Question

how the nutrients in soil can be put back when used up

Answer 1

we can put the nutrients back to the soil by adding fertilizer and manure to them

Answer 2

When all the nutrients in soil are used up they can be put back by adding fertilizers and manures. Fertilizers and manures contain plant nutrients like nitrogen phosphorus and potassium etc. So, when this are added up to soil the soil is enriched in nitrogen, phosphorus and potassium etc.The crops can then grow well in the soil. The most commonly used which are used to provide nutrients to soil are NPK which means nitrogen (N),phosphorus(P) and potassium(K) and urea.