In situ compost and Best Farming Method
Hello Radha,
As Mr Vinod said, in situ compost is one of the best method which allows the land keep more organic matter and remain fertile land forever. I consider burning the remainings (biomass) after the season is crime. Keep in mind you land is your only resource, keep your land live first and balance you can either use it for cattle feed or renewable energy, but just dont burn.
Check your water and land quality first before you proceed.
There are so many variety of farming practise are available now for farmers. Do not do conventional flood irrigation method which will be another waste method, because 1) more water will be spend 2) more electricity will be used to pump the water 3) there will be more run off of water and fertilisers 4) pan evaporation will drink some amount 5) may be more wastes which I cant figure out. You may try any one or combination of methods of farming :
1) Drip irrigation - which will apprently change your dry land as one of the cultivable land. Your water source for 4 acre is enough to cater 10 acre drip irrigation.
2) Raised Bed with drip irrigation method - which may be more suitable for your dry land.
3) If you can afford - send your brother training for greenhouse cultivation and go for small area initially.
Choice of plant variety absolutely depends on how you can market that produce in your area, how perishable that produce, how long you can store that produce,etc. all matters for you to decide first.
Good luck,
VS