It has been heartening to receive calls from farmers requesting further dolomite for their properties particularly so when it is some years since they last applied.
In the interim some have applied other magnesium ‘fertiliser’ the decision being made on the basis of price. The results have disappointed and the decision to return to dolomite applications is unlikely to be changed.
These farmers and growers understand that price is one aspect however the benefits received from the application is the true measure of value.
Value can only be ascertained by an appreciation of what dolomite delivers. Experience is required to fully appreciate the improvement in general animal health, the reduction in calcium/magnesium related metabolic disorders, and the ability to provide more highly nourishing clover growth over summer.
With major nutrient fertiliser at current prices an increase in the effectiveness and efficiency of applied nutrient may reduce the amount required, which is best monitored with regular soil and leaf tests.
The improvement in physical soil structures from a single dolomite application is often quite obvious. The improvement in the water absorbing ability of dry sandy soils is often remarked on. Home gardeners using dolomite in gardens exposed to the north appreciate this benefit.
Dolomite also has a unique ability to condition or soften soil compacted by animal feet particularly during periods of excessive moisture encouraging plant roots to develop deeper in to the soil.
Deeper root penetration allows the plant access to increased quantities of both nutrient and moisture. Mycorrhizae, a term meaning “fungus root”, play an important role in the ability of plants to take up phosphorus and other nutrients relatively immobile and present in low concentrations in the soil solution.
These fungi invade the plant root and a relationship develops whereby both the plant and fungi benefit. Moisture uptake may also be improved by mycorrhizae, which can extend the plant roots absorptive surface by up to ten times compared to an uninfected plant. There may also be increased protection from soil borne diseases and parasitic nematodes resulting in healthier stronger above ground growth
In return these beneficial fungi derive energy in the form of sugar direct from the plant reducing their need to compete with other soil organisms. Phosphorus is an essential element in the formation of sugars and a plentiful supply of available phosphorus helps ensure maximum sugar formation in the plant leaf providing the necessary energy for further phosphorus uptake by the fungi.
It is probable that all our pastoral soils contain mycorrhizae. Plants in soils to which dolomite is applied are able to develop roots to a significantly greater depth and in conjunction with mycorrhizae their ability to extract nutrient and moisture resulting in higher levels of total growth is enhanced.