Question

crop rotation is done by farmer so they have different products to se
ll in the market in every season. give reason?

Answer 1

crop rotation makes the soil remain fertile for longer duration.different crops utilises different nutrients so if different crops were planted on same soil it can maintain fertility rate.the farmers to can have the advantage by selling different products

Answer 2

if a farmer grows only one crop in the year then the nutrients  required for the crop will decrease in the soil and after that the crop will not grow...it also destroy the fertility of the soil....by the crop rotation the crop will get enough nutrients one by one to grow.....

"or" ( the another answer )

farmers practice crop rotation so that the soil doesn't become deficient in certain nutrients. for example: if we grow certain crop year after year, the crop will need a lot of phosphate.....