanthus and tallgrass prairie. Further research will be required to develop crop specific fertilization recommendations of established crops as the biomass industry develops in different regions of Ontario.
The lack of observed insect and disease pressure by co-operators in this project is consistent with the observation by producers and researchers from other regions that there are currently few insect and disease pests of economic concern to Miscanthus, switchgrass and tall grass prairie. However, as acreage of these crops increase in Ontario monitoring of insect and diseases is required.
Lodging of perennial grass biomass stands is a concern because lodging can negatively impact yield, biomass quality and harvest efficiency. The extent of the impact is presumably related to the degree of lodging and recovery from lodging that occurs. Based on observations in the present project, Miscanthus, switchgrass and tallgrass prairie all have the potential to lodge. Co-operators did not report lodging having affected harvestable yields in any of the grasses from 2010 to 2012. However, as maturing stands near closer to maximum yield potential and fertility requirements continue to be investigated the potential for lodging and its effects on harvestable yield will need to be monitored.
Harvesting of biomass crops was done with existing field equipment in the spring. Switchgrass and tallgrass prairie plots were mowed in the fall and baled in the spring while Miscanthus was left standing overwinter and baled in the spring. Baling using a large square baler in the spring is optimal for low harvest moistures (6-12%) and maximum bale weight for transport. When baled at the low moisture contents reported no problems with storage either indoors or outdoors were reported. The low moisture contents may also reduce drying costs and transportation costs to the end user.
Yields reported by co-operators were highly variable with age of establishment, location and within crop species. Established (≥ 3 years) Miscanthus plots achieved an average yield of 18 t ha-1, while established switchgrass plots achieved an average yield of 3.6 t ha-1. Miscanthus yields observed by co-operators are in line with literature estimates for Ontario ( Kludze et al. 2011). However co-operator reported switchgrass yields are much lower than literature estimates for Ontario (Samson, 2007). Switchgrass plots in this program may have represented more northern locations with shorter growing seasons and marginal soils than addressed in research programs in Ontario to date. Overall, co-operators commented that stands were slower to establish than expected and time to achieve reasonable yields took longer than anticipated. Further research is required to determine the time required to reach full yield potential of the different grasses, and switchgrass in particular, across Ontario.
In conclusion, Ontario biomass producers have been able to develop site-specific solutions to agronomic and productive capacity challenges with Miscanthus, switchgrass and tallgrass prairie crop production. However other more specific questions related to variety selection, control of perennial grass weed pressure, fertility requirements and the time required for achieving full yield potential in a range of soil and climactic conditions still remain. The lack of stable biomass markets and end-uses has delayed the development of specific agronomic recommendations. As more stable and profitable markets evolve agronomic and productive capacity challenges will continue to be developed by Ontario farmers.
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