One of the most powerful arguments for modern agricultural chemicals is also one of the simplest.
They help produce affordable food.
It is an argument worth taking seriously. Farmers operate businesses. Fuel costs money. Machinery costs money. Labour costs money. Every extra pass across a paddock costs money. If a herbicide allows a farmer to control weeds while using less cultivation, fewer tractor passes and less diesel, there is a genuine economic benefit.
And in the case of glyphosate, there is good evidence that this happens.
In our previous article, Do Farmers Grow Food Differently When They Are Going to Eat It Themselves?, we looked at evidence suggesting that commercial economics can influence how food is grown — including how pesticides are used.
That raised another question: what are agrichemicals actually buying us?
One answer is surprisingly clear. Glyphosate can buy farmers something very tangible: lower production costs.
But there is another question hiding inside the argument.
If glyphosate makes food cheaper to produce, does that necessarily make food cheaper for us to buy?
That turns out to be considerably harder to answer.
Glyphosate Can Reduce The Cost Of Growing Food
Let’s start with something that can sometimes disappear from debates about glyphosate: it is useful.
One of its important roles in agriculture is enabling reduced-tillage and direct-drilling systems. Instead of repeatedly cultivating the soil to remove existing vegetation and prepare a seedbed, farmers can control vegetation chemically and plant with much less soil disturbance.
That can save a substantial amount of money.
New Zealand’s Foundation for Arable Research (FAR) compared cultivation systems in maize trials in Waikato, Central Hawke’s Bay and Taranaki.
Using contractor costs, FAR calculated that strip tillage was between $20 and $110 per hectare cheaper than conventional cultivation.
Direct drilling was approximately $260 to $310 per hectare cheaper.
Those are not insignificant savings.
And that wasn’t the only FAR research to find a substantial cost difference.
Another FAR long-term cultivation trial produced an even larger difference. In its Northern Crop Research Site 2015/16 Research Summary [PDF], FAR reported cultivation and planting costs from the seven-year trial of approximately:
- Full cultivation — $500/ha
- Strip till — $360/ha
- Direct drill — $150/ha
The same trial found no significant difference in maize grain yield between no-till, strip-till and full-cultivation treatments.
That does not mean direct drilling will always produce the same yield. FAR’s research also demonstrates why management matters. In its 2009 trials, for example, direct-drilled maize in Taranaki tended to yield less because of lower plant populations, with higher pest pressure from greasy cutworm appearing to be the cause. FAR identified fallow time, planter accuracy, weed control and pest control among the things farmers need to get right.
But the economic attraction is easy to understand.
If you can establish a crop successfully without repeatedly cultivating the paddock, you potentially save machinery, labour, diesel and time.
Glyphosate can help make that possible.
But Glyphosate Isn’t Saving $300 A Hectare By Itself
There is an important distinction here.
It would be misleading to look at a $300-per-hectare difference between direct drilling and conventional cultivation and say:
Glyphosate saved the farmer $300.
It didn’t.
The saving comes from changing the farming system.
Glyphosate is one of the tools that can make that system possible because vegetation that might otherwise have been controlled mechanically can instead be controlled chemically.
FAR has previously described just how important that relationship had become in New Zealand. It reported that more than 500,000 hectares were under reduced cultivation and direct drilling and said those practices were heavily dependent on the repeated use of glyphosate.
The same principle appears in pastoral farming.
DairyNZ’s guidance on pasture renewal describes “spray and drill” as sowing directly into an uncultivated paddock after the existing pasture has been killed with herbicide. Among its advantages, DairyNZ lists being less expensive and less time-consuming than cultivation.
So there is a perfectly reasonable economic case here.
Glyphosate can enable farmers to produce crops or renew pasture using fewer cultivation operations.
That can make agricultural production cheaper.
But notice what we have established.
Cheaper to produce.
We haven’t yet established cheaper to buy.
What Happens To The Saving After The Farm Gate?
