Spreading manure and fertilisers keeps the soil rich in nutrients so that crops can grow to their fullest. To keep the soil fertile, a number of critical nutrients are required, many of which are naturally found in soil. The chemical composition of soil varies depending on a range of factors, including the environment and the types of crops previously grown there. Manure and fertilisers can be used to rebalance soil that’s been depleted of chemicals and give crops an added boost.