Concept:Every region follows different agricultural practices.Depending on the type of crop and scale of farming various agricultural practices are adopted.Explanation:About Jhoom farming:Jhoom farming is a type of shifting agriculture.It is the most common type of agricultural practice in northeast India.It is also called Slash and burn agriculture.It is a shifting cultivation practice.It is also known as fire-fallow cultivation.After cutting one crop, the land is left as it is for some years.Nothing is grown there. Forest land is cleaned and ashes are added to the soil.Cultivated spots/ areas are usually small.Short periods of crop occupation alternate with long fallow periods.In one farm different types of crops like maize, vegetables, chillies, rice can be grown.The farmer cultivates on a plot of land temporarily.When finding the land infertile to grow due to soil exhaustion, they move on to another plot.?Thus,(A) After cutting one crop the land is left as it is for some year - Correct(B) The weeds (bamboo etc.) are pulled out and burnt in the field - Incorrect(C) The ash of the weeds acts as manure.- Correct(D) When the land is ready for farming it is ploughed deeply before growing the seeds. - Incorrect