USE OF SLOW-RELEASE FERTILIZERS IN PEAT SUBSTRATES

Peat substrates can be improved by adding slow-release fertilizers.
The advantages are: reduced danger of excess fertilization, better protection against nutrient leaching, regular nutrient supply, and less work in the case of top dressing.
Higher costs per nutrient unit and the possibility of excess fertilization, when not stored properly, must on the other hand be regarded as drawbacks.
In peat substrates basic dressing in the form of slow-release fertilizers can – depending on its kind of activity – amount to the double or triple nutrient quantity as compared with commonly used fertilizers.
This nutrient reserve lasts from 3 to 9 months.
The way in which nutrients are mobilized varies and depends on the characteristics of each product.
A good slow-release fertilizer should in the beginning let free as few as possible of water-soluble salts and only gradually supply the soil solution or the plant root respectively with its nutrients.

Slow-release fertilizers can be classified into different groups, according as to whether they contain hard-soluble or adsorbed nutrients or such nutrients, which are let free only, when microbial transformations or permeation through the plastic coat takes place (see table 1). Products already exist which combine several of these effects.
In the following the results of experiments concerning laboratory tests, storage conditions and plant reaction are described, which have been carried out at Weihenstephan with slow-release fertilizers now on the market.

Symposium on Peat in Horticulture

F. Penningsfeld

https://doi.org/10.17660/ActaHortic.1975.50.14