Unquestion #12: When the PPF Shows the Floor and Science’s Potential

The record has always been in plain sight.

Farmers decide at the start of production based on the income they expect ahead at harvest. For each farmer, this is a decision on the Production Possibilities Frontier, the PPF: yield to seek, labor and input to use, information to apply, and exchange to expect. This is the production decision we see.

Across farms and production cycles, those PPF decisions add up. Whether farmers keep producing at the same, lower, or higher yield level tells us whether the income expected ahead is being realized when they sell what they produce. This is what we see.

Where income expected ahead is little, movement on the PPF is little too, and yield stays at the low level that income sets. Partway up, yield reaches only partway and stays there where income remains unchanged, or rises only at the pace income grows. When public support provides the income expected ahead, yield rises to where that support takes it. When income is realized from cycle to cycle, production continues from PPF to PPF. Where income expected ahead holds and remains high, farmers move toward science’s potential. Along the way, yield can slow or pause at the level the income ahead makes worthwhile. This is the record we see.

India’s Green Revolution shows the great lift from the floor, and the great slowing afterward.

India’s Green Revolution begins in the 1960s as a necessary intervention for a subcontinent facing food scarcity. New varieties, irrigation, fertilizer, and price support, largely provided through public support, lower production costs enough for income to be seen ahead, or at least for the farmer to break even at harvest, moving rice and wheat sharply upward in yield and area. Food sufficiency for the population and national food security follow. Farmers move on the PPF, lifting yields greatly from the floor, even while yields remain well below science’s potential. This is the record we see.

Yields, still growing at more than 3 percent a year by the 1980s, slow sharply in the following decades to a little over 1 percent by the 2000s, while public support continues in full and vast areas under still-low yields keep total production rising. Grain stocks reach abundance with public granaries overflowing. But the great lift in yield falters while the public support continues even today. This too is the record we see.

Maize in Kenya shows the floor.

When income expected ahead is little, yield settles near the floor, far below science’s potential. Maize yield has stagnated around 2 tons per hectare or below for decades across Africa, and not far above that in many economies elsewhere. In Kenya, the highest average yield recorded for maize since 1960 is 2.1 tons per hectare in 1982, more than four decades ago. Decades of elaborate projects bringing fertilizer, credit, teaching, market, and other support to smallholders have left them in much the same low-productivity maize near the yield floor as under the Green Revolution. This is long-standing stagnation near the floor of science’s potential. This is the record we see.

Cocoa shows the smallholder floor while demand and land area rocket.

The movement on the PPF does not depend on whether the crop is a staple or non-staple, major or minor. Cocoa is grown in narrow-based economies by about 5 million smallholders, and the area under cocoa is only a small fraction of the area under maize or other cereals. Cocoa average yield has stayed near the floor as far back as the record reaches, around 0.5 tons per hectare or less, barely one-eighth of even a low-end yield potential, depending on cocoa type and production system. Even that 0.5 tons per hectare overstates the smallholder yield, because niche plantations connected to export value chains that harvest closer to science’s potential are also part of that average.

From the mid-1990s, cocoa demand rockets, and that demand is met solely by area expansion. Land carries what yield does not, while forests fall in the tropical zones where cocoa expands. The high value of cocoa stays beyond the smallholder farm gate, and little income at the farm gate leaves the smallholder’s yield at the floor. This is the record we see.

Coffee shows the smallholder floor under high export demand.

Twelve million hectares under coffee is tiny beside the roughly 0.7 billion hectares under cereals in narrow-based economies. About 60 percent of global coffee supply comes from about 12.5 million smallholders farming 80 percent of coffee farms. Over the past six decades, average coffee yield rises from under 0.5 tons per hectare in the 1960s to still below 1 ton per hectare today, far below science’s potential, which is fourfold or more above the average depending on coffee type and production system. The smallholder yield is below even that 1 ton, because niche plantations connected to export value chains that harvest several-fold higher are also part of the average. This is the record we see.

Maize in Malawi shows the subsidy lift.

