My first 13 years of farming saw endless lorry-loads of fertilisers and chemicals coming on to the farm. The controls on their usage, and the consequential problems, were evidently increasing. I re-examined what I was doing and who the gainers and losers were.

Conclusion: I needed to cut down the inputs, improve sustainability, stay friends with the consumer and re-enliven my soils.

We all want to produce sufficient food to supply the full nutritional requirements of the human species, whilst attempting to live in harmony with the natural environment and its finite resources. Simple… except it’s not.

Livestock farmers appreciate that every farm has a maximum stocking rate, beyond which animals will be underfed without importing food. We need to reduce the numbers of animals farmed, because the supplies of grain and proteins are going to become pressurised by the reducing quantities of available fertilisers, oil and other inputs.

We need to appreciate the finite nature of natural key resources upon which agriculture depends. Oil, phosphate fertiliser and access to fresh water being the principal inputs. The use of ‘fossil’ water reserves illustrates the problem, and whilst it’s not a problem in the rainy UK, it is in many countries from which we import food, often to feed livestock – as seen in the staggering scale of imported GM soya from Brazil to feed British cows for example.

Farmers are the largest consumers of these resources. With what responsible logic can we justify feeding livestock tonnages of grains and proteins? As Simon Fairlie has described on this blog and in his book Meat: A Benign Extravagance, it’s a horribly inefficient way to produce food. If only we could stand back and assess it logically and not feel threatened by our own, as farmers, vested interest. 

Big problems

Why not embrace the findings of the International Assessment of Agricultural Knowledge, Science and Technology for Development  which concluded that “business as usual” was not an option? 

Reducing feeding grains and proteins to livestock will save natural resources, and indirectly improve people’s health. Furthermore, huge areas of currently crop-producing land would then grow grass, still to support livestock, enabling preservation of fragile and diminishing soils by minimising soil erosion.

Some may think these policy shifts equate to less food for most people. It may for a few, but it won’t necessarily for the majority. And would that be a bad thing? Astonishing food wastage occurs through over consumption – people becoming fat – also known as the obesity epidemic in politically-correct language. We now have more obese people in the world than hungry, and the vast majority of this is avoidable. When did this become acceptable?

Perhaps these policy shifts would make food more expensive. Then we’d all eat different diets, with less meat, and those over-consuming will necessarily reduce intake. This would also lead to less waste minimisation during food processing and domestically: nobody in 2011 should accept the 18 million tonnes of food waste. Whilst some is unavoidable, a huge amount is careless at best.

By using less land to grow feed for animals, substantial areas of current cropland could be afforested, recreating the lungs of the world, and some land can switch to energy production to be used locally.

Furthermore, these significant changes would dispense with the temptation to tinker with nature’s genetics by utilising GM crops. Other nicely developing breeding techniques, such as marker-assisted breeding, will enhance yields and improved resistance to attack, whilst keeping our customers onside.

Hard solutions

Delivering radical change is difficult. Nobody would suggest otherwise. But we don’t have the choice, and the sooner we start the less Draconian the action will need to be.

If we won’t do this for society, and ultimately for our children’s sake, and continue to prefer prevarication then we drive the car towards a cliff edge. Either we make a reasonably gentle turn now, or continue taking risks, hoping for unknown options for our salvation will appear later.

Are farmers big enough to do this? It will obviously have negative implications for the capital values of many of our businesses. But, do we, as part of a bigger society, have any realistic alternative option?

About Oliver Dowding

After leaving agricultural college in 1976, Oliver returned home to the family farm in South East Somerset, a traditional dairy and arable farm, extending to over 900 acres. 

In 1989 the decision was made to convert the entire farm, including 300 dairy cows and 200 youngstock immediately to organic status, which became the subject for a TV programme. The farming area has subsequently shrunk and the dairy disbanded.

Oliver has been involved with a variety of national agri-political posts and interests, including chairing the NFU organic committee, and as vice-chairman of the leading organic dairy co-operative, OMSCO. 

He is an active journalist and campaigner, particularly on health and environmental issues.

Carbon dioxide is the most commonly recognised enemy in terms of its contribution to greenhouse-gas (GHG) emissions, and certainly the biggest culprit in terms of volume, but there are other gases, closely tied with food production, that are also major targets for reduction.

Farming is responsible for about 8% of the UK’s GHG emissions (up to about 19% when the road to consumption is included) but about 40% of its methane emissions, which mainly come from livestock, and 76% of its nitrous oxide emissions, which are mainly due to fertiliser use.

