Atmospheric concentrations of carbon dioxide can be lowered either by reducing emissions or by taking carbon dioxide out of the atmosphere and storing in it terrestrial, oceanic, or freshwater aquatic ecosystems. A sink is defined as a process or an activity that removes a greenhouse gas from the atmosphere. The long-term conversion of grassland and forestland to cropland (and grazing lands) has resulted in historic losses of soil carbon worldwide but there is a major potential for increasing soil carbon through restoration of degraded soils and widespread adoption of soil conservation practices.
Soil conservation practices not only reduce soil erosion but also increase the organic matter content of soils. Principal conservation strategies, which sequester carbon, include converting marginal lands to compatible land use systems, restoring degraded soils, and adopting best management practices. For example, removing agriculturally marginal land from annual crop production and adopting an ecologically compatible land use, such as livestock grazing and/or wildlife habitat, can lead to increases in total biomass production and an increase in carbon content in the soil.
The following best management practices have been proven to sequester soil carbon:
Canadian cropland can sequester about 22 million tonnes of atmospheric CO2 per year by using current best management practices. Canadian grazing land can sequester 3 million tonnes of atmospheric CO2 annually by controlled grazing, fire management, use of fertilizers, improved cultivars, and wetland restoration. ( National Climate Change Process: Sinks Options Paper, 1999).
While our lands can be managed to increase carbon storage, the increase can only temporarily offset greenhouse gas emissions. Many view land-based carbon sinks as buying valuable time to address the more significant challenge - reducing greenhouse gas emissions.
Yes. The soil and water conservation practices that sequester carbon were originally developed to address environmental concerns related to agriculture like soil erosion, organic matter depletion and soil salinity. Adoption of appropriate conservation strategies lead to enhancement of overall environmental quality through:
Ideally, two low residue crops wouldn't be seeded in succession due to erosion potential concerns and low snow trap potential. However, in years when the situation is unavoidable, there are a couple of considerations. If peas are seeded first, there is less plant material to be infected by sclerotinia. Also, there are foliar sprays available for sclerotinia control in canola while none are available for peas. If canola is seeded first, sclerotinia infection of peas usually occurs late in the year, after seed set and overall, peas are not as susceptible to sclerotinia. So from the disease perspective, canola could be seeded first, then peas. A cereal following the peas could then take advantage of rotational benefits such as soil conditioning and available nitrogen.
Broadleaf weed control is always a concern when seeding broadleaf crops in succession. Herbicide tolerant canolas enable better broadleaf control but close attention must be paid to herbicide rotation. In a situation where Clearfield canola and peas are seeded in succession, Odyssey will not control volunteer canola in the peas or volunteer peas in the Clearfield canola. A major concern is growing peas followed by canola. The standard pea herbicides, Odyssey and Pursuit, leave residues that may affect canola (other than Clearfield varieties). These carry-over effects will vary from year-to-year and field-to-field. They can be expected to be worse in drier years, in fields with lower organic matter, and in soils with low pH. If Clearfield canola is grown following peas treated with Pursuit or Odyssey, the application of Odyssey or Absolute may increase concerns over Group 2 resistance as well as carry-over into the following year due to herbicide stacking.
Before planting peas and canola in succession, consider the risks and seed accordingly.
Like other canolas, the plants are sensitive to phenoxies such as 2,4-D and MCPA. If the field is going into wheat or barley, volunteers may be sprayed one day prior to seeding. Another pre-seed herbicide option is Pre Pass and it too comes with the restrictions that only wheat, barley and oats may be seeded immediately after application. At time of writing, Monsanto has applied for registration of a couple of Roundnup tank mixes for pre-seed. Consult with Monsanto for updates on these registrations.
In crop, the plants are susceptible to a number of broadleaf herbicides. Read the herbicide jug labels and consult the provincial weed control guide before applying any herbicide. These sources will indicate any cropping and recropping restrictions.
Other ways to control RR canola volunteers in succeeding years is to leave the seeds near the soil surface the year the RR canola is harvested. Do not till in the fall. While this will increase the number of volunteers the following spring, there will be fewer volunteers in succeeding years.
This canola is sensitive to Roundup and other glyphosate products so can be controlled with a pre-seed application. In cereal crops, adequate control of the Clearfield canola volunteers will not be achieved by Group 2 products alone. Consult the provincial weed control guide for the list of herbicides and tank mixes that will control the volunteers .
While flax is not usually seeded following canola, there are a number of herbicide options available for in-crop control of the Clearfield volunteers in flax. Again consult the provincial weed control guide. When controlling Clearfield volunteers in peas, the options are a little more limited. Contact the Clearfield sales rep for recommendations.
Once Clearfield wheat is registered, growers will have a herbicide option for control of Clearfield volunteers in the wheat.