Farmers move on the PPF even when public support changes the income they expect ahead. Malawi’s maize yield rises from stagnation below 2 tons per hectare before 2005 to 2.7 tons per hectare in 2007 through seed and fertilizer subsidies. The initial lift then tails off, and yield returns to stagnation at 2 tons per hectare and below even as subsidies continue in varying form. The subsidy lifts yield only as far as the income ahead allows. For the production decision, that public transfer is still income expected ahead. This is the record we see.

India's White Revolution shows continuation from PPF to PPF.

Farmers continue from PPF to PPF when income expected ahead is held by repeated exchange. India has one dairy animal per 12 people, mostly raised for sustenance at very low milk yield. A consumer-facing quasi-government cooperative enterprise uses the hydrometer for rapid assessment of milk purity at the farm gate. It bulks, processes, and sells milk and milk products to consumers. The hydrometer makes purity self-enforceable by farmers before milk enters the value chain. This is the mechanism we see.

Once purity is self-enforced by farmers at the farm gate, the enterprise keeps buying, processing, and selling milk and milk products. And the farmer keeps producing milk for the reliable income it brings. Consumer-facing private dairies later copy the same hydrometer mechanism. If it were not for the hydrometer, the repeated exchange would not hold.

India’s cow milk supply increases about fifteen-fold from 1970 to 2023. Average milk yield per cow rises by about 425 percent over the same period.

But the movement on the PPF remains partial to where the hydrometer, the buyer, and the farmer meet at the farm gate. Only a small share of Indian dairy farmers are reached by the cooperative network and the private dairies. Milk production in India still stays far below science’s potential. Yet even this partial lift across farmers and places in India is still a revolution. It is the White Revolution. This is the record we see.

Kerala shows that high human development does not replace income on the PPF.

Kerala has long had much of the human capability Development seeks to build. Education, literacy, health, science, and knowledge are widely present, and income per person is above India’s average, though still far below the World Bank high-income threshold.

Rice, a staple in Kerala, shows what farmers do with all of that already there. Area falls from about 0.9 million hectares in the mid-1970s to about 0.2 million hectares four decades later. Average yield rises only modestly and remains around 3 tons per hectare, far below science’s potential. Kerala farmers have knowledge, education, labor, land, and access to science. But inexpensive rice also arrives through India’s heavily supported production elsewhere, while the same land, labor, and other factors have other uses. Farmers do not pursue rice yield toward science’s potential simply because they can. On the PPF, those factors go where greater income is visible. This is the record we see.

Maize in Bangladesh shows the move toward the ceiling that science sets.

Farmers move toward science’s potential where the crop fits the place and income expected ahead holds across farmers. For decades, Bangladesh maize yield stays at the floor at about 1 ton per hectare or below, while rice and wheat yields move on the PPF, clearing the floor but only in tandem with GDP per capita growth.

Then a rare extended scarcity in feed maize makes income expected ahead hold for maize. Maize yield rises from the floor starting in 2000 and reaches science’s potential near 10 tons per hectare over the next two decades. Maize area expands from about 3,000 hectares in 1999 to about 0.7 million hectares in 2024. Because the scarcity-driven income run begins from very little maize area, maize expands where the crop fit is strongest. Where income expected ahead holds strongly enough, farmers move toward the ceiling science sets. This is the record we see.

A national smallholder agricultural economy shows farmers moving on their PPFs with income.

Around the turn of the century, smallholders made up nearly all farmers and farmed about 80 percent of farmland in China. From that smallholder starting point and a narrow-economy base, GNI per capita rises sharply over the next two decades, from about US$1,000 to about US$14,000 in 2025, reaching 99 percent of the high-income threshold. Farmers’ positions on their PPFs change alongside, with farmer income, measured as agricultural GDP per capita, rising from about US$1,500 to about US$8,600 as the wider economy changes.

Crop yields, already rising before the turn of the century, continue upward with different distances left to move. Rice yield, already near two-thirds of science’s potential, continues upward more slowly to about 7 tons per hectare and then pauses there in later years, as income continues rising across the wider economy. Maize yield, starting from about one-third of science’s potential, rises toward two-thirds, reaching about 6.7 tons per hectare. In areas of best crop fit, rice yield exceeds 9 tons per hectare and maize yield exceeds 10 tons per hectare, near the potential science sets there. Average cereal yield is at 6.6 tons per hectare in 2025. This too is the record we see.