Imagine that a farming system reduces the cost of producing a crop by $200 a hectare.
Where does that $200 go?
Perhaps the farmer keeps some of it as improved profitability.
Perhaps competitive pressure means some is reflected in the price paid by a processor.
Perhaps a processor captures some of it.
Perhaps a wholesaler does.
Perhaps a retailer does.
Perhaps consumers ultimately receive much of the benefit through lower prices.
Most likely, depending on the product and market, the answer is some combination of these.
The important point is that a reduction in the cost of production does not automatically tell us what happens to the retail price.
There are a lot of steps between a paddock and a supermarket checkout.
And New Zealand’s grocery market gives us particularly good reason not to assume that savings made somewhere in the supply chain simply flow through to consumers.
New Zealand’s Grocery Market Complicates The Cheap-Food Argument
In 2022, the Commerce Commission’s market study into New Zealand’s grocery sector concluded that competition was not working well for consumers.
It found that the major grocery retailers dominated the market, competition between them was muted, retail grocery prices appeared comparatively high internationally, and many suppliers faced an imbalance in bargaining power when dealing with the major retailers.
Four years later, the fundamental structure had not changed very much.
In its June 2026 update, the Commerce Commission reported that the major supermarket groups still held more than 80% of the national retail grocery market, while retail prices had increased.
The Commission has also been investigating the extraordinary complexity of payments between suppliers and supermarkets.
In July 2026 it reported identifying more than 50 different types of supplier payments, collectively accounting for around $6 billion paid by suppliers to the major supermarkets annually. These can include rebates, discounts and payments for services such as promotional support, shelf restocking and other retail activities.
None of that proves that supermarkets capture savings created by glyphosate.
But it does demonstrate why the journey from farm production cost to checkout price is far more complicated than it might first appear.
Indeed, the Commerce Commission reported in 2024 that its analysis showed retail prices for major grocery brands had been increasing faster than the prices supermarkets were paying suppliers. It described unconstrained retail margin growth as a warning sign for competition.
The picture can also change from year to year. In 2024, the Commission subsequently found that supermarket input costs increased faster than retail prices and gross product margins contracted slightly.
Which illustrates the point rather neatly.
There is no simple conveyor belt carrying a saving made on the farm directly to the person standing at the checkout.
So Who Benefits From Cheaper Production?
Perhaps this is the question we should have been asking all along.
If glyphosate helps a farmer reduce establishment costs by $200 or $300 per hectare, who gets the benefit?
There is no reason to assume there is only one beneficiary.
The farmer may benefit through lower costs, particularly if the price received for the crop remains unchanged.
Processors and other buyers may benefit if lower production costs eventually influence the prices at which agricultural commodities can profitably be supplied.
Retailers may benefit.
Consumers may benefit if lower costs contribute to lower retail prices or restrain price increases.
And there may be another benefit that is easily overlooked: maintaining the economic viability of farming itself.
A farmer who can reduce the cost of establishing a crop without reducing its yield has gained something very real, even if the supermarket price of the finished product does not move by a cent.
That matters.
But it is different from saying glyphosate makes food cheaper for consumers.
We have evidence for the first proposition.
Demonstrating the second requires following the money much further down the supply chain.
Then There Are The Costs We Don’t See At The Checkout
There is another complication.
Economists have a word for costs created by an activity but borne by somebody outside the transaction: externalities.
The idea sounds more complicated than it is.
Suppose producing something costs $10, but its production also causes $2 worth of damage that somebody else eventually has to deal with.
The producer’s accounts may still show a cost of $10.
The true cost to society may be $12.
Pesticides provide plenty of potential examples.
Research into pesticide economics has long recognised that farm-level calculations usually include obvious costs such as purchasing and applying a pesticide, while other possible costs — environmental effects, human-health impacts, resistance and government expenditure on monitoring or remediation — can occur outside the farm accounts.
