How do I reduce

Published: July 17, 2019

Tagged with:

  • Overview
  • Climate change
  • Emissions estimates
  • Farm emissions reduction
  • Greenhouse gases

There is no one-size-fits-all solution, but many New Zealand farmers and growers have already achieved great results. Below are some steps you could consider for your farm.

How to reduce emissions


Duration: 3:03

Farmers have been asking: what can I do to reduce emissions on my farm? Well, there are three gases we need to reduce: carbon dioxide, nitrous oxide, and methane. But on-farm, it’s particularly about the last two. Lots of small steps can add up to make a big difference.

The good news is that combined greenhouse gas emissions from New Zealand agriculture are no longer going up, thanks to farmers’ efforts to become more and more productive and efficient over the years. As a result, the greenhouse gases emitted per unit of product are going down.

Without all this great work, emissions from agriculture in New Zealand would be about 30 percent higher than now, to produce the same amount of food.

[But there’s a lot more of us now.]

[And a lot fewer of us!]

But we need to reduce emissions, not just keep them steady. There’s no magical formula here, but there are several things that can be done on farms right now – and some will have other benefits too.

You know your business better than anyone, so you’re in the best place to work out which of these are achievable.

Here’s what some farmers are doing already, that you might want to consider for your farm.

First, find out what your farm’s greenhouse gas emissions are and include them in your planning. Depending on the farm, it might be that some of those options can save you time, and money.

In a nutshell, methane emissions are related to the total amount of dry matter eaten. Nitrous oxide emissions depend on the total amount of nitrogen going through your farm via feed and fertiliser. So, what steps can be taken to change these quantities, while still running a profitable business?

Look carefully at the feeds used. Can you use feeds with lower nitrogen or higher energy content to get animals to market quicker? Would a less-intensive system work for you? It might be reducing fertiliser inputs and stocking rates, changing the ratio of your stock type, or once-a-day milking.

You could try using precision technologies for improving the amount and timing of your fertiliser application.

Look at the balance between individual animal performance and stocking rate. Could you run slightly fewer animals and focus more on getting the most out of each animal to keep production up?

You could also consider the balance of your land use to reduce livestock emissions. Many farmers are now integrating trees onto their less productive land, and there is Government support to help do this.

For some farms, diversifying some of the land use to cropping or horticulture could reduce overall emissions and dependence on one income stream.

Rest assured, you’re not alone in your efforts. Scientists are working hard on new solutions, with some very promising results. Some of them are being trialled already. In the future, it’s likely we’ll be able to breed low-methane animals or use inhibitors and vaccinations to reduce the amount of methane that animals belch out.

We’re all working towards the same goal, and any small step is a step in the right direction.

Remember to check out our website for lots more information. Thanks for watching.

Produced by the New Zealand Agricultural Greenhouse Gas Research Centre. Funded by the New Zealand Government

How can I find out my farm’s greenhouse gas emissions?

Knowing what your greenhouse gas emissions are is the critical first step towards planning for reductions. A recent survey found that only 2% of New Zealand farmers know what their emissions are.

There are several tools for estimating greenhouse gas emissions on New Zealand farms. These vary in complexity and cost, and improvements to their accuracy, usability and sensitivity are ongoing.

Lincoln University’s carbon calculator is an example of a simple tool that gives farmers a quick estimate of their emissions.

OVERSEER is an example of a more complex calculator that estimates methane and nitrous oxide emissions at the farm level, consistent with New Zealand’s Greenhouse Gas Inventory.

In the future, farmers may be asked to include greenhouse gas emissions estimates in their farm environment plan. An environment plan outlines environmental risks and risk-management options specific to a property. It reflects the local climate and soil types, the unique farming operation, and the goals and aspirations of the land owners and managers.

Information on farm environment plans is available on industry websites:

Work is underway to assess what support farmers would need if farm environment plans were to include a greenhouse gas component.

Can we get there through efficiency gains?

