skip to content

Grass Management for Biomass

 

If and when a market exists for grass pellets, the following are suggested guidelines for agronomic management of grasses for biomass.

  1. If you want to establish and manage a grass biomass crop, go to (A).
  2. If you want to manage an existing grass stand, go to (B).
  3. If you want to use minimum management on established grass meadows, go to (C).

 

(A). You want to establish and manage a grass biomass crop Back to key

  1. If you want to establish switchgrass, go to (D).
  2. If you want to establish a cool-season grass, go to (E).

 

(D). You want to establish switchgrass Back to key

Switchgrass has been tested for biomass production in Canada and in much of the eastern 2/3 of the USA. Lowland varieties are very productive in the South but are subject to winter injury in the north. The observation that switchgrass varieties are susceptible to winter injury if grown more than 300 miles north of their origin was recently reaffirmed in North Dakota (Berdahl et al., Agon. J. 97:549. 2005). Upland varieties, developed in drier, upland sites, are more winter hardy, but are not tolerant of the poor drainage conditions often found in the Northeast. Potential switchgrass yields by soil type for NY can be found using the Biomass Species Selector.

Variety Selection:

Considerable switchgrass selection is ongoing in the northern USA, but at the present time Cave-in-Rock is still the most popular variety for the northeast USA. Cave-in-Rock was selected from a native switchgrass stand in Illinois in 1958. Other more recent upland varieties such as Pathfinder and Sunburst should also do reasonably well in the Northeast.

Stand Establishment:

From an establishment perspective, switchgrass requires intensive management or seeding failure is a good possibility. Switchgrass does best on well-drained soils. Take a soil sample the fall before seeding and fertilize with P and K according to soil test recommendations. Liming is needed if soil pH is below 6.5. Typically no nitrogen fertilizer is applied to switchgrass in the seeding year, because it encourages weed growth more than switchgrass growth. Seeding should be done in the spring in mid to late May in the Northeast. Suggested seeding rate is 8-10 lbs pure live seed/acre. Although switchgrass can be sown no-till, it is best to seed into a tilled, very firm seedbed. Seed should be sown ¼ to ½ inch deep, but no deeper. Chemical weed control is generally required in the seeding year. Multiple mowing at or above the seedling height may help to control weeds.

Stand Management:

Following the seeding year, weeds could be controlled in switchgrass by field burning in late fall or early spring if legal, but such a practice would burn up your biofuel profits for a year. Establishment year growth should be left to overwinter and harvest the following spring to maximize the chances of a vigorous stand in the second year. Maximum biomass production will likely not be attained until the third growing season, but a well-managed stand may persist for 10 years or more. Switchgrass may not respond significantly to P or K fertilization following the seeding year. For each production year, 50 to 100 lbs of actual N can be applied for maximum yields.

Harvest Management:

Fall harvest of this late maturing crop may be difficult; a wet fall would not provide much opportunity to bale dry hay. If harvested in the early fall, a 6-inch stubble height should be left to minimize stand injury and provide some winter/spring cover for wildlife. A late fall harvest has no risk of stand injury, and a 6-inch stubble height is not required. Switchgrass left in the field over the winter may be as low as 2% ash the following spring, due to leaching of herbage and the loss of higher-ash plant parts such as inflorescence and leaf. Overwintering will come at a cost, with a yield reduction from 15% to as high as 50% in the Northeast.


 

(E). You want to establish a cool-season grass Back to key

The cool-season grass species with the highest production potential for biomass in the Northeast is reed canarygrass, although tall fescue, timothy, smooth bromegrass, and orchardgrass are also capable of produce high yields with persistent stands. Of the above species, the one that suffers the most from occasional winter killing in the Northeast is orchardgrass. Potential yields by soil type for reed canarygrass in NY can be found using the Biomass Species Selector. Reed canarygrass can be grown on all agricultural soil types in NY. Cool-season grasses all have higher ash content than warm-season grasses such as switchgrass.

Variety Selection:

  • Reed canarygrass: Any seed you can buy with reasonable germination will probably work for biomass purposes. If you want the option to use the forage for cattle feed, then make sure a low-alkaloid variety is chosen (Palaton, Rival, Bellevue, Marathon etc.). Seeding rate: 12-15 lbs/acre.
  • Tall fescue: Kora has performed the best so far in NY trials. Others that have produced good yields include Festival, Barcarella, Fuego, Select and Hoedown. All of these would be dual purpose, biomass or forage. If seed was available of an older endophyte-infected forage-type variety it might be the best choice if planted exclusively for biomass. Endophyte-infected turf-type tall fescue varieties would not be acceptable for biomass purposes. Seeding rate: 15-20 lbs/acre.
  • Timothy: A late maturing variety would be best for biomass. Most varieties are now selected for early maturity to be more compatible with alfalfa in mixtures. Seeding rate: 8-10 lbs/acre.
  • Orchardgrass: A late maturing variety would be best, most new varieties are late maturity types. Seeding rate: 10-12 lbs/acre.
  • Smooth bromegrass: Any available variety would work. Seeding rate: 12-15 lbs/acre.
  • Perennial ryegrass: Completely unacceptable for biomass purposes because of the risk of winter damage in the Northeast US.