A recent meta-analysis of the economic literature makes another important point: there is no single reliable global figure for the external cost of pesticide use. Estimates vary enormously according to the pesticide, risk, location, exposure and method used to value the damage.
That matters enormously for this discussion.
We cannot take an estimate of the external costs of pesticides generally and simply assign it to glyphosate.
Different chemicals behave differently. Different farming systems use them differently. Exposure differs. Environmental effects differ.
So it would be equally misleading to claim that glyphosate only appears cheap because society is secretly paying some enormous hidden bill.
We don’t have evidence that allows us to make that calculation.
What we can say is that the price of an agricultural input does not necessarily capture every cost associated with using it.
But What Happens If We Take Glyphosate Away?
Here the story becomes more interesting again.
If glyphosate helps make reduced-tillage farming possible, replacing it may create costs of its own.
A return to mechanical weed control can mean more tractor passes, more fuel, more labour and more disturbance of the soil.
It can also mean more erosion.
This isn’t merely theoretical.
Researchers studying thousands of US soybean fields examined what happened as weeds developed resistance to glyphosate.
Their study, published in the American Journal of Agricultural Economics, found that as the number of glyphosate-resistant weed species increased, farmers increasingly responded by using more intensive tillage as well as more non-glyphosate herbicides.
By the time eight glyphosate-resistant weed species were identified at state level, the researchers estimated that conservation tillage had fallen by 3.9 percentage points and no-till by 7.6 percentage points.
Then they tried to put a price on some of the consequences.
For US soybean production between 2008 and 2016, they conservatively estimated approximately US$245 million in cumulative water-quality and climate damages associated with the additional soil erosion and fuel emissions resulting from farmers’ tillage response to glyphosate-resistant weeds.
Even that estimate did not include carbon released through additional soil disturbance or changes in the environmental and health costs associated with using other herbicides.
There is a curious lesson in that.
Glyphosate use can potentially create external costs.
But losing the effectiveness of glyphosate can create external costs too.
Cheap Compared With What?
That may be the most useful question in this entire discussion.
Agriculture rarely offers a choice between something that has costs and something that doesn’t.
The choice is usually between different systems with different costs.
Chemical weed control has costs.
Mechanical weed control has costs.
Cultivation uses machinery and fuel and disturbs soil.
Herbicides require manufacture, transport and application and can move beyond their intended target.
Reduced tillage may protect soil structure and reduce fuel use, but it can increase reliance on herbicides.
And over-reliance on a herbicide can eventually encourage resistance, potentially pushing farmers back towards more cultivation or towards additional herbicides.
It is less a choice between “cheap” and “expensive” than a question of which costs we choose, who pays them, and when.
Maybe We Need To Rethink What We Mean By Cheap Food
The argument that glyphosate helps keep food affordable contains an important truth.
Glyphosate can make some farming systems less expensive.
New Zealand research provides quite striking evidence of that. Direct drilling can substantially reduce establishment costs, and glyphosate has been an important enabling tool in reduced-cultivation systems.
Those benefits shouldn’t be waved away simply because they complicate the debate about glyphosate.
But neither should we quietly turn lower production costs into lower supermarket prices without evidence showing how one becomes the other.
Between the farmer and the checkout sit processors, manufacturers, transporters, wholesalers, retailers, contracts, margins, bargaining power and competition.
And beyond the checkout sit costs that markets do not always price neatly — environmental effects, resistance, regulation and monitoring — alongside the environmental costs that might arise from whatever system replaces the one we currently use.
So perhaps “Does glyphosate make food cheaper?” is the wrong question.
Perhaps the better questions are:
What does glyphosate make cheaper?
Who receives that saving?
Which costs have genuinely disappeared — and which have simply moved somewhere else?
Because a technology can make food cheaper to produce without necessarily making our supermarket bill cheaper by the same amount.
And until we know where the savings actually go, those are two very different claims.
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