What India grows, and what the state buys.

A quintal is 100 kg, so a support price of ₹2,000 a quintal is ₹20 a kg. The line multiplies the year's national average yield by that price. It is the most a farmer on an average hectare could have earned from wheat at the support price that year. It says nothing about costs, about farms smaller or less fertile than the average, or about farmers who sold to traders at lower prices.

Each point is a whole crop year, both seasons. The dips are droughts: 1965-66 and 1966-67, 1979-80, 1987-88, 2002-03 and 2009-10 were all years of a failed monsoon. Population grew too, so grain per person rose far less than the line; this chart is the total.

The four panels share one scale, so their heights compare directly. Wheat took off after the high-yielding varieties of the mid-1960s, the Green Revolution, first in Punjab, Haryana and western Uttar Pradesh. Pulses, grown mostly on unirrigated land, barely moved for forty years before rising in the last decade.

Yield is the harvest divided by the area under the crop. It rises with better seed, irrigation, fertiliser and timely sowing, and falls with a bad monsoon, pests or heat at the wrong moment. The state charts further down show how far yields still differ inside India: the same land could feed more.

A hectare that carries two crops in a year is counted twice, once in each crop's area. The fall in coarse cereals is the story of millets: as irrigation spread, farmers moved to rice and wheat, which the government buys at a support price, and to cash crops.

Each panel has its own vertical scale: read the shape, not the height against a neighbour. Oilseeds are nine crops together (groundnut, rapeseed and mustard, soyabean, sunflower, sesame, safflower, niger, castor and linseed). India still imports more than half of the edible oil it eats; the domestic harvest is one side of that.

An index of 150 means production half as large again as in the base years. On the newest base, fruits and vegetables, plantation crops and spices carry weight alongside grain, so the all-crops index can rise when grain is flat. Compare growth within one line; never read one base's level against another's.

The gap between gross and net sown area is land that carries a second or third crop in the year, usually because it has water in winter. Cropping intensity, gross over net, is the measure of that. Most irrigation is groundwater from tube wells, which is why water tables in Punjab, Haryana and Rajasthan keep falling.

This is the weight of nutrients, not of the bags: a 45 kg bag of urea holds about 21 kg of nitrogen. Urea is sold at a fixed, heavily subsidised price, so farmers use far more nitrogen than phosphate and potash; agronomists recommend a balance closer to four, two and one. The state chart further down shows how unevenly it is spread.

Kharif prices are announced around June for the crop then being sown; wheat's in October for the crop sold the next spring. In a few years the price includes a bonus the RBI's notes record (wheat in 1992-93, 1993-94, 1996-97, 2005-06, 2006-07 and 2010-11; paddy in 2006-07 and 2007-08). Paddy is priced as paddy, before milling: about two-thirds of its weight becomes rice.

Where a bar stands above the line, the support price rose faster than the cost of living of a farm labourer's household that year. That says nothing about the cost of growing the crop: seed, fertiliser, diesel and hired labour. The Commission for Agricultural Costs and Prices estimates those costs state by state, but the RBI's tables do not carry them, so this guide cannot show the margin. We do not know from these tables whether farming a quintal became more or less profitable.

Raising the price of oilseeds faster than that of rice and wheat is one way the government has tried to pull farmers towards crops India imports. Pulses, another import, were given rises close to those for paddy and wheat. A price only works where someone buys at it: the government buys pulses and oilseeds in much smaller amounts than rice and wheat.

Procurement is grain bought at the support price, mostly from Punjab, Haryana, Madhya Pradesh, Chhattisgarh, Telangana and Andhra Pradesh. Off-take is grain released from the pool, mainly to ration shops, where about 80 crore people are entitled to grain. The spike in 2020-21 to 2022-23 is the free grain of the pandemic schemes, which RBI's note flags.

The buffer norm is the stock the government wants on hand for the ration system and emergencies; it differs by quarter, lowest in April, before the wheat is bought. Stock far above the norm costs money to store and can spoil; stock near or below it leaves little grain to release when market prices jump. Total stocks include small amounts of coarse grains. Before 1972-73 the RBI's table prints figures whose unit cannot be read; they are left out.

Read across a row to see what a state grows, and down a column to see who grows a crop. The shares are of the national total, which includes the union territories, so a column sums to a little under 100. A state's large share can come from size (Uttar Pradesh), from irrigation (Punjab) or from a crop suited to its soil and rain (cotton on the black soils of Gujarat and Maharashtra).

When Chhattisgarh was carved out of Madhya Pradesh in 2000 and Telangana out of Andhra Pradesh in 2014, the parent state's figures changed meaning overnight. The pale line is the old, larger state; the dark line the smaller one that remains. A drop at the seam is the map changing, not the harvest.

The gap is mostly water and assured purchase: almost all of Punjab's wheat and rice is irrigated and bought by the government at the support price, while much of the rice in Assam, Odisha and Jharkhand depends on the rain and is sold to traders. Higher yields in the north-west also come with heavier use of groundwater and fertiliser.

Per hectare figures follow irrigation and crop mix: irrigated rice and wheat take far more fertiliser than rain-fed millets or pulses, and the hill and north-eastern states, where much farming is organic by default, use very little. A high figure is not the same as good practice; overuse of nitrogen wastes money and leaches into groundwater.

Dots to the left had a dry monsoon; dots low down a smaller harvest than the year before. The crop year 2002-03 lines up with the monsoon of 2002, its kharif season. The link is loose: a dry June can be made up in August, irrigation has grown, and a good harvest the year before makes the next one's change look worse. A gridded estimate of rain over the whole country is not the farmer's rain gauge.