Need I use iron shovel or just wood or stone shovel is ok?And if I use machine (not robots)that I can let the food seed to food but I needn't do it by hand?
You can use any kind of shovel.
I do not quite get what you're trying to say with your second question.
You can make robots carry Cereal to the Threshing Machine. That will create Straw and Cereal Seed. They can then plant the seed for more