Yield farming (also called liquidity mining) is the practice of strategically deploying cryptocurrency across multiple DeFi protocols to maximise returns earning trading fees, lending interest, and protocol token rewards simultaneously. At its peak in 2020-2021, yield farming offered extraordinary APYs that attracted billions into DeFi but also created significant risks and contributed to several protocol collapses.
THE DeFi SUMMER ORIGIN
Yield farming was popularised in June 2020 when Compound Finance began distributing COMP governance tokens to users of its lending protocol proportional to their activity. Suddenly, borrowing and lending on Compound also earned COMP token rewards on top of interest, creating dramatically higher effective yields. This "liquidity mining" model was rapidly copied by dozens of protocols. Total DeFi TVL grew from under $1B to $10B in months.
HOW YIELD FARMING WORKS
A yield farmer might: Deposit USDC into Aave → earn lending APY + AAVE token rewards. Take the aUSDC receipt token → deposit into Curve Finance → earn trading fees + CRV token rewards. Take the Curve LP token → stake in Convex Finance → earn additional CVX token rewards. This "stacking" of multiple yield sources on the same capital base is the essence of yield farming strategy.
YIELD SOURCES IN DEFI
Trading fees: AMM protocols share swap fees with liquidity providers (0.01-1% of each trade).
Lending interest: Borrowers pay interest that flows to suppliers.
Protocol token emissions: New governance tokens distributed to users as an incentive to attract liquidity, often called "liquidity mining."
Staking rewards: Lock protocol tokens for additional rewards.
KEY RISKS
Impermanent loss: LPs in AMM pools lose value when prices diverge, as detailed in the Liquidity Pool entry.
Smart contract risk: Complex strategies across multiple protocols multiply smart contract attack surface.
Token inflation: Protocol token rewards lose value rapidly if emission rate exceeds demand.
Liquidation risk: Leveraged yield farming can be liquidated in a market downturn.
Regulatory risk: Yield farming income is taxable as ordinary income in India at 30% + 1% TDS.
SUSTAINABLE YIELD VS. UNSUSTAINABLE YIELD
Early yield farming offered 1000%+ APYs funded entirely by token emissions, effectively paying farmers with newly printed tokens that rapidly inflated and lost value.
Sustainable DeFi yields are generated from real economic activity: trading fee revenue, lending spread, and legitimate protocol token distributions backed by genuine usage.