Effectiveness of Best Management Cropping Systems to Abate Greenhouse Gas Emissions

Best management practices (BMPs) for cropping systems that involve conservation tillage and nutrient management are proposed as potential win-win solutions for both farmers and the environment. While originally targeted as a means for improving soil and water quality, these BMPs may also contribute to the mitigation of greenhouse gases (GHGs). Mitigation efforts have focused primarily on the ability of BMPs to sequester carbon and the subsequent potential revenue source carbon sequestration may represent to farmers. Increasingly, evidence from experimental stations calls into question the potential for C-sequestration with reduced tillage in soils in Eastern Canada. However, there are other ways in which BMPs can reduce GHG emissions: lowering fuel and nitrogen fertilizer consumption and, potentially, lowering emissions of nitrous oxide from the soil. This article examines the profitability and emission reduction potential of best management cropping practices for Ontario.Agricultural and Food Policy, Farm Management,

Methane and nitrous oxide emissions from Canadian dairy farms and mitigation options: An updated review

This review examined methane (CH4) and nitrous oxide (N2O) mitigation strategies for Canadian dairy farms. The primary focus was research conducted in Canada and cold climatic regions with similar dairy systems. Meta-analyses were conducted to assess the impact of a given strategy when sufficient data were available. Results indicated that options to reduce enteric CH4 from dairy cows were increasing the dietary starch content and dietary lipid supplementation. Replacing barley or alfalfa silage with corn silage with higher starch content decreased enteric CH4 per unit of milk by 6%. Increasing dietary lipids from 3% to 6% of dry matter (DM) reduced enteric CH4 yield by 9%. Strategies such as nitrate supplementation and 3-nitrooxypropanol additive indicated potential for reducing enteric CH4 by about 30% but require extensive research on toxicology and consumer acceptance. Strategies to reduce emissions from manure are anaerobic digestion, composting, solid-liquid separation, covering slurry storage and flaring CH4, and reducing methanogen inoculum by complete emptying of slurry storage at spring application. These strategies have potential to reduce emissions from manure by up to 50%. An integrated approach of combining strategies through diet and manure management is necessary for significant GHG mitigation and lowering carbon footprint of milk produced in Canada

Effectiveness of Best Management Cropping Systems to Abate Greenhouse Gas Emissions

Best management practices (BMPs) for cropping systems that involve conservation tillage and nutrient management are proposed as potential win-win solutions for both farmers and the environment. While originally targeted as a means for improving soil and water quality, these BMPs may also contribute to the mitigation of greenhouse gases (GHGs). Mitigation efforts have focused primarily on the ability of BMPs to sequester carbon and the subsequent potential revenue source carbon sequestration may represent to farmers. Increasingly, evidence from experimental stations calls into question the potential for C-sequestration with reduced tillage in soils in Eastern Canada. However, there are other ways in which BMPs can reduce GHG emissions: lowering fuel and nitrogen fertilizer consumption and, potentially, lowering emissions of nitrous oxide from the soil. This article examines the profitability and emission reduction potential of best management cropping practices for Ontario

Long-term variability in N2O emissions and emission factors for corn and soybeans induced by weather and management at a cold climate site