Stand Establishment:

Take a soil sample the fall before seeding and fertilize with P and K according to soil test recommendations. Maintain soil pH at 6.0. From 30 to 50 lbs of N can be applied at seeding. Seeding should be done in the spring as soon as a good seedbed can be prepared. Seeding can also be done in the late summer in early August. Spring and late summer seedings are equally successful in NY. Suggested seeding rates as pure live seed/acre are included with individual species under Variety Selection. Cool-season grasses can be sown no-till successfully, but it is best to seed into a tilled, very firm seedbed. Seed should be sown 0.25 to 0.5 inch deep, but no deeper. Chemical weed control could be used in the seeding year, or multiple mowing at or above the seedling height will control weeds. A light seeding of oats as a companion crop can also be used to facilitate weed control in the seeding year.

Stand Management:

No weed control is necessary in the years following establishment. No insect control is needed, except possibly the occasional years of severe army worm infestations. Occasional P and K fertilization will be required on sandy soils. Heavier soils may not show any significant response to P or K fertilization of established stands. All cool-season grasses respond to N fertilization, with a linear response in yield from 0 to 100 lbs N/acre. Economic responses to N fertilizer are possible at much higher levels of N fertilization; however, from an environmental standpoint N fertilization should not exceed 150 lbs N/acre. All N should be applied at spring green-up. An alternative to N fertilization is to apply animal manure in the spring and/or after harvest. Manure could be applied any time after harvest while the grass is still actively growing, traffic damage in regrowth is not an issue as it is not harvested. Regrowth is left unharvested to provide winter/spring wildlife cover and to maintain soil sustainability.

Harvest Management:

Grass should not be harvested until the plants are fully mature, between mid-July and early September. Ash content of biomass declines with grass maturation. An early August harvest might be best, allowing time for in-field leaching of cut biomass and allowing time for manure application following biomass removal from the field. Cut grass should be left on the field for a week or two to allow for leaching. A tedder can be used to re-dry windrows, being careful to set the teeth high enough to minimize soil contamination of biomass. Some of the grass plant may break off and be lost as harvestable yield during the field leaching period, but the inflorescence and leaf lost are relatively high ash content compared to the stem. Bale the hay at low enough moisture to prevent excessive heating/molding in storage.


 

(B). You want to manage an existing grass stand Back to key

Any mixed grass field that undergoes fertilization and harvest will have a shift in species composition and most likely some decline in species diversity. Yield will be increased significantly by more intensive management.

Stand Management:

No weed control is necessary in the years following establishment. No insect control is needed, except possibly the occasional years of severe army worm infestations. Occasional P and K fertilization will be required on sandy soils. Heavier soils may not show any significant response to P or K fertilization of established stands. All cool-season grasses respond to N fertilization, with a linear response in yield from 0 to 100 lbs N/acre. Economic responses to N fertilizer are possible at much higher levels of N fertilization; however, from an environmental standpoint N fertilization should not exceed 150 lbs N/acre. All N should be applied at spring green-up. An alternative to N fertilization is to apply animal manure in the spring and/or after harvest. Manure could be applied any time after harvest while the grass is still actively growing, traffic damage in regrowth is not an issue as it is not harvested. Regrowth is left unharvested to provide winter/spring wildlife cover and to maintain soil sustainability.

Harvest Management:

Grass should not be harvested until the plants are fully mature, between mid-July and early September. Ash content of biomass declines with grass maturation. An early August harvest might be best, allowing time for in-field leaching of cut biomass and allowing time for manure application following biomass removal from the field. Cut grass should be left on the field for a week or two to allow for leaching. A tedder can be used to re-dry windrows, being careful to set the teeth high enough to minimize soil contamination of biomass. Some of the grass plant may break off and be lost as harvestable yield during the field leaching period, but the inflorescence and leaf lost are relatively high ash content compared to the stem. Bale the hay at low enough moisture to prevent excessive heating/molding in storage.


 

(C). You want to use minimum management on established grass meadows Back to key

Low intensity management of existing old grass meadows consists of one summer harvest with no weed, insect or disease control and no commercial N, P or K fertilization. A few soils may be low enough in native fertility so that they are not able to produce enough yield to justify the cost of harvesting. This is dependent on machinery efficiency; high capacity mowing equipment with some option for merging windrows would significantly reduce overall harvesting costs. Spring or post-harvest manure applications could be applied to these meadows to significantly increase yields. Regrowth is left unharvested to provide winter/spring wildlife cover and to maintain soil sustainability.

Harvest Management:

Grass should not be harvested until the plants are fully mature, between mid-July and early September. Ash content of biomass declines with grass maturation. An early August harvest might be best, allowing time for in-field leaching of cut biomass and allowing time for manure application following biomass removal from the field. Cut grass should be left on the field for a week or two to allow for leaching. A tedder can be used to re-dry windrows, being careful to set the teeth high enough to minimize soil contamination of biomass. Some of the grass plant may break off and be lost as harvestable yield during the field leaching period, but the inflorescence and leaf lost are relatively high ash content compared to the stem. Bale the hay at low enough moisture to prevent excessive heating/molding in storage.