A large-farm agricultural economy shows the same PPF response.

Uruguay begins from a very large-farm agricultural economy. Its GNI per capita is about US$3,000 in 1980, rises to about US$7,000 by 2000, crosses the high-income threshold in 2012, and is near US$24,000 today. Rice is grown largely for export in areas of strong crop fit. In the early 2000s, average yield is above 6 tons per hectare, already far above the floor. Area stops expanding while yield rises to 8 tons per hectare, then pauses there for roughly a decade.

Yield later moves again to above 9 tons per hectare while rice area declines, resulting in roughly the same production from less land. Recent national average yield is around 9.3 tons per hectare, at Uruguay’s highest recorded level and still below science’s potential. As national income continues rising, farmers keep adjusting land and other production factors on the PPF under the costs and requirements they face, toward the income they can realize rather than toward yield as an objective in itself. This is the record we see.

Across crops, places, and economies, the PPF response is consistent.

India’s Green Revolution quickly lifts rice and wheat yields from the floor with public support, but yield growth significantly slows later even with continued support. Subsidy also lifts Malawi maize yield for a short period but only to fall back to where it was before.

Maize yield stagnates near the floor for long across many economies. In cocoa, rocketing global demand is met solely by more land put to cultivation while yield stays at the floor. In coffee, even with high-value export demand, the yield stays far below science’s potential while most coffee is grown by smallholders. In Kerala, rice yield stays well below potential and rice area greatly drops despite high human development and widely present knowledge there. The vastness of land under cereals, the high value of export crops grown on a small share of land, and high human development and knowledge do not change the smallholder response on the PPF; only the income expected ahead from farming does.

In India dairy, the hydrometer makes pure milk self-enforceable at the farm gate, and farmers continue producing from PPF to PPF where pure milk can be collected, processed, and sold to consumers. In Bangladesh maize, income expected ahead holds strongly enough to carry the farmer, supplier, buyer, processor, feed mill, and consumer through the chain, and farmers move on the PPF toward the ceiling science sets where maize fits.

China and Uruguay then show the same PPF responses across whole agricultural economies, one dominated by small farms and the other by large farms. In China, farmers move on their PPFs as farmer income, national income, and crop yields rise from a smallholder agricultural starting point. In Uruguay, large rice farms show the same response as national income rises, with yield moving, pausing, and moving again while land is reallocated. Farm size does not change the response on the PPF.

Across them, the farmer response is consistent. The record shows movement on the PPF staying low, lifting, slowing, falling back, continuing, pausing, and reaching toward the ceiling science sets where crop fit allows, according to the income expected ahead and how far it carries that movement.

The farmer moves on the PPF first.

When income gives the farmer reason to move on the PPF, those selling to and buying from farmers also move on their PPFs for the same reason. This is ordinary in broad-based economies where the potential to earn is visible to the many. In narrow-based economies, the potential to earn is visible only to the few.

As yield rises on the farmer’s PPF from cycle to cycle, more and more science enters the PPF. Farmers seek and use knowledge and information. Public goods and services come into use. Farmer demand for inputs is met by suppliers. Credit has a repayment path. More income becomes available to allocate as it is realized, while income expected ahead gives the farmer reason to keep moving on the PPF. Average yield speaks for the changing income condition of the place, and that itself is scale at the level of the place. Addressable markets grow with income and entrepreneurship flourishes.

What gets read as behavioral departures for the many in poverty is their response under the income and risk visible on their PPFs. Decades of teaching, groups, credit, inputs, information, and now AI for Development do not move farmers on their PPFs where income expected ahead is not seen. When the farmer has reason to move on the PPF, science of production scales even in the poorest places, as televisions, mobile phones, and mobile payments spread when they have reason to spread. The production decision on yield comes first. The things we keep offering enter after that movement has reason to begin. This is what we see.

Farmers move toward science’s potential in narrow and broad alike.

