They can plant trees to provide organic matter from leaves, hold the soil and provide shade and shelter for the soil add fertilisers add lime to improve the pH. add organic matter like manure, compost or mulch rotate crops and include a legume to make nitrogen available to plants plant trees to halt soil erosion leave stubble of crops after harvesting to reduce soil blowing away add earth worms make sure they don't pollute the soil with dangerous chemicals don't compact soil or destroy its structure. Using Fertiliser to Improve the Soil Farmers can apply fertiliser to the soil. The fertilisers they use mainly contain phosphate, sulphur, potassium and nitrogen products, because they are the nutrients New Zealand soils are naturally deficient in. If a farmer uses too much fertiliser it may end up in waterways, streams and ponds and cause excessive growth of water weeds. It is also expensive.
Some farmers use experiments to work out how much fertiliser to apply.
They can keep yearly records of the amount of fertiliser they applied and the grass and crops produced test the soil to find out how much phosphate, sulphur and potassium the soil has and calculate what they will need to apply experiment with using more or less fertiliser, on small pieces of land. Fertiliser Investigation Examine a range of fertiliser packet labels. Work out what the fertiliser contains. Find out where the fertiliser comes from and how it is produced. You may find your fertiliser has an NPK rating.