Publication history: Accepted - 24 December 2021; Published online - 31 December 2021.Nitrous oxide (N2O) emissions are highly variable in space and time due to the complex interplay between soil, management practices and weather conditions. Micrometeorological techniques integrate emissions over large areas at high temporal resolution. This allows identification of causes of intra- and inter-annual variability of N2O emissions and development of robust emission factors (EF). Here, we investigated factors responsible for variability in N2Oemissions during growing and non-growing seasons of corn and soybeans grown in an imperfectly drained silt loam soil, in Ontario, Canada. We used quasi-continuously (at half-hourly to hourly intervals) N2O fluxes measured via the fluxgradient technique over 11 years for corn and 5 years for soybeans and evaluated the uncertainty of default IPCC and Canada-specific EFs. In the growing season, emissions were controlled by soil nitrate content, soil moisture and temperature in the fertilized corn, while moisture and temperature regulated N2O emissions in the unfertilized soybeans. In the non-growing season, nitrogen (N) input from the crop residue did not affect the emissions, pointing to freeze-thaw cycles as mechanisms for enhanced N2O emissions. The non-growing season contribution to annual emissions was 38%in corn and 43% in soybeans. On average, annual emissions were 2.6-fold higher in corn than soybeans. Observed mean N2O EFs were 0.84% (0.12–2.02%) for growing season and 1.69% (0.29–7.32%) for yearly emissions. The growing season EF derived from long-term N2O emissions was 0.9 ± 0.14%. The interannual variability in N2O emissions and EFs can be attributed to management practices and annual weather variability. The default IPCC approach based on overall N input had poorer performance in predicting annual N2O emissions compared to the current Canadian methodology, which includes management and environmental factor in addition to N inputs. The observed emissions were further evaluated with a newly developed growing season N2O emission prediction approach for Canada. However, performance of the approach was poorer than IPCC or the current national Canadian approach. Additional tests of the new national methodology are recommended as well as consideration of non-growing season emissions.Funding for this research was provided Canada's Natural Sciences and Engineering Research Council Discovery and Strategic Grants Program (project STPGP 494224-16), the Ontario Ministry of Agriculture, Food and Rural Affairs through its Ontario Agri-Food Innovation Alliance program and the NSERC CREATE Climate-Smart Soils program

Greenhouse gas emissions and offset potential from sugarcane straw for bioenergy production in Brazil

This study aims to assess the additional Greenhouse gas (GHG) emissions affected by straw removal from the soil surface in sugarcane areas, including measurement of short-term soil CO2-C emissions plus emissions associated with the recovery and transport operations of straw bales until to the industry gate (diesel emissions) and estimated soil N2O emission, comparing with leaving all straw on the soil surface. Taking into account the main sources evaluated (soil CO2, diesel and N2O from straw), the total additional GHG emissions from the recovery of 6.9 Mg Dry Matter ha-1 (27%) was estimated at 1423 kg CO2eq ha-1, resulting in a carbon footprint of 206.2 kg CO2eq per megagram (Mg) of straw recovered. Applying the parameters cited in this study for electricity generation (GHG emission and offset potential), our results showed an additional GHG emission of (+) 860 kg CO2eq ha-1. Applying the same parameters for second generation (2G) ethanol production replacing gasoline, an avoided GHG emission of (-) 2316 kg CO2eq ha-1 could be achieved. The route of recovering 27% of sugarcane straw from the soil surface through bale system for bioelectricity production using the technical parameters and industrial efficiency rate of this case study resulted in a C footprint of 347 kg CO2eq MWh-1. Improving the efficiency rate for straw conversion in bioelectricity based on its lower heating value could reduce its C footprint to 62.26 kg CO2eq MWh-1 produced. For sugarcane straw recovery at the first cutting cycle in clay soil, the option of producing ethanol 2G could offset GHG emissions once replacing fossil gasoline, resulting in a C footprint of 0.86 kg CO2eq L-1 of 2G ethanol in the agricultural phase, an option to contribute to better sustainability of sugarcane straw recovery, supporting renewable and sustainable bioenergy systems, and reducing the impacts of Global Climate Change

Natural climate solutions for Canda

Alongside the steep reductions needed in fossil fuel emissions, natural climate solutions (NCS) represent readily deployable options that can contribute to Canada’s goals for emission reductions. We estimate the mitigation potential of 24 NCS related to the protection, management, and restoration of natural systems that can also deliver numerous co-benefits, such as enhanced soil productivity, clean air and water, and biodiversity conservation. NCS can provide up to 78.2 (41.0 to 115.1) Tg CO2e/year (95% CI) of mitigation annually in 2030 and 394.4 (173.2 to 612.4) Tg CO2e cumulatively between 2021 and 2030, with 34% available at ≤CAD 50/Mg CO2e. Avoided conversion of grassland, avoided peatland disturbance, cover crops, and improved forest management offer the largest mitigation opportunities. The mitigation identified here represents an important potential contribution to the Paris Agreement, such that NCS combined with existing mitigation plans could help Canada to meet or exceed its climate goals