At least 17 elements are required for plant growth, 6 of these are required in quite large amounts and are referred to as macro-nutrients, 11 in very small amounts and these are referred to as micro-nutrients.
The vast majority of soils can supply sufficient amounts of these elements or nutrients to sustain growth, however, when grasses are removed through cutting the situation changes and nutrients must be added to the soil in various amounts and combinations if growth is to be maintained. The secret is to add the right amount.
The study of plant nutrition, to include the formulation of nutritional programmes, is a complicated matter. Different plants require different amounts and combinations of nutrients; different soils have different abilities to supply and retain nutrients; different regimes demand different inputs and the amount of inputs will vary with climatic conditions. Consequently, the formulation of a nutritional programme is a specialised job.
Golf courses, unlike agriculture, require nutritional programmes that focus on maintenance rather than production. These programmes aim to limit production of leaf growth yet still maintain the plant in a healthy state. The formulation of such a programme begins with a Soil test. It is pointless applying the same amount of nutrients each year without knowing exactly what the root zone can provide already. An agronomist knows the requirements of the plant; a soil test provides information on what can be provided by the root zone and a calculation can then be made that will result in a suitable nutritional programme.
The soil test should primarily concentrate on the levels of Phosphorus, Potassium, Calcium, Magnesium and Sulphur which should be notified to the testing body. Along with ascertaining these nutrient levels, a soil test will also show various soil parameters such as the CEC (cation exchange capacity), salinity and pH to name but a few. These reading are important as they will indicate a soils ability to retain and provide nutrients to the plant. Of these parameters PH is probably the most important in that uptake of nutrients by the plant is most efficient between a pH of 6 to 7. It is much more difficult to lower soil pH than increase it. The most important thing about regular testing is that it indicates the direction in which pH is going and will then alert the Agronomist to any changes he might need to make with regard to product usage.
The results should be filed and forwarded to the course Agronomist who can then draw up a nutritional programme in conjunction with The Course Superintendent. This should be the starting point year on year as it will ensure that the plants requirements will be met which will result in a healthier sward and better playing conditions.