Economics of farm laborers

Apparently farmers in Punjab are worrying over paucity of farm laborers. It so happens that the laborers from Bihar and UP chose to stay home due to easy money from NREGA. Good thing, it works for them you say, elevates them from poverty.

However, Punjab farm output may fail, resulting lower food output. So, we may have unwanted roads/ canals created at the cost of needed food grains. The food grains will be costly for all. Even those poor laborers may not afford it after all, even if they are elevated out of their poverty.

How about mechanization of farm work?