Agriculture & Economic Dev

Land Productivity ($Y/A$) measures crop yield per hectare of land (raised via seeds, water, and fertilisers). Labour Productivity ($Y/L$) measures value added per agricultural worker—which determines actual farmer income and living standards. Because $Y/L = (Y/A) \times (A/L)$, even if yields ($Y/A$) rise, per-worker income ($Y/L$) stays low if too many workers remain crowded onto tiny plots (low land-per-worker $A/L$).

Marketable Surplus is the theoretical residual output left with the farmer after meeting genuine on-farm needs (family consumption, seed, livestock feed, wages in kind). Marketed Surplus is the actual quantity sold in the market. For marginal farmers facing debt, Marketed Surplus often exceeds Marketable Surplus ("distress sale"—selling grain immediately after harvest and buying back food later).

In W. Arthur Lewis's (1954) model, surplus agricultural labour is smoothly absorbed by a labour-intensive modern manufacturing sector until the "Lewis Turning Point" is reached. In India, capital/skill-intensive growth meant output shifted to Services while ~45% of labour remained trapped in low-productivity agriculture and informal construction.