ARCHIVE: Fertiliser Manual (RB209)

Fertiliser use for Fruit, Vines and Hops

Soil sampling for pH, P, K and Mg

The results of a soil analysis will only be meaningful if the sample is taken in the field in the correct way and analysed in the laboratory using recognised analytical methods. Recommendations in this Manual which are based on soil analytical data are applicable only if the specified methods of sampling and analysis have been followed. In general, laboratory analysis is accurate and the main source of error is when taking the soil sample in the field. Soil analysis results from badly taken samples may be misleading and can result in expensive mistakes if wrong fertiliser decisions are made.

The procedure for sampling arable, vegetable, fruit and grassland is given in Appendix 3. The following modifications should be adopted when sampling fruit, vines or hops.

Sampling before planting

Fields intended for planting should be sampled at 0-15 cm and 15-30 cm soil depths. This is particularly important on land previously in fruit, vines, hops or grass where a depth gradient in nutrient content and acidity will probably have developed. The 15-30 cm sampling is not essential on land that has been ploughed regularly to a depth of 25 cm or more. An even depth of sampling is important, and both the top and bottom portions of the soil core should be included in the sample.

Sampling should be carried out before ploughing so that if lime and fertiliser is needed, it can be applied and then ploughed down. In old herbicide strip orchards, separate samples should be taken from the grass alley and the strip, especially where previous lime and fertiliser applications have been applied to the strip only.

When sampling fields where there is a risk of soil acidity, each core should be tested for pH in the field. Soil analysis of a bulked sample will not necessarily identify acid patches within the field.

Sampling established crops

For all established crops, representative samples should be taken every 3-5 years from the 0-15 cm depth (Appendix 3) but with the following qualifications.

  • Orchards in overall grass management or very weedy orchards should be sampled within the spread of the tree branches.
  • In orchards with herbicide strip management, sampling should be restricted to the strip, excluding the grass area.
  • Samples from soft fruit plantations and hops should be taken at random from within the area of rooting.
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