This is the HT canola least likely to cause a problem as a volunteer. Group 10 glufosinate ammonium is not registered for any. And no other Group 10 is registered for in-crop weed control. All broadleaf herbicides control Liberty Link canola. Roundup or glyphosate and the phenoxies will control these volunteers pre-seeding.
Compas 480 EC is the herbicide used for control in Navigator. It's a Group 6 with bromoxynil as the Active Ingredient. Volunteers will not be controlled in a cereal crop if a bromoxynil-based broadleaf herbicide is used.
If the goal is to grow malt barley, then the recommendation is that, due to the risk of a high protein content in the barley, barley should not directly follow
Peas in the rotation. Since wheat receives a premium for protein, it should be grown after peas to take advantage of any extra available nitrogen. However, there are many producers who do grow malt barley varieties following peas and have no problem with excess protein. Weigh your risks and then make your choice.
A number of herbicides have residual activity that can seriously harm these two crops. Some herbicides carry a one year wait after application before growing either of these crops while others recommend a 2 year interval. READ the LABEL! And keep records of your herbicide application.
Yes but there should be at least a 10 day interval between the harvesting of the spring wheat crop and seeding the winter wheat to avoid an infection of wheat streak mosaic virus in the winter wheat. As well, as with all cereals, the crop residue needs to be spread evenly across the field in order to ensure even germination of the winter wheat crop. For more information, consult the Winter Cereals Production Manual available at Ducks Unlimited Canada offices. At time of writing (Oct. 02), Winter Cereals Canada is developing its web site. When it is operational, go to www.wintercereals.com
Well, they can but there will be some effect on yield. The general rule of thumb is that whatever production is achieved through grazing, that amount will be lost in grain yield. Fall and spring conditions, as well as the length of time the livestock are allowed to graze, also impact the net grain yield. Time of flowering and ultimately, harvest readiness may also be delayed if the winter cereal is grazed and then left for grain.
Before seeding winter cereals, know what it is the crop is expected to do. While the plants are able to tolerate some light grazing in fall and early spring, don't expect bumper grain yields.
Good weed control the previous year is essential. Chickpeas need to be seeded into a clean field. There are many products that can be used for grassy weed control on chickpeas but few choices for broadleaf control. Seed treatment is essential on the Kabuli types and is recommended for many of the newer varieties of the Desis as well. Chickpeas need warm soil temperatures to germinate and begin growth. For pulse production information, visit the Saskatchewan Pulse Growers' web site at www.saskpulse.com
Depends on the rate at which the 2,4-D was applied. Late October applications of high rates of 2,4-D such as 12 and 16 oz (active) and 2 oz of Banvel plus 8 oz of 2,4-D could very seriously harm a broadleaf crop. Lighter rates, such as 4 - 6 oz 2,4-D (active) for winter annual control are not usually harmful to canola and peas if there is good soil moisture, warm temperatures early in the spring and there is clay in the soil. Lentils are quite sensitive to 2,4-D residues.
It's not recommended that the 2 crops be seeded in rotation as the seeds of the two are inseparable.
Dr. Brian McConkey of the Semi-arid Prairie Agriculture Research Centre (SPARC) has done extensive research on rotations in southwestern Saskatchewan. His presentation on designing a cropping system-based on crop water use intensity can be found in the SSCA's 2002 Annual Conference Proceedings. SPARC's web site is www.res2.agr.ca/swiftcurrent
Dr. Dwayne Beck of the Dakota Lakes Research Farm at Pierre, South Dakota also has some interesting research on crop rotations. The website there is www.dakotalakes.com
Some examples of Crop Rotations in various Soil Zones:
Dark Brown/Brown Soil Zones
Durum-Winter Wheat-Lentils-HRS Wheat-Mustard
Moist Dark Brown/Black Soil Zones
Barley-Winter Wheat-Peas-HRS Wheat-Canola
Short Forage Rotation
Mustard-Barley-Flax-Cereal underseeded to Sweet Clover-Sweet Clover-Winter Wheat
Longer Forage Rotation
Canola-Pulse-Flax-Cereal-Smart Canola underseeded to Alfalfa-Alfalfa for 3 years-Cereal-Cereal
Saskatchewan Agriculture & Food and Rural Revitalization (SAFRR) has available a software program entitled Land Use Planner that allows producers to plan rotations for up to eight years into the future. The program is available from all SAFRR Rural Service Centres. For more information on the Land Use Planner, visit SAFRR's web site @ www.agr.gov.sk.ca./
Manitoba Agriculture has a Crop Rotation Chart that highlights potential problems and things to avoid when growing crops in succession. Contact a Manitoba Agriculture & Food to obtain a chart. Manitoba's web site is www.gov.mb.ca/agriculture/