There is a lot of pressure on agriculture to reduce emissions of these gases because methane is about 20 times and nitrous oxide around 300 times a more powerful GHG than carbon dioxide.

The devil in the details

To address the nitrous oxide (N₂O) problem, a recent event at the Royal Society, ‘Nitrous oxide: the forgotten greenhouse gas’, reviewed our current understanding of the processes by which N₂O can be produced or destroyed and discussed approaches for combating N₂O release.

I work on GHGs too. At Rothamsted Research my group’s work focuses on N₂O, which is mostly produced by two processes in soils carried out by microbes.

First, N₂O is a small but important by–product of a process called nitrification, which is the conversion of ammonium to nitrate. It’s part of a natural cycle and an essential soil process as dead plant and animal material decays and is converted back to the building blocks of new organisms. The second process is denitrification, the conversion of nitrate to nitrite, N₂O and N₂ — the nitrogen gas that forms 78% of the air we breathe. It is also a natural process and happens when oxygen is in short supply, especially when soils are very wet, and produces large but short–lived peaks of N₂O.

The ‘Need for nitrogen’ to make crops grow was also detailed on this blog by Ian Crute. It can come from fertiliser, legumes (biological fixation) or recycled manures, but fossil fuel-based fertiliser nitrogen dominates and is used to produce about half the world’s food. We will need more food and more nitrogen as the population increases toward nine billion, or more.

Unfortunately, some of this nitrogen will end up as N₂O whether it comes from synthetic fertilisers or natural manure. The question is can we help our farmers to be more efficient and get more nitrogen into their cops and less into N₂O?

Working the problem

Obviously we should not (and could not) try and stop natural processes such as nitrification or get rid of the microbes. But we wonder if we could find ways, when the soil is wet and denitrification happens, to encourage the microbes to convert nitrate to dinitrogen (N₂) instead of N₂O, all the time?

We have used our 168–year-old Broadbalk experiment on wheat production at Rothamsted, and a very special laboratory system that enables us to collect and analyse all the gases that come from the soil, to find out what controls the microbes and their production of N₂O.

Our research shows that, perhaps not surprisingly, the amounts of nitrate and carbon (the microbes’ energy source) are very important: they must be in balance. So farmers need to get the right amount of nitrogen to their crops.

The structure of the soil is also important – a soil that holds enough water to supply crops but does not easily become saturated (waterlogged) and so deprive the plant roots of oxygen is important. And we were surprised to see that a soil made wet before it becomes really saturated with water produces less N₂O than one dried before suddenly becoming saturated. It seems that the microbes behave better when accustomed to being wet!

However, if climate change happens as predicted then in the UK we will get more very dry weather followed by sudden wetter periods which our research suggests will increase N₂O production and exacerbate climate change even further.

No laughing matter

Elsewhere at the meeting, Robert Portman brought us the good news that the GHGs methane and carbon dioxide reduce the depletion of ozone. Unfortunately N₂O increases ozone depletion as well as being a very potent GHG, so it’s bad news all round.

Paul Crutzen, the Nobel Prize winner in 1995, and Keith Smith have made some detailed life cycle calculations that reinforce the view that most first generation bioenergy crops, such as wheat and oilseed rape, don’t deliver any fossil fuel saving. But sugar cane does because of the biological nitrogen–fixing microbes associated with sugar cane roots. (Not everyone agrees with this story so there is some good research to be done understanding what is happening.) Second generation bioenergy crops such as willow and Miscanthus) have a good carbon balance, but only if no or very little nitrogen fertiliser is used.

Some long–term opportunities for reducing nitrous oxide emissions were suggested. For example, Liz Baggs and colleagues at the new James Hutton Institute (also a subject of this blog post) have a range of barley varieties that seem to emit different amounts of N₂O.

But, at the moment, as I and Lars Bakken said at the meeting, the best practical options to mitigate N₂O release are managing soil pH and excess nitrogen inputs, and maintaining good soil structure to avoid soils becoming saturated with water and depleted of oxygen.

