The surplus of a farmer's output over and above his own family's consumption, which he can sell in the market, is called:

Marketable surplus is the part of a farmer's total produce that is left after meeting his own needs and is available for sale in the market. It is worked out as:

Marketable surplus = Total production – (family consumption + seed for the next crop + feed for animals + payments in kind to labourers, artisans and landlords + wastage).

The part that the farmer actually sells is called the marketed surplus. It can be more than the marketable surplus when a poor farmer has to sell even what he needs, to repay debts or meet urgent expenses, and buys grain back later at a higher price; this is called distress sale. It can be less when the farmer stores some produce to sell later at better prices.

Marketable surplus is very important for the economy. Growing towns and industries need food grains and raw materials from rural areas. In India, the Green Revolution of the late 1960s greatly increased the marketable surplus of wheat and rice, especially in Punjab, Haryana and western Uttar Pradesh. This allowed the government to buy large quantities at the Minimum Support Price (MSP) through the Food Corporation of India (FCI), set up in 1965, and build buffer stocks for the Public Distribution System.

Large farmers usually have a larger marketable surplus than small and marginal farmers, who consume much of what they grow.

Why not the other options?

• ✗Consumer surplus is the difference between what a consumer is willing to pay for a good and what he actually pays; the idea was developed by Alfred Marshall.
• ✗Producer surplus is the difference between the price a producer receives and the lowest price at which he would be willing to sell.
• ✗Buffer stock is the stock of food grains kept by the government (through the FCI) to ensure food security and stable prices.