Fig.3 Relationship between RY and OlsenP for data from treatments with soluble P fertiliser
Olsen P. and Pasture Growth
13th August 2005 11:50AM
"There was no evidence that relative yield increased with increase in Olsen P test values above 20, ......."
This is one of the conclusions of a report published by AgResearch scientists in the NZ Journal of Agricultural Research 1997, Vol40. Pasture yields were measured on many sites around NZ over six years, to examine the relationship between Olsen P and pasture dry matter (DM) yield. This report clearly contradicts phosphate sales hype that encourages ever higher levels of Olsen P.
Notice on the graph that an Olsen P of just 10 will allow pasture growth to reach about 90% of potential and about 98% of potential is reached at an Olsen P of 20. It is obviously inefficient to apply P fertilisers to soils with an already high Olsen P. Farmers should look to achieve better efficiency of P uptake through managing soil pH, improving soil structure and root depth. Frequently, herbage tests will show that P is not the nutrient in least supply.
Clovertone is a growing company based in the central Waikato town of Kihikihi. We have been in operation now for over 4 years. What is Clovertone? Clovertone is the result of extensive research conducted over the past 5 years, to improve clover vigour and persistence. Clovertone contains plant extracts and nutrients that strengthen the clover plant and roots, and increase it's resistance to pests and diseases such as nematodes and the clover root weevil.
The main reason farmers apply phosphate and potash fertilisers is to grow vigorous clovers, which delivers nitrogen to the rye grass. With adequate nitrogen, rapid grass growth leaves the clovers struggling to compete for the available nutrients. In an endless struggle for dominance in a pasture sward, strong grass means weak clover, which in turn means weak grass, which allows the clovers to recover again.
If we stack the cards against the clovers with urea applications, and new pests, we end up in an expensive downward spiral of ever increasing urea applications and fertiliser costs along with steadily weakening clover growth. There is no sense in applying expensive fertiliser mixes which are designed to help clovers compete against the rye grass when you have only patchy, tired looking clover in your pasture sward. The way to escape this costly downward spiral is to foster your clovers with sensible applications of fertiliser, nitrogen if necessary, and Clovertone to tip the competative balance back in favour of the clover. It's all about competition for the available nutrients. Clovertone gives your clovers a fighting chance.
