– Opinion piece
With Rob Eccles, Catchment Solutions Agricultural Innovation
M: 0439 308 179 | E: firstname.lastname@example.org
People pitch when asked this question from many agendas. Some say all synthetic chemicals are evil and we should renounce them all as they are only serving the purposes of large politically manipulating multinationals. Others say they are essential products to modern agriculture under continual improvement and are tools that enable us to feed the world population.
As an agronomist now with some age I’ve learnt that there is more than one right answer. Certainly this is the case here. I’m sympathetic to most of the views here. Some are emotive and philosophical. I’ll just add a few experiences to the discussion.
Once people get past food production for themselves we can call them a farmer. Before then they can use whatever system they like to grow food for themselves. Cost efficiency is not a large consideration. They can renounce conventional synthetic fertiliser and chemicals if they feel they need to, don’t know how to or can’t afford them.
Farmers being subjected to market forces however will use whatever technology and system to grow food available to them. They are competing against every other farmer on the planet usually on price and quite often on hygiene and appearance.
As featured on the SGU Podcast a few weeks ago some places on the planet are more greenhouse efficient to grow a particular food than others. Large farms in the right place with economies of scale can grow food doing less total harm to the planet than others a continent away with low yields. Twelve tonnes of grain per hectare grown in the right place is better than 3 tonnes grown in the wrong environment. Pumpkins grown in Queensland Australia is more efficient to sell in Japan than selling locally grown ones produced in Japan. Corn flour from the USA is more efficient than cornflour grown and processed locally in Hungry. I hope these examples help.
I give advice to clients on many sides of the fence. Advice to small farms to large corporate farms. Those who are organic and those who are conventional. I have many clients who integrate components of all systems. For example some use recycled organics and top up with synthetic fertiliser.
My main point in this post is that a lot of emotive energy is used to throw stones at the tools used by farmers to grow food. Faced with at least 100 years of the unrelenting cost-price squeeze farmers have to continually grow more or become non-viable. To stand still in farming is to go backwards. I am sure from working with and thinking with hundreds and thousands of farmers many of them would be delighted to relax a bit from their industrialised farming system. Unfortunately this will not happen with the people of the world wanting to pay less and less for food. As mentioned above there are also added costs of to farmers of traceability and visual point of sale food like fruit and vegetables farmers often tell me they cannot sell about 25-35% of their produce because of rejection due to the wrong size, shape or visual blemishes. These were not costs and issues 10 or so years ago. I’m not sure of the exact percentage points but I believe households of the developed world spend less than 10% of their incomes on food. In the 1950’s that was around 40%. If people are willing to pay four times more for their food then we can do away with corporate farms, many synthetic chemical and fertilisers.
Now back to the original discussion question. I find it difficult to see direct soil destruction from herbicides. A one off application of glyphosate is a minimal amount of chemical in a hectare of soil 25cm deep. There are many agents in the soil that denature glyphosate very quickly such as clays and microorganisms. One kilogram of glyphosate from a typical application to 2.5 million kilograms of soil per hectare in the 25cm root zone is not an overwhelming challenge for these agents. I have read the recent publications on glyphosate in regard to mammal health and it is early days yet to jump to any panic linking it to human well-being. Glyphosate has been continually picked on for 30 years. Mud has not stuck very well as yet. So let’s watch this space. We are not drinking glyphosate so presently I view this is as similar paranoia to human vaccinations. Celebrities scare people talking about their “mummy sense”. How many children have died from this vaccination debate? How many people will die of starvation if we suddenly renounce herbicides?
A farm system reliant on herbicide use does damage soils by causing very efficient weed free fallows. Many symbiotic beneficiary soil organisms cannot survive for very long in viable populations without living plant roots feeding them exudates. VAM also called AM Fungi are an example group of organisms. Long fallow disease is the term used to describe crops in soils that have lost or depleted populations of these essential organisms.
Some herbicides can deplete soil microorganisms directly such as triazines but if these are used in rotation with other chemicals and if a farm system has enough rainfall or irrigation to avoid long fallows then these will recover. There are also commercially available soil microbe inoculums available to restore these populations. This is an unregulated part of the market so caution and scepticism is advised. As much as some readers have their concerns for AgChems and synthetic fertilisers, remember these are regulated.
Herbicide resistance has been mentioned in the posts. In Australia we had 37 populations of weed resistance in 2011. We would have more now. This is an extension issue. As with animal health drenches for parasites, antibiotics with humans a simple herbicide rotation ideally with a crop rotation strategy solves this problem.
As for the original question on soil health and herbicides a country like Australia with an unpredictable climate, a hot climate that naturally has soils low in organic carbon and with mostly shallow ancient soils we will not have not been able to continue growing crops without herbicides. Early in my career I experienced the introduction of minimum tillage that quickly evolved into zero-tillage. This has saved our soils from destruction. By the early 1980’s farm land in Australia had washed out gullies, scalped topsoil, silted waterways and particulate soil matter plumes fanning out into our oceans and the Great Barrier Reef. Many of our crop soils had lost their top 10 cm.
Monsanto’s glyphosate (Round-up) and ICI’s diquat and paraquat (Spray Seed) were developed and used as the tools to stop the destructive cultivation on our fragile soils. We had no option for sustainability to continually use cultivation. If we were in a cooler country with deep glacial soils it may have been a different story. Both these companies made a huge investment in developing the system. Some may think large corporates are evil; my experiences are that they merely respond to market forces and have done a lot of good in this case. Any chemical used off label or abused can do harm. So can a gun.
Using minimum tillage and zero-tillage practices involve using a range of chemicals. Typically the same farms use synthetic fertilisers. Their use are the most cost efficient way of getting absent and consumed nutrients onto a farm. In Australia we have enough recycled organics to satisfy 3% of our fertiliser needs. They can be stretched to 8% of our farm land if we use lowers application rates per hectare with microbial inoculums and a top-up of synthetic fertiliser. The rest of our farms need synthetic fertiliser to stay viable. As I said above if the world populations want to pay Australian farmers 4 times more for their food then alternate proven methods can be used. I would suspect this is largely a similar case in other countries.
For the original question a final thing I want to share is the effect of a properly implemented farm system with herbicides and synthetic fertilisers. Those same grain farmers I consulted in 1990 who had soil organic carbon levels mostly between 0.6% and 1% had in 2010 their organic matter in the 3% and 5% range after using zero-tillage for 15-20 years. These were measured by research scientists in our Department of Agriculture.
My answer to the original question. If following the recommended farming system continually being developed that combines the use herbicides soil health is not destroyed.