25 farming practices that reduce greenhouse gas emissions.

25 farming practices that reduce greenhouse gas emissions.
McKinsey issue report on farming technologies that could reduce agricultural emissions by 20% by 2050.
  • 15 of the 25 are cost saving or cost neutral approaches.
  • The top 15 by abatement potential (tons CO2) account for 85% of the gains.
  • Some of the main challenges to adoption are capital constraints, breaking traditions and limited access to technology
RCS - Introduction to ruminant nutrition

The agriculture sector accounts for around 25% of global greenhouse gas emissions and is coming under increasing pressure to continue to take positive action towards reducing its environmental impact. Changing the way we produce, distribute and consume food worldwide is high on the agenda of Governments and corporations worldwide. Global consulting firm McKinsey have compiled a report based on a decade of research and modelling that has identified 25 proven technologies that can contribute to reduction of agricultural emissions.

Most scientific reports are by nature reductionist and there isn't a huge body of research around more holistic regenerative agriculture approaches or combinations of approaches. Hence the science is somewhat limited from a holistic and whole-farm-ecosystem perspective. Take note that the production systems in question are decidedly 'conventional' from the source list showing that this report is very firmly focused on current dominant food production methods. This is starkly observable in the negative picture this document paints of livestock production, obviously it is not referring to regenerative systems because they account for a small portion of overall livestock production. Nonetheless there are some great lessons to be learnt from this report.

“The first step in reducing emissions from agriculture is to produce food as efficiently as possible—that is, to change how we farm. A set of proven GHG-efficient farming technologies and practices—some of which are already being deployed—could achieve about 20 percent of the sector’s required emissions reduction by 2050”. - McKinsey

These technologies are divided into four focus areas of cropping, protein, rice and energy usage and are compared using a Marginal Abatement Cost Curve (MACC). This MACC, is essentially a way of ranking practices according to the potential volume of emission-reductions, compared to the financial costs or savings associated with making these changes. Basically items on the curve that are in the negative values on the vertical axis mean that implementation of these practices will save money, those in the positive values are a net cost. The larger the width of the column, the greater the potential to reduce emissions. It gives farmers and policy makers a way to compare and decide on which practices to prioritise.

Here they are ranked in priority order of lowest estimated cost (or saving) of GHG abatement: The unit shown is US Dollars per ton of Carbon Dioxide equivalent. ($/tCO2e).

  1. Zero-emissions on-farm machinery and equipment –229
  2. Variable rate fertilization –176
  3. Reduced N over-application in China and India –97
  4. Dry direct seeding –41
  5. Low- or no- tillage –41
  6. Improved equipment maintenance –34
  7. Improved fuel efficiency of fishing vehicles –12
  8. Improved rice paddy water management –12
  9. Improved rice straw management –8
  10. Improved animal health monitoring and illness prevention –5
  11. Feed-grain processing for improved digestibility -3
  12. GHG-focused breeding and genetic selection 0
  13. Livestock nutrient use efficiency 0
  14. Optimal rice varietal selection 0
  15. Nitrogen fixing rotations 0
  16. Improved fertilization of rice 3
  17. N-inhibitors on pasture 15
  18. Improved fertilization timing 40
  19. Controlled-release and stabilized fertilizers 65
  20. Animal feed additives 88
  21. Anaerobic manure digestion 92
  22. Technologies that increase livestock production efficiencies 119
  23. Animal feed mix optimization 131
  24. Conversion from flood to drip or sprinkler irrigation 147
  25. Specialty crop nutrition amendments 523

Here we explain in more detail the top 15 abatement solutions from a Tons of CO2 perspective. This list is how it looks when you instead categorise the actions in terms of their total potential for carbon dioxide equivalent abatement (rather than cost).

