Production Requirements
Soil Types: Miscanthus is suited to most soil types. Yields are lower on extremely heavy or light soils
Soil pH: 5.4–6.8
Recommended Rotational Crops: Miscanthus is a long-term perennial and crop rotations do not apply. Wheat or other cereals may act as a nurse crop during establishment
Minimum Soil Temperature: 4°C for planting rhizomes and 10˚C for planting plants or plugs
Optimum Air Temperature: 24°C–29°C
Earliest Planting Date: Early to late May
Required Growing Season: Perennial crop 10+ years
Miscanthus is a relatively new perennial crop for Ontario that has industrial and agricultural uses for fibre, biocomposites, paper, bioenergy (liquid and solid), livestock and poultry bedding and ginseng bedding.
Variety Selection
Miscanthus is a perennial C4 rhizomatous grass originating from Asia. Varieties range in their frost tolerance and winter hardiness, so proper variety selection for particular growing regions is important. Breeding for new varieties is limited. The Biomass Producers’ Co-op website (www.ontariobiomass.com) lists varieties and other variety specific information.
As a result of its perennial nature, miscanthus tends to be more drought tolerant than annual crop types. The crop goes into a conservation mode during dry periods but is able to continue growth quickly when the drought period passes. Yield declines due to dry conditions tend to be much less than experienced with annual crops.
Planting
Miscanthus is established using rhizome transplants, rhizome plugs or seedling plugs and is generally spaced at 1 m (3 ft) between and within rows. The final stand should be approximately 12,000 plant/ha (4,850 plant/acre). Plant good quality rhizomes when sufficient soil moisture is available to ensure adequate stand establishment.
Greenhouse seeding or propagation can be started 4–8 weeks prior to field planting. Field transplanting is best from mid-April to May, after risk of frost has passed. Weed control is required during the establishment year as the newly emerging plants are slow growing and non-competitive following planting.
Techniques are being developed to harvest rhizomes out of the field, process them for size and plant them into new fields within days of harvest. Rhizomes must be protected from desiccation between root stalk harvest and replanting.
Fertility Management
Limited Ontario fertility guidelines exist. Research and recommendations from outside Ontario do not necessarily apply to Ontario growing conditions. Nitrogen requirements will depend on growing location, soil type and market conditions. Ontario research suggests that a range between 80–115 kg/ha N (70–100 lb/acre N) provides the best crop response. Excess nitrogen can cause crop lodging in some varieties, which will affect crop quality and ease of harvest. Nitrogen fertilizer should not be applied during the seeding year because it encourages weed competition. Table 7–4, Range of nutrient removal rates of fall-harvested and over-wintered miscanthus varieties in Ontario (Engbers 2012) and compared to literature values shows the range in nutrient removal from various harvest timings and methods.
The amount of phosphorus and potassium required will depend on the harvest method used. Miscanthus that is harvested in late fall or from spring-baled windrows will have lower requirement for phosphorous and potassium because these nutrients leach out of the biomass. Harvest in the summer or early fall will remove more of these nutrients with the harvested biomass. Phosphorus and potash fertility should be at target soil test levels (12–18 ppm P and 100–130 ppm K). If soil phosphorous and potassium levels are below target ranges, incorporate these nutrients into the soil ahead of planting, at rates that meet crop removal rate plus an amount that will build up the soil test over time.
Table 7–4. Range of nutrient removal rates of fall-harvested and over-wintered miscanthus varieties in Ontario (Engbers 2012) and compared to literature values
Harvest and Storage
Harvest
Miscanthus is commonly harvested in one cut each year and the harvest method will depend on the end use of the crop. Miscanthus is typically harvested in late winter or left standing over winter and then harvested in early spring. Allowing the crop to stand over winter will improve stem dry down, leaf drop, and nutrient movement to the roots and soil by translocation and leaching. Spring-harvested miscanthus will have approximately 10% moisture content and will be of higher quality for combustion with less “clinkers.” Fall harvest will yield up to 25% more but is higher in moisture at cutting. Summer or early fall harvest (prior to natural senescence) could reduce winter hardiness and stand longevity. Standard field-crop equipment including sickle/disc mowers, haybines, round/large square balers and forage harvesters are able to handle this voluminous crop. Currently there are no established grades. Quality specifications are determined by the market.
Storage
Storage will depend on end use. Miscanthus has been stored in ag-bags; under cover in a building, as well as outside — with and without tarps. Miscanthus straw deteriorates less rapidly than cereal straw. Further processing may be required, such as chopping, pelleting and other treatments that will increase the density and improve storability of the crop.
Weed Control
Weed control options are limited, so select field sites with low weed pressure. A herbicide burn-down using a non-selective herbicide, such as glyphosate, in the previous fall can aid in reducing pressure from winter annuals and biennial weeds. The stale seedbed technique prior to planting is useful when there are few options to control weeds once a miscanthus crop has been planted and is emerged. The stale seedbed technique involves working the soil well before planting; where weeds are allowed to emerge for several weeks followed by the application of a non-selective herbicide, like glyphosate, to kill emerged weeds. Seeding or planting directly into the killed weeds, with minimal soil disturbance will allow the crop to establish before the next flush of weed emergence. In general, control of grassy weeds is more difficult because herbicides that are effective against grasses cause unacceptable injury to miscanthus. The extent of crop injury caused by herbicides depends on the propagule type (e.g., seed, plug/transplant, rhizome) and also on variety or genotype.
Insects and Diseases
In Ontario, there are no known insect or disease pests that cause economic losses to miscanthus at this time. Nematodes and rabbits have caused some issues. In other regions, European corn borer and western bean cutworm have been identified as insect pests. Few pest control products are registered on this crop.
For further production information, go to ontario.ca/crops.