The good news is that absolute greenhouse gas emissions from New Zealand agriculture peaked in 2005, thanks to farmers’ ongoing efforts to become more productive and efficient. Since 1990, efficiency gains have seen greenhouse gas emissions per unit of milk or meat produced (‘emissions intensity’) reduce by approximately 1% per year per unit of production.

Without this great work, New Zealand’s agricultural emissions would be about 30% higher than now to produce the same amount of food.

However, reducing emissions intensity on its own does not guarantee a reduction in total emissions. As an example, the dairy sector has reduced its emissions intensity, but this has been more than offset by increased production, leading to an increase in total emissions. By contrast, New Zealand’s lamb production is similar to 1990 levels, but enteric methane emissions have fallen by 41% over the same period.

Although there is not yet a silver bullet to significantly reduce methane (see future options), modelling studies suggest that it may be possible to reduce a farm’s total greenhouse gas emissions by up to 10% by fine-tuning production systems and including greenhouse gas emissions in farm planning (some of those options are discussed here). This may not seem like much, but lots of small steps can add up to make a big difference.

What options are available to farmers now?

Options to reduce emissions from pasture-based livestock production exist, but there are limits to the size of the reductions that can be achieved without significantly affecting profitability. There are three broad areas:

  • Improving the productivity and efficiency of farm systems
  • Reducing emissions by changing feed
  • Reducing the amount of feed eating by reducing livestock numbers

Note that emissions vary widely across New Zealand farms. Much variation is due to factors such as climatic and soil conditions. However, the way the farm is managed is also important.

Reducing stocking rate and increasing per-animal performance so that total production levels are maintained is one avenue to explore. This can reduce emissions because less food is needed to produce the same amount of milk or meat.

Modelling by the Biological Emissions Reference Group estimates that lower stocking rates and improved individual animal performance can, in some circumstances, reduce emissions by up to 10% on dairy farms and by 2-5% on sheep and beef farms, while maintaining production and improving profits.

A ewe and twin lambsIncreasing the reproductive performance of the herd to allow for reduced replacement rates can decrease emissions, as less feed is needed for young stock. For more on this in dairy systems, see here.

Reducing nitrous oxide emissions relies on having less nitrogen deposited onto paddocks. This comes mainly from dung and urine deposited by animals, but some also arises from fertiliser applications.

Reducing fertiliser applications can help reduce nitrous oxide emissions. More information on nitrous oxide, and ways to reduce it, will be provided on this website soon (sign up here to receive updates).

It may also be possible to reduce nitrous oxide emissions (and the amount of nitrogen leached) by replacing high-nitrogen feeds with feeds that have a lower nitrogen content. Examples are maize silage and fodder beet. See more in this factsheet on feeds from the New Zealand Agricultural Greenhouse Gas Research Centre (NZAGRC) and the Pastoral Greenhouse Gas Research Consortium (PGgRC).

Modelling has shown that, in some circumstances, once-a-day milking and reducing total milk production could reduce total production and emissions by 6-7% without affecting profitability. In this option, lower labour costs would need to balance a reduction in total milk income. Find more information on once-a-day milking here.

A field of barleyDiversifying some land away from livestock production and into less greenhouse gas-intensive systems (e.g. into arable crops or horticulture) may be an option for some farmers. Tree-planting can also assist. See here for more information.

These options add up to small reductions in total agricultural greenhouse gas emissions. However, the less greenhouse gases emitted, the better for the climate.

Actions you take now might have other benefits too. Running an even more efficient and productive system with lower inputs might also enable you to meet water quality regulations and improve economic performance. You know your business better than anyone, so will be in the best place to work out which are achievable and sustainable under your business plan.

Bigger reductions may be achieved in the future through emerging technologies such as methane vaccines and inhibitors. For more on future options, see here.

For more information on reducing greenhouse gas emissions at the farm level:

Trees for offsetting emissions

Planting trees on less productive land might be an effective way to reduce non-carbon dioxide emissions from your farm. Growing trees absorb and store carbon. However, the rules around trees and greenhouse gases are complex (and subject to change) and we recommend you obtain advice from a forestry expert before considering this option.