Farmers move toward science’s potential where the crop fits best and income expected ahead holds. Maize farmers in high-potential areas of Iowa and Nouvelle-Aquitaine move on their PPFs toward the ceiling science sets in those places in broad-based economies. Farmers growing maize in high-potential areas in Bangladesh move on their PPFs toward the ceiling science sets there in a narrow-based economy. In niche cocoa and coffee plantations connected to export value chains, farmers move on their PPFs toward the ceiling science sets. In China, where national income has risen sharply from a smallholder agricultural starting point, the same response is visible in high-potential places. Maize farmers in high-potential areas of Xinjiang move toward the ceiling science sets for maize there. Rice farmers in high-potential areas of Jiangsu move toward the ceiling science sets for rice there. Large rice farmers in Uruguay, growing rice largely for export in areas of strong crop fit, show the same movement in a very different agricultural economy as national income rises. Whether in a narrow- or broad-based economy, whether farms are small or large, the same movement appears where crops fit the place. This is the record we see.

The crisis of the Questions.

Evidence of scale has always been in plain sight through the PPF, yet the role of income expected ahead in farmers’ movement on the PPF remains the least seen and the most consequential for Development. This is the crisis of the Questions: yield settles at different points on the PPF according to how far income expected ahead carries movement, while average yield sums that movement across the economy.

Average yield has been speaking for the income condition of the whole economy all along. It is the accumulated expression of PPF decisions across the economy. When it settles well below science’s potential across farmers and cycles, it is evidence that income expected ahead, whether made in the market or paid by someone else, is not present strongly enough to carry yield farther.

The same low average yield is repeatedly seen as evidence that science, inputs, credit, information, public goods and services, investment, entrepreneurship, and enterprises are missing or must be provided. Yet it is already evidence that income expected ahead is not sufficient for those things to enter use and continue across the PPFs of the many.

When the budget line holds at very little income, there is little left after current consumption to put to use on the PPF. With no income seen ahead either, what the many do on their PPFs is to stay at low yields, and smallholders default to farming for sustenance. Yet those responses across the many smallholders are seen as behavioral departures while the few who respond differently are seen as evidence of positive deviance. The context shown by average yield, and the scale already present at its settled levels, remain buried by the Questions. This we Question.

Income is what scales in the record.

India’s Green Revolution scales rice and wheat sharply up when public support makes income expected ahead visible across farmers, before yield growth slows greatly while that support continues. Malawi shows maize yield rising at scale initially when subsidy lowers production costs, but yield stays low or falls thereafter even with subsidy.

Kenya maize and global cocoa and coffee show scale holding near the yield floor. In cocoa, rising export demand keeps only cocoa area rising at scale, not yield; in coffee, average yield remains far below science’s potential at scale. Dairy in India shows production continuing to rise at scale only where repeated exchange holds at the farm gate.

Kerala shows that high human development does not alter the PPF response: rice yield stays low while rice land is put to other uses where greater income is expected ahead. Bangladesh maize shows yield scaling from the floor toward science’s ceiling once income expected ahead holds across cycles. Both China and Uruguay show national income and farm yields rising together as farmers move on their PPFs, from a national smallholder agricultural starting point in the former and a national large-farm agricultural starting point in the latter.

Poverty is income scaling at poverty-level income. Every settled position across farmers’ PPFs is already scale under the income expected ahead that is visible there. Yield can stay low, lift partway, slow, fall back, pause, spread through area, continue to rise through repeated exchange, or even reach science’s potential. What changes across those positions is how far income expected ahead carries movement on the PPF.

Yet we have been scaling for decades the things that come into use as the farmer moves on the PPF, not what gives the farmer reason to move on the PPF in the first place.

In the narrow, that visibility can reach the few through repeated exchange, crop-specific scarcity, niche value chains, export access, or income paid through public support, while income stays low for the many. Where yield stays at a low settled position, income still moves for those with more land to farm. That is not scale at the level of the many. In the broad, income remains visible and keeps moving across the many. This is the record we see.

So here is the Unquestion:

The more we Unquestion, the more clarity we gain. The more we Unquestion now, the less future generations will have to.

We are not lost.
We simply avoid the turn.
Once we Unquestion, the direction is already clear.

Thank you for seeing.