Because without rain there is no crop at all. Varuna is hailed as 'O sender of rain and the dewfall' and thanked for two things in particular: 'Thine is the mercy that cherished our furrows, / Thine is the mercy that fostered our grain.'
- Rain softens the furrows so that the plough can work and the seed can take root.
- Rain feeds the standing crop through the growing season — it 'fostered', that is, raised and nourished, the grain.
- In return the farmers offer 'the wealth of our valleys, new-garnered and ripe' — the harvest that rain made possible.