Wheat generally take 120-150days from sowing to harvest. Add this to 10-12 days for field prepration before sowing and 2-3days for harvesting and another couple of days for clearing the field from husk (bhoosa) in common language.
So around 135-165 days depending upon late sowing or early sowing for most common farming, in highly mechanized farming where u use machine to harvest and husk is not a prepared you can save 2-3 days at max as no machine can prepare your field early as it depends upon weather.
This is the normal time for wheat, if u do farming as u claim u would have known these things. A lot depend on farmer as it is labour intensive at the time of harvest and sowing. You can't just add 2+2 they are in no hurry beside land need little rest to gain fertility unless u are hell bent on destroying it by blatant use of fertilizers only. The only time field are empty, where we get two crops a year is after wheat harvesting, that time people sow zaid crops like watermelon.
My family have never grown paddy in my serving memory so no idea about it, it's even more labour intensive at the time of sowing but we grow wheat every year and a lot of it though I have very little part in it from past few years.
Talking about 3 crops a year makes no sense when we can barely get 38% of agricultural land under 2 or more crops a year. 60% agricultural land get only one crop a year due to lack of irrigation. Very small land holding among majority of farmers is another issue.
We do 3 crops a year all the time.
Wheat, potatoes and then millet. Tough on land but doable. @vstol Jockey