Crop production is heavily dependent on weather and climate. Changes in climate can affect crop production both positively and negatively. Practices and technology are helping farmers mitigate and adapt to changing climates.
Farmers are already taking important steps by adopting climate smart agriculture practices to lower their greenhouse gas (GHG) footprint. National GHG emissions are reported annually by sector and province in the National Inventory Report on Greenhouse Gas Sources and Sinks in Canada (2019).
GHG sources and sinks
There are many opportunities for crop producers to remove, reduce or replace GHGs while gaining the benefits of climate smart agriculture (see Figure 1).
- About 30% of GHG emissions are nitrous oxide (N2O) from fertilizer, manure, tilled soil, crop residues and compost. These are affected by soil, moisture, and temperature conditions and application method.
- Another 20% of GHG emissions are carbon dioxide (CO2) from fossil fuel use, tillage, fertilizer application and decomposing soil organic matter. These are affected by tillage intensity and the number of equipment passes.
Agricultural soils act as important carbon sinks by storing carbon that plants create during photosynthesis.
Figure 1: Agricultural GHG management
Agricultural GHG management
Alberta’s cool dry climate is very well suited to increasing rates of soil carbon storage through removal of CO2 from the atmosphere by growing crops. Related benefits of improved water infiltration and enhanced nutrient cycling also increase the capacity of soils to adapt to changing climates.
Conservation tillage – Increases soil carbon storage by no-till, direct seeding or reduced tillage. At the same time, this decreases fuel use, costs, N2O emissions, and soil and nutrient losses from erosion by water or wind.
Perennials – Including perennial crops in an annual rotation improves soil carbon storage and nutrient uptake, due to deeper rooting and less soil disturbance. Crop rotations that include perennials also help reduce risks of disease, insects, pests, weeds and erosion.
Cover crops – Seeding cover crops into annual crops or following annual crops uses excess nutrients and takes advantage of spring moisture. Benefits include increased soil carbon, and protection from soil erosion by water and wind after annual crop harvest. Care is needed in drier areas where there may be competition with the following crop for soil moisture.
Other practices – Lowering GHGs by increasing soil carbon storage can result from converting marginal cropland to perennial crops or woody biomass, and by reducing areas of summerfallow. Biomass from woodlots and inter-planting with crops and pastures can also provide value for renewable energy.
Lowering GHGs from cropping systems is about matching nutrients with crop needs – 4R Nutrient Stewardship: right timing, right placement, right product and rate of nutrient source. A focus on optimizing inputs also saves costs while helping to identify effective responses to a range of climatic conditions.
Further efficiency and improvements result from the use of technologies and tools:
- Soil sampling is key to knowing what levels of nutrients are in a soil and if there are any limitations to crop growth. For more information on soil sampling go to Chapter 3.3, page 87 of the Nutrient Management Planning Guide.
- Time nutrient application as close as possible to maximize crop uptake.
- To increase nutrient availability and avoid losses, band commercial fertilizers to the side of the seed row rather than broadcast. Incorporate (solid) or inject (liquid) manure.
- The Alberta Farm Fertilizer Information and Recommendation Manager (AFFIRM) is a free on-line tool that links soil test results, crop type, nutrient contents of fertilizer and or manure and yield goals with economic considerations.
- Alberta’s Manure Management Planner is a free on-line tool that shows how to balance manure sample test results with crop needs.
Biofuels made from Alberta-grown canola help lower fossil fuel emissions. Planting shelterbelts and woodlots on marginal cropland stores carbon with the potential for extra income from the biomass used for renewable energy. Roots of woody biomass crops also help stabilize soils in erosion prone areas, increasing resilience to extreme climatic conditions.
Cropping practices to mitigate greenhouse gases (PDF, 391 KB)
Practices for improvement
Table 1 gives examples of practices that influence each type of agricultural GHG, along with associated challenges and opportunities. In addition to gains in efficiency and climate resiliency associated with lowering GHGs, programs are available to help with improvements. For more information on possible programs, see Sustainable Canadian Agricultural Partnership.
Table 1. Ways to lower carbon footprints while increasing efficiencies and climate resiliency in crop production.
|Practice||Reduce Nitrous Oxide||Reduce Carbon Dioxide||Increase Carbon Storage||Challenges||Other Benefits|
|Reduce Emissions - Nutrient Management|
|Increase nitrogen fertilizer use efficiency by optimizing timing, rate, placement and product||considerable||Soil sampling costs, logistics in spring seeding, timing, labour||Higher yields, fuel and labour savings, degreased nutrient losses, potential sales of carbon offsets*|
|Apply manure to unmanured soils||minimal||minimal||Transportation costs||Improved soil water holding capacity and nutrient cycling, fertilizer savings|
|Remove Emissions – Increase Carbon Sequestration|
|Conservation cropping||minimal||minimal||minimal||Specialized equipment, crop residue management||Fuel and labour savings, improved soil quality, potential carbon offsets*|
|Reduce or eliminate summerfallow||minimal||minimal||moderate||Wet spring conditions||Fuel savings, potential carbon offsets*|
|Increase perennials in annual rotations||minimal||minimal||moderate||Lower returns||Some fuel and fertilizer savings|
|Convert marginal annual cropland to perennials||minimal||minimal||moderate||Lower returns||Fuel savings|
|Cover crops||minimal||Additional costs, possible moisture competition in drier regions||Provides protection from wind and water erosion|
|Plant windbreaks, woodlots, agroforestry||considerable||Monitor to manage weeds, potential obstacles to field operations||Saves costs of inputs on marginal lands, protection from wind and water erosion|
|Replace Emissions – Renewable Energy|
|Biofuels||minimal||Equipment retrofit||Reduce farm waste, fuel savings, potential for carbon offsets*|
|Biomass||minimal||Inconsistent supply, capital cost recovery||Potential for income of the biomass, potential for carbon offsets*|
* Carbon offsets may be available with verifiable records to document practice improvement, see Agricultural Carbon Offsets.
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