We are probably close to the time when the amount of food that can be grown for each person in the world will peak and then go in to decline as the population continues to grow and the problems of energy, water and land shortages get worse. In addition, global warming will cause extreme weather related crop losses from time to time.
Our modern farming system is now totally reliant on oil and gas for power, nitrogen fertilizer and pesticides and is therefore vulnerable to energy shortages caused by depletion or disruption. Phosphate, potash and other nutrients have to be mined and applied as the natural soil nutrient cycle has also been broken.
Advocates of organic farming believe that it is the only sustainable method of farming, but can it feed the world in the future?
Organic farmers do not use chemical fertilizers or pesticides. Instead they use animal manure together with crop rotation that usually includes nitrogen fixing legume crops, to build soil fertility. They claim that healthy soils produce healthy crops that are less vulnerable to disease and can thrive without chemical fungicides and insecticides. They use mechanical hoeing, hand weeding and other techniques to control weeds.
As a conventional farmer growing wheat and vegetables, I have gone along with all the latest methods to increase yields and reduce labour as they have become available, but I have the greatest admiration for those farmers who are able to work with nature and produce good food in what they say is a sustainable way. In the future we will have much to learn from these people as we build a sustainable, high yield agriculture.
But can organic farming resolve peak food and feed the world? Sadly, I think not. Unfortunately, the once and for all binge of abundant cheap fossil energy that we conventional farmers have been able to convert to huge amounts of food energy has allowed the world population to go way above what it’s carrying capacity would be without oil and gas.
In organic farming systems, yields are usually much lower and depend on high numbers of livestock to provide manure. Organic farmers usually use tractors, combines and other machinery powered by diesel and the very effective crop covers that protect crops from pests such as carrot fly, cabbage root fly etc are made from oil. Effective weed control in field scale crops is very difficult without weed killers especially in slow growing crops such as onions and carrots.
If we still had a 1930’s population of 2 billion, I think a sustainable organic system with minimal fossil inputs would work well, but to feed the 8 billion expected by 2025 would be impossible.
So, is there any way 8 to 9 billion people can be fed in 15 to 30 years time with dwindling energy, water and land resources?
I believe it is unlikely, but if there is any chance, we need to be making plans now to work out how we can collect more solar energy through plants and use it in a sustainable way.
We will need to use part of the cellulose portion of the crop for our power needs and use low till methods to leave remaining crop residues close to the surface to protect soil from erosion.
We will need to eat less meat so that arable crops can feed humans directly and restrict livestock to land unsuitable for crops. Animals can also be used to convert waste in to meat.
Research should be done to breed improved legume crops such as peas and beans that can provide vegetable protein and at the same time fix nitrogen to improve soil fertility, and we must find ways to return all nutrients to the soil, even by putting human waste through a digester to provide bio-gas and fertilizer.
There is much that can be done to devise a sustainable food system by combining the best principles of organic farming with non damaging, low energy input methods that include some help from inorganic fertilizer and low toxic pesticides. But we need to start now.
Over the past 60 years, food production has kept up with the population explosion partly due to the oil based pesticides that control diseases, insects and weeds. But now the whole world depends on the continuous development of new pesticides that are effective against pests that have become resistant to existing pesticides through selection. We kill most of the targeted pests but in time, the most resistant organisms survive the pesticide and pass on their genetic traits to their offspring.
These resistant offspring have less competition and become dominant. It’s man made survival of the fittest and can happen very quickly.
An example of the way we are losing the chemical war against pests is blight in potatoes.
In England in the late 1950’s, most potato varieties were fairly resistant to blight and were not usually sprayed with fungicide. Then farmers began to use a single application late in the growing season to keep the crop growing for a few weeks longer and thereby increase yields. We then began to apply odd sprays earlier in the season if there was a period of warm moist weather that favoured the spread of blight.
It seemed to many of us that blight was beaten, but instead we caused it to evolve quickly. The stronger strains that had survived now needed spraying every three weeks to keep the crop healthy and better fungicides needed to be constantly developed to keep on top.
We have now reached a situation that farmers of 50 years ago could not have imagined, this year we are being advised that we should start spraying as soon as the crop has emerged and then apply a spray every 7 days for the rest of the season, dropping to every 5-6 day intervals in high risk periods. This could mean up to an unbelievable 18 fungicide applications. How much worse can it get?
The new blight populations are more aggressive and more severe at lower temperatures and are more difficult to control. In just 3 years, the A2 Blue 13 strain, which is present right from the start of the season and completes it’s life cycle faster, has become the dominant strain across Britain.
Farmers are being told to use a combination of different fungicides in a robust programme to attack the blight pathogen at various points in it’s life cycle to reduce the risk of an evolving strain developing complete resistance to these fungicides.
Potato blight is just one example of the ongoing battle that pests seem to be winning. A few years ago, septoria tritici fungal populations in cereals became resistant to the highly effective strobulin fungicides. If alternative fungicides had not been available, we would have seen big reductions in yield.
The big danger is that our use of pesticides will cause the selection of a super strain of disease in a major crop such as wheat for which we do not have an effective pesticide. This could spread rapidly causing big yield losses or even crop failure and therefore food shortages.
Just another reason why our food supplies are on a knife edge and we are getting closer to Peak Food.