How Demand and Supply Determine Agricultural Prices

In early 2026, onion farmers in Maharashtra watched their crop become almost worthless. A bumper harvest met a sudden fall in export demand, and mandi prices collapsed to as low as Rs 300 to Rs 800 per quintal, well below what it cost farmers to grow and transport the crop. A few months later, the same crop can just as easily double in price after one bad monsoon. This is not random chaos. It is demand and supply doing exactly what economic theory predicts, just with far more drama than you would see in the market for, say, toothpaste. Understanding why agricultural prices behave this way, and why the government keeps stepping in, is one of the more practical lessons microeconomics has to offer.

A market that behaves like the textbook model 🔗

Most industries in the real world are messy versions of perfect competition. Farm produce markets, especially for staples like wheat, rice, and pulses, come remarkably close to the textbook ideal. There are millions of farmers growing more or less the same crop, thousands of buyers, and no single participant large enough to move the price on their own. Produce from different farms is largely interchangeable once it is graded, information about prevailing prices is publicly available at the mandi, and anyone can, in principle, start farming or stop farming without legal barriers.

Why no single farmer can set the price 🔗

This is the defining feature of such a market: every farmer is a price taker, not a price maker. A wheat grower in Punjab cannot decide to charge more than the going mandi rate, because buyers will simply purchase from another farmer offering an identical sack of grain. The price is decided collectively, by the intersection of the market demand curve and the market supply curve, and each individual farmer simply accepts whatever that price turns out to be on a given day.

What shapes demand for agricultural commodities 🔗

Demand for food staples is driven by population, income levels, and consumption habits, but it moves slowly and predictably compared to supply. Rice and wheat are necessities, so people keep buying roughly the same quantity even when prices rise or fall somewhat. Economists describe this as inelastic demand, meaning the percentage change in quantity demanded is smaller than the percentage change in price.

That said, demand is not perfectly fixed. It shifts with a few identifiable factors:

• Population and urbanisation: more mouths to feed means the demand curve gradually shifts rightward every year.
• Income growth: as household incomes rise, demand for pulses, edible oils, fruits, and vegetables tends to grow faster than demand for basic cereals, a pattern economists call rising income elasticity for high-value foods.
• Seasonal and festive spikes: demand for specific commodities, such as onions or ghee, jumps sharply around festivals and weddings, pushing prices up temporarily even without any change in supply.
• Export demand: when global buyers enter or exit the market, as seen with onion exports being disrupted by conflict in West Asia, the effective demand facing Indian farmers shifts even though domestic consumption habits haven’t changed at all.

Why supply behaves so unpredictably 🔗

If demand for food is fairly stable, most of the price volatility in agricultural markets comes from the supply side. Farm output depends on factors no farmer fully controls.

Rainfall timing and quantity, temperature, pest attacks, and soil conditions all directly affect yield. A delayed monsoon or an unseasonal hailstorm can wipe out a large share of a season’s crop with almost no warning. Because crops take months to grow, farmers cannot simply “produce more” the week prices rise, the way a factory might add a shift. And for perishable produce like onions, tomatoes, and most vegetables, there is little cold storage capacity to hold back supply when the market is oversupplied, so everything that is harvested has to be sold quickly, crashing prices further.

The cobweb pattern: farmers react to last year’s price 🔗

There’s a well-documented pattern behind India’s frequent onion and potato price crashes. When prices are unusually high one season, many farmers rush to plant that crop the following season, expecting the good returns to continue. Everyone acting on the same signal at the same time produces a glut, and prices collapse when the new harvest arrives. Discouraged, farmers then cut back the following season, supply shrinks, and prices spike again. Agricultural economists call this cyclical overshooting the cobweb effect, and it is a big reason why onion and potato prices in Indian mandis swing so violently from one year to the next.

How shifts in demand and supply move the equilibrium 🔗

The underlying logic is standard demand-supply analysis. Whenever one curve shifts while the other stays fixed, both the equilibrium price and the equilibrium quantity change in predictable directions.

In practice, both curves often move at once. A poor monsoon can shrink supply while simultaneously pushing up rural incomes from other sources, nudging demand slightly higher too, which makes the resulting price movement even sharper than either shift would cause on its own.

