Plan allocation in agriculture and irrigation as percentage of total plan outlay was highest in :

The First Five-Year Plan (1951–1956) allocated the highest percentage of its total outlay to agriculture and irrigation compared to any other plan. Launched in the aftermath of Independence and Partition, the plan prioritized food self-sufficiency and agrarian development to tackle acute food shortages.

• The First Plan allocated approximately 31% to 37% (including power) of the total outlay to agriculture, community development, and irrigation.
• In contrast, the Second Five-Year Plan (Mahalanobis Model) shifted the focus toward heavy industrialization, reducing the relative share of agriculture.
• Subsequent plans, while increasing absolute spending, never matched the First Plan's specific proportional emphasis on the primary sector.

Therefore, the First Five-Year Plan remains the period where agriculture and irrigation received the highest percentage of total plan allocation.