For more information:

Why doesn’t pasture count as an offset?

Grass removes carbon dioxide from the atmosphere as it grows and returns this to the atmosphere when it is harvested. Trees do the same thing. The difference is that grass is harvested after an interval of just weeks, while trees are harvested after decades – or not at all.

This means that trees accumulate carbon year on year, but grass doesn’t. The same quantity of carbon is stored in grass at the start and end of each year.

Why isn’t soil carbon counted?

Hands holding a soil sampleCarbon in soil is bound up as organic matter and is typically greatest in the topsoil. Large amounts of carbon enter the soil from decaying plant material but most of this carbon is quickly lost back to the atmosphere via respiration.

Carbon stocks are high under New Zealand pastoral soils, for two reasons:

  • Our soils have generally been well-managed with little intensive cropping, a practice that has decreased soil carbon in other countries.
  • Our soils have a large capacity to protect and keep carbon, and we have a temperate climate that mostly supports year-round plant growth.

The main question from a greenhouse gas perspective is whether these carbon stocks are changing. Broadly, on flat land, soil carbon content has not changed in the last two to three decades, except for organic or peat soils. There is some evidence that hill country soils have gained a small amount of carbon, but it is not clear how widely spread these gains might be.

Research is underway to get a clearer picture of soil carbon stock change in New Zealand and the impact of different management practices. However, until this evidence emerges, it is unlikely that soil carbon will be counted as an offset.

See more on New Zealand’s soil carbon research here and here.

What technologies might be available for farms in the future?

A significant research programme has been underway in New Zealand since the early 2000s, exploring new options for reducing total on-farm emissions.

The complexity of agricultural greenhouse gas emissions and their interplay within a farm system means that this has been a slow journey. However, promising options are on the horizon.

Breeding low-emitting sheep and cattle 

Low emitting sheepSome animals emit less methane than others, and it has been confirmed that this is a genetic trait. Good progress has been made in the sheep breeding programme with incorporation into selection indices likely during the early 2020s. Work on breeding low-emitting cattle is just beginning. Methane has been the target to date, but it may also be possible to breed animals that excrete less nitrogen. For the science, see here.

For more information, see this Newsroom article published on 21 November 2019.

Low emissions feeds

Although the primary driver for methane emissions is the quantity of feed eaten, the chemical make-up of feeds can have an influence. Different feeds can also influence the quantity of nitrogen deposited in urine and the chemical make-up of the urine. Forage rape can reduce methane emissions by up to 30% and plantain has been shown to reduce nitrogen leaching and nitrous oxide emissions. Fodder beet has also shown promising results although the overall benefits and applicability of these alternative fodder crops will depend on specific farm systems, including when the feeds are being used. For the science, see here and here (methane) and here (nitrous oxide).

Methane inhibitors

Rumen samples

Rumen samples © Veronika Meduna

A methane inhibitor is a chemical compound fed to an animal to reduce the activity of the microorganisms that produce methane. It is highly likely that an inhibitor will be on the market by 2023. Usually an inhibitor has to be fed daily, which makes it unsuitable for many of New Zealand’s grazing-based systems. However, the development of slow-release formulations could change this. For the science, see here and here.

Methane vaccine

A methane vaccine would, in theory, trigger an animal’s immune system to generate antibodies in saliva that reduces methane in a similar way to an inhibitor. A vaccine would be ideal for New Zealand’s pasture-based systems, but its successful development is extremely challenging. For the science, see here.

Nitrification inhibitors 

Nitrification and urease inhibitors are chemical compounds that are intended to slow down the microbial conversion of nitrogen contained in fertilisers (urea) or animal excreta into nitrate and nitrous oxide. Such inhibitors can be added to fertiliser or deposited directly onto grazed pasture. For the science, see here.

For more information on future options:

Published: July 17, 2019