Peter Burton
Functional Fertiliser
The closure of the superphosphate manufacturing plants here in New Zealand is ongoing. They are old and the cost of upgrading to meet modern environmental standards will become prohibitive. They are a relic of the days when high quality rock from Nauru and Christmas Island was available at low cost. Pastures responded positively, Britain was a guaranteed market for farm produce, and lowest cost per unit of nutrient was a sound philosophy.
Times have changed. Pastures no longer respond as they once did and the demand for soluble phosphorus will necessarily decline to meet true maintenance. The replacement for superphosphate is soft phosphate rock. Phosphate rock suitable for direct application to pasture contains around 30% calcium, much the same as ag.lime. Research shows the speed at which phosphorus is released is dependent on the demand for calcium. The reason calcium is essential is that all beneficial soil biology is stimulated by a steady supply of plant available calcium.
Research on lime and its positive effect on the activity and population of earthworms is well documented. Where beneficial earthworms thrive so do all other beneficial soil dwellers including fungi and bacteria. The Olsen P test measures around 5% of total soil held phosphorus. Additional Resin and Total P tests are required to better ascertain the true phosphorus status. The rate at which phosphorus moves from less available sites to become plant available is dependent on soil biology. The ideal air content of soil is 25% and intensively farmed pastures seldom contain that amount. This negatively impacts pasture growth, and the common response is to apply synthetic nitrogen.
Synthetic N speeds the removal of calcium and beneficial soil biology declines. It’s a steady downward spiral resulting in what is now recognised as an overall 20% decrease in annual pasture production since the late 1980’s. Accepting that soil fertility is calcium, not phosphorus, driven is essential. Extra clover growth is stimulated resulting in more nitrogen being fixed reducing the necessity for synthetic nitrogen.
Clover is higher in calcium and energy than grasses which is why animals fatten more quickly and milk production increases when animals graze clover dominant pasture. For over twenty-five years top performing intensive grazing and dairy property owners have relied on CalciZest and DoloZest as the foundation of their farm performance. CalciZest contains high quality lime along with soft carbon inoculated with a wide range of beneficial soil biology. Where magnesium is required DoloZest containing the same soft carbon and microbes with the lime content replaced by Golden Bay dolomite is applied. Phosphorus, sulphur, potassium and trace elements are added as required to ensure a total nutrient package.
Autumn and winter are the ideal times to apply as pasture growth is often restricted by the build-up of dung, old root matter and litter on the soil surface. Digestion always comes before growth and winter is the naturally designated digestion period. Applying now ensures spring production is maximised. Increased growth also lifts feed quality as greater leaf surface area builds extra energy, a must for all animals in spring.
For more information call Peter on 0800 843 809, or 0274950041.