Why farm prices swing more than factory-made goods 🔗

This is really the heart of the pricing problem in agriculture. A UK Parliament committee report on food price volatility, drawing on research from the Food and Agriculture Organization and the OECD, identifies three structural reasons agricultural prices are inherently more volatile than prices in most other sectors. First, output is vulnerable to weather shocks and pests that no one can fully predict. Second, because both demand and supply for food are inelastic in the short run, even a small shortfall in production requires a disproportionately large price increase to ration the available supply among buyers, and a small surplus requires an equally large price fall to clear the market. Third, because farming takes a full season to respond to price signals, supply cannot adjust quickly, so temporary shocks tend to work themselves out through price rather than through quantity.

Put simply: when a factory faces a demand shift, it can usually adjust production within weeks. When a crop faces a supply shift, the market has almost no cushion until the next harvest, so the price has to do all the adjusting.

Minimum support price: the government’s floor 🔗

Because unmanaged price swings can push mandi rates below the cost of cultivation, especially in a bumper year, the government sets a Minimum Support Price for major crops each season. The Commission for Agricultural Costs and Prices, an office under the Ministry of Agriculture and Farmers Welfare, recommends MSPs for 23 commodities across cereals, pulses, oilseeds, and commercial crops, with the explicit aim of encouraging farmers to keep investing in better technology and stable output even though farm markets are inherently unstable. The Cabinet Committee on Economic Affairs takes the final call on the announced price, and procurement agencies such as the Food Corporation of India step in to buy at MSP whenever market prices threaten to fall below it.

MSP does not replace demand and supply. It simply sets a floor beneath the equilibrium price so that a genuinely bumper harvest, which is good news for the country’s food security, doesn’t turn into a financial disaster for the farmers who produced it.

PM-AASHA: the safety net beyond MSP 🔗

MSP only helps if the government can actually procure the crop, which is logistically difficult for perishable items or crops grown outside the main procurement network. To close this gap, the government runs the Pradhan Mantri Annadata Aay Sanrakshan Abhiyan, or PM-AASHA, an umbrella scheme with several components. The Price Support Scheme allows physical procurement of pulses, oilseeds, and copra at MSP whenever market prices dip below it during peak harvest. The Price Deficiency Payment Scheme takes a different route: instead of buying the crop, the government directly transfers the gap between the MSP and the actual selling price into the farmer’s bank account, which avoids the cost of storing and transporting large volumes of grain. A separate Market Intervention Scheme covers perishable horticultural produce, like onions or tomatoes, that don’t have a notified MSP at all but can still suffer sharp price crashes in a glut.

e-NAM and the push for better price discovery 🔗

A separate problem in agricultural markets is information. A farmer selling in one mandi often has no easy way of knowing whether a neighbouring mandi, or a buyer in another state, is offering a better price. This lack of information keeps some farmers dependent on local traders and middlemen. The government’s response was the National Agriculture Market, or e-NAM, a pan-India electronic trading platform launched in 2016 that digitally links existing APMC mandis so that produce can be traded, priced, and paid for online across state lines. By connecting markets that used to operate in isolation, e-NAM aims to make price discovery more transparent and give farmers access to a much wider pool of buyers than their nearest mandi alone.

None of these interventions, MSP, PM-AASHA, or e-NAM, override the basic forces of demand and supply. They work alongside the market, cushioning its extremes without replacing the price mechanism that ultimately decides what gets grown, how much, and at what price it reaches your kitchen.

What do you think? If MSP guarantees a floor price for over twenty crops, why do onion and tomato farmers still face such extreme price crashes almost every year? And as India expands digital platforms like e-NAM, do you think better information alone can fix the volatility that comes from weather-dependent supply, or will price swings always be part of farming?

References

1. https://www.downtoearth.org.in/agriculture/war-in-west-asia-and-protectionist-steps-by-bangladesh-disrupt-onion-exports-lead-to-price-crash
2. https://www.fao.org/fileadmin/templates/est/meetings/price_volatility/Price_volatility_TechPaper_V3_clean.pdf
3. https://cacp.dacnet.nic.in/content.aspx?pid=32
4. https://www.pib.gov.in/PressReleasePage.aspx?PRID=2113721
5. https://www.pib.gov.in/PressReleasePage.aspx?PRID=2251543&reg=3&lang=1