Question

why do we need to irrigate fields well before sowing seeds

Answer 1

We irrigate fields well before sowing seeds because
It maintains moisture in the soil due to which seeds can germinate.
It is essential for the growth of the roots of the crop plants as roots of the plants do not grow well in dry soil.
It is necessary for the absorption of mineral nutrients by the plants from the soil.
Water supplies two essential elements hydrogen and oxygen.

Answer 2

we have to irrigate the field before sowing seeds because, germination of seed does not take place under dry conditions and other reason is to make tilling easier