About Professor Keith Goulding

Professor Keith Goulding joined Rothamsted Research in 1974 after completing a Master’s degree in Soil Chemistry at Reading University and then a PhD in soil chemistry at Imperial College in 1980. He studies how plant foods (nutrients) in soils become available to growing plants and the best ways of augmenting these with fertilisers and manures without polluting air and water. He is a visiting Professor at the University of Nottingham, a Fellow of the Institute of Professional Soil Scientists and a Chartered Scientist. He was awarded the Royal Agricultural Society of England’s (RASE) Research Medal in 2003 for his research into diffuse pollution from agriculture and elected an Honorary Fellow of the RASE in 2010. He received a Nobel Peace Prize certificate for his contribution to the work of the Intergovernmental Panel on Climate Change, for which the Panel and Al Gore were jointly awarded the Prize in 2007. He is currently Vice–President of the British Society of Soil Science.

Plants must secure high levels of nitrogen, and in conventional agriculture nitrogen is added at high concentrations in the form of inorganic fertilisers. Artificial nitrogenous fertilisers can increase yield by as much as 50% and the global farming system, and hence our own food supply, is now dependent on them. We would face very severe food shortages if nitrogen fertilisers were to become unavailable.

However, their use comes with high economic and environmental costs.  Farmers, especially in developing countries, spend a high proportion of their income on fertilisers that account for a significant proportion, sometimes the majority, of the costs of crop production.  Fertiliser synthesis and application leads to high amounts of nitrous pollution in aquatic systems causing algal blooms and dead zones in shallow seas as well as nitrous pollution of the atmosphere causing poor air quality and significant greenhouse gas emissions.

But we cannot stop using fertilisers and meet a food security agenda; nor can we afford to keep using them and meet an environmental sustainability agenda.

Producing nitrogenous fertilisers requires lots of energy that currently comes from the burning of fossil fuels. It is anticipated that by 2050 2% of global energy will be used in fertiliser production [ref 1]; this represents the single largest energy input into intensive agriculture. This is unsustainable, and if the price of oil increases, so does the price of fertilisers, and so our food. Add to this the environmental costs of these fertilisers and it is clear that we need to find another way. I believe the answer lies in plants themselves – finding a biological and sustainable means of fertilising plants.

My research looks at leguminous plants, such as peas and beans. On the roots of these plants are small growths called nodules which are factories that supply all of the nitrogen the plant needs. Within the nodules are specialised bacteria that form a mutually beneficial relationship with the plant. The bacteria take nitrogen from the air and covert it into a form that the plant can use. In exchange the bacteria are supplied with sugars produced by the plant. It’s a beautiful and elegant system, and I’m interested in understanding the fundamental science behind this association. 

This interaction involves signals between the bacteria and the plant. The signals trigger the plant to produce nodules to house the bacteria and also control the exchange of nutrients. Getting a complete understanding of the process will take a long time, but the driving force behind it is that if we can get a better understanding of the process we can look to transfer it into non-leguminous crops like wheat, rice or maize, the world’s three most cultivated crops. This would slash the amount of oil needed to grow them, and the amount of pollution caused by the fertilisers they currently need. However, transferring this process can only occur with the use of genetic modification (GM).

I see GM as a natural and biological solution to this huge problem. However, I know many people have a negative perception of GM. In this case I think the benefits are clear.

We are working very carefully and thoroughly to understand the process [ref 2,3], and then to predictably and safely transfer nitrogen fixation to crops. We know the effects of nitrogen fertiliser pollution on the environment, and we know the effect that burning huge amounts of fossil fuels has on our climate. But we do this anyway out of necessity to support current food supplies.

Balancing these very detrimental impacts against the perceived dangers of GM will, in my opinion, be the key to delivering the second, greener revolution in farming that we need to secure our food supply now and into the future.

References

1. Is it possible to increase the sustainability of arable and ruminant agriculture by reducing inputs?
2. Nodulation Signaling in Legumes Requires NSP2, a Member of the GRAS Family of Transcriptional Regulators
3. Nodulation independent of rhizobia induced by a calcium-activated kinase lacking autoinhibition

About Dr Giles Oldroyd

Dr Giles Oldroyd leads the Plant Perception and Response to the Environment Programme at the John Innes Centre. He received a David Phillips Fellowship from the BBSRC and has received a number of awards for his research, including European Molecular Biology Organisation young investigator, European Research Council young investigator, Society of Experimental Biology President’s medal and a Royal Society Wolfson Research Merit award.

Contact details

Dr Giles Oldroyd
John Innes Centre
Norwich Research Park
Colney
Norwich
NR4 7UH

Tel: 01603 450000
Email: giles.oldroyd@bbsrc.ac.uk