  • Adopt zero-emissions on farm machinery & equipment: By 2050 internal combustion engines may well be a thing of the past; with the reality of battery electric powered farm machinery being viable by 2030! An average machinery lifetime of twenty years is the biggest “no-go”; but could be counteracted by revised emission policies.
  • GHG-focussed breeding & genetic selection: Methane efficiency can be bred into herds making a 20% difference – reducing emissions by 5% per head. Sounds small - but measures out to 42 kilograms of methane produced per cow instead of 53 kilograms.
  • Improved fertilization of rice: Water logged rice paddies present the ideal conditions for bacterial production of methane. By using sulphate type fertilisers (to counteract this chemistry) methane emissions can be lowered by 40%. To be successful this measure probably needs to be subsidised as currently only 1% of global production utilises sulphates.
  • Improved animal health monitoring & illness prevention: The fewer animals required to meet the world’s protein demands the better-so they need to be disease-free & healthy. The greatest factor for success with this measure is to make animal vaccines more available for emerging diseases (EG: African- Swine fever).
  • Animal feed mix optimization: Transitioning ruminants to a higher fat diet in their dry feed (with additional plant oils up to 6DM percent) from the traditional 1.5-3DM percent fat –has been clearly linked to suppressing methane production. This shift will be challenging as the profitability lies in creating a cleaner world.
  • Animal feed additives: A potential 15% reduction in ruminant CO2 emissions could be achieved by introducing a class of free acids or salts (sodium fumarate- or acrylate) into the stock feed. This can inhibit methane production by 13% -30% whilst also improving productivity by 2.5%. For feed-lot cattle this is a real possibility, but could raise animal welfare issues.
  • Improved rice-paddy water management: Continuous flooding is the normal practice –but moving to a wetting then drying & single season drainage, can increase CO2 emissions BUT with the greater green benefit of reducing direct methane emissions. Irrigation rates are the biggest deterrent in adopting this practice; allowing also for the fact that rice is mainly grown where seasonal rainfall is high & land is not always level.
  • Anaerobic manure digestion: Capturing and generating biogas (bio-methane) to use on the farm or be sold back to the grid is a real potential, especially for dairy or pig farmers. Large-scale operations in Europe & North America use industrial mix, covered lagoon and plug-flow digesters; but the smaller more affordable “dome digesters are available.
  • Feed grain processing for improved digestibility: Steam flaking of grain improves starch digestibility by reducing the surface area, and increasing protein input as stock feeding effort is reduced. Capital expenditure for plant cost is the main constraint, but with forward thinking public financing programs this measure could reduce methane emissions by 15% per head of stock.
  • Dry direct seeding: Replacing nursery produced rice seedlings by direct sowing into a dry soil - can save a month of water and limit activity of methane producing microorganisms; cutting emissions by 45% per hectare! Cost savings are made by the resulting reduction in labour. Local advisory networks would be key to the implementation with education on optimal rice varieties.
  • Technologies that increase livestock production efficiencies: Use of probiotics, hormones, microbial additives, bio security methodology, herd management & digital monitoring are all examples of technological options available to the meat industry. Antibiotic “alternative growth promoters” have also been developed for use on commercial farms as a much more viable option to improving protein growth.
  • Nitrogen inhibitors on pasture: Mitigating the ammonia produced by cattle and cows urine is possible by applying dicyandiamide or nitropyrene alongside urease inhibitors. This is most effective where pasture intensity is highest.
  • Low or no-tillage: Conservation of soil organic matter, water and limiting erosion by shallow plowing, chisel drilling and fewer tillage passes has shown to reduce fuel usage up to 75% in most climates. Long term savings outweigh the yield loss balanced out by less field labour costs.
  • Reduced Nitrogen application in China & India: The overuse of nitrogen fertilisers to the value of $13 billion occurs annually in the world, and especially in the countries where it is heavily subsidised. A calculated 24% reduction in emissions could be achieved if farmers were educated to apply less.
  • Controlled release & stabilised fertilisers: Replacing the traditional water soluble quick release fertilizers, with a less linear type product, ensures the plants get the nitrogen when they actually need it; resulting in less nitrogen lost to the environment. Driving this measure is a tricky one as the product is expensive –perhaps the exploration of perennial row crops would be a more sustainable approach?

Globally one in four people are farmers and the sector is hugely diverse, creating big challenges in taking these practices into wide spread adoption. Especially considering that three out of four farms in the world are small holdings of “less than three soccer fields”- meaning that practice changes and technology will need to diffuse to smallholder farmers. Balancing out the high level of scientific content in this report is the sobering knowledge that one-third of all food produced in the world - is wasted, which clearly needs to be a big part of the solution to improving efficiency in relation to emissions.

Glancing down this list you can probably tick-off the measures you are achieving already, but there may well be some potential farm practices worth exploring further. As key players in balancing future food security with livelihoods, this report is vital for the “here and now” Farmers and future generations. You will need a large coffee or tea pot–if you click on the full report and go through all 25 in detail, but it's well worth it.

 North America
 Carbon Farming
#greenhouse gas
#climate change

A version of this article was originally published on the site Regen Farming News on Wednesday, May 6, 2020.



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