Changing Fertiliser World

Changing fertiliser world

With recent massive price increases in traditional fertiliser products containing nitrogen, phosphorus, potassium, and sulphur, there are now two words that should be foremost in the mind when deciding on any fertiliser product, effectiveness and efficiency.

Before getting to this point, the best operators will know what element or elements are required for their property and what response they are likely to receive. To not have this basic understanding may mean relying on people who have a focus on a single product or limited product range, and they may not have their client’s best interest as their focus.

To establish the fertiliser requirements of a property for this coming season information is required, and best decisions are based on good information. Historical information, soil and herbage tests, along with accurate records of past fertiliser inputs are valuable.

Physical examination of the soil also provides important information and often the areas where the soil is softest grow the most. This is because grass is able to send roots to 0.5m and lower provided the soil is sufficiently friable and soils contain significant amounts of nutrient and moisture in this zone.

A farm walk with a spade will provide much information. It does not take long to be able to feel the hardness of soil simply by walking over it. A quick dig with a spade will confirm what can be felt and a hard layer preventing root development is easily seen.

Soil tests are only accurate within quite broad parameters and an Olsen P test of 25, for example, simply means that if the same site was retested, 9 out of 10 times the test result would fall between 15 and 35, and the other time it would be outside this range.

The collection of a large number of cores reduces the likelihood of extreme variation and on a large area the collection of around 100 cores into a bucket, which when well mixed and a portion taken will provide a useful result.

Time of testing is also important as nutrient levels fluctuate throughout the season depending on plant demand, moisture and temperature. Autumn, when soils are sufficiently moist for strong growth is a useful time to test.

Pasture leaf testing can provide valuable data, however it is important to have a purpose for testing. Long autumn saved pasture will have far higher nutrient content than rapidly growing pasture in September. Bright sunlight, time of day, and quantity of clover or other plants in the sample all have an affect on the result. 

If the purpose of testing is to check nutrient availability for maximum production a ‘clover only’ test may be best.

To then formulate a fertiliser plan from the various pieces of information requires careful interpretation. Finding someone that has a genuine interest in your situation, has good field experience, and sound fertiliser knowledge can take some time, however those people do exist.

It is essential that the person you choose to work with is someone you can relate well to. Do not be afraid to keep asking questions, the time of; “it’s what everyone is using” and “more is better” are over.

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