Can zinc deficiency in soils be treated?
Once identified, zinc deficient soils can be easily treated with zinc fertilisers to provide an adequate supply of zinc to crops. Several different zinc compounds are used as fertilisers but zinc sulphate is by far the most widely used material. Zinc sulphate is most frequently broadcast (or sprayed as a solution) evenly over the seedbed and incorporated into the topsoil by cultivation before sowing the seed. One application of between 20–30 kg ha–1 of zinc sulphate will often have an improving effect on the zinc status of the soil which will last for around five years before another application is required. However, this will vary in different areas; in some of the most deficient soils, such as those with a high content of calcium carbonate, zinc applications may have to be larger and more frequent. Placement of the zinc fertiliser below and to one side of the seed at sowing is also frequently used. In this case, lower application rates are used because of the close proximity of the f
