BALANCED FERTILISERS.

New Zealand Herald, Volume LX, Issue 18496, 5 September 1923, Page 12

BALANCED FERTILISERS.

Money spent on fertilisers is often not laid out to the best advantage, because the ingredients bought in the fertiliser are not in suitable proportions. If a farmer buys a fertiliser containing more of one ingredient than is requisite for the crop and not enough of another, then ho wastes his money. The three important plant-foods— phosphates and potash—should all bo present in an available form for most crops, excepting, of course, in special cases, such as for top-dressing. Should the grower apply a superabundance of nitrogen or potash and not a sufficient supply of phosphates, or plenty of phosphates, and neglect potash, then he must not expect a satisfactory crop. Each ingredient has its own part in building up the plant to perform. Unless there is a reasonable amount of certainty from _ actual experiments that there is a- sufficient supply of potash ; and phosphate in the soil it is best to use a complete and well-balanced fertiliser. Soil analyses are not a really reliable guide . because the chemist cannot indicate, with precision what percentage, .of the plant food in the soil in a natural stato is available. It is scarcely possible for the chemist to do so. because plants differ in their capacity to take up plant foods. Clay soils invariably possess more or less potash, yet experiments have demonstrated that the addition of potash salts to clay soils has proved most useful. This arises from the fact that the potash naturally in a clay soil has not been rendered available by the processes .& which gradually break up the soil particles, setting free the important ingredient necessary to plant growth. '