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Potassium Application Could Benefit From GPS Technology

Thursday, 12 April 2001


 

Precision farming techniques will continue to develop as farmers begin to harness the benefits of technology. One example is the possible future use of global positioning systems (GPS) which, new research suggests could markedly improve the efficacy of fertiliser use on hill country.

A recent study has investigated the traditional belief that hill country reserves of available potassium are sufficient. Two key findings point to the increased importance of precision farming techniques. The findings point to the future use of technology such as GPS to allow more precise fertiliser placement and changes in soil sampling techniques to more precisely identify variations in potassium levels within small areas.

The study was partly funded by Fert Research and undertaken by Professor Russ Tillman and PhD student Sally Officer, of Massey University. Their findings suggest that the fertility of hill country soils is more complex than first thought.

Hill country farmers, aerial top dressers and farm advisers may all need to use GPS technology to improve the precision of fertiliser placement, and maximise farm production potential, in the future.

Dr Hilton Furness, Technical Director, Fert Research, says the use of technology is something which will impact on farming more and more.

“We are yet to realise the full benefits to agricultural farming from the use of technology. Farmers of the future will be more easily able to farm in a sustainable and profitable way due to technological advances,” says Dr Furness.

The study showed that a hidden potassium deficiency may be developing due to the transfer of potassium by grazing animals from hill country slopes to flatter areas. The distribution of their dung and urine is not random, as it is on flat land. The sheep graze large areas but rest and sleep at well-defined, flat sites, transferring potassium in the process.

Other factors influencing potassium transfer are runoff of rainfall from steep slopes to hollows, greater grass growth on warm, north facing slopes and erosion.

The study found that potassium transfer is one of the factors in hill country that can result in pasture growth differing from 300-400% between areas.

Professor Tillman says farm advisers may soon need to reconsider how they make use of soil tests.

“The high degree of variability within very small distances sheds doubt over the interpretation of results from conventional sampling techniques. No matter how carefully a soil test is done, it is still only one factor within the whole spectrum of soil fertility”

Farm advisers and fertiliser applicators need to develop new application strategies, such as that offered by GPS, which allow for the precise placement of fertiliser in areas shown to be deficient.

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