Articles
WASTE PAPER – A SUBSTITUTE FOR PEAT IN HORTICULTURE (REFEREED)
Incubation experiments were carried out to define the nitrogen status of the paper medium.
Additional investigations dealt with the chemical and physical properties and were followed by plant experiments.
First results indicated diminished plant growth in pure paper substrate.
This could be attributed mainly to the pH level, which was too high, and to the poor water conductive properties of the paper medium.
Furthermore, the amount of additional nitrogen needed was difficult to predict during the cultivation.
Based on this experience, composting trials were started to overcome the N-immobilization, to lower the pH level and to improve the water conducting properties.
Best results could be obtained with the addition of about 700 mg N/liter, preferably as ammonium sulfate.
Although much better results could be obtained with the composted waste paper pre-treated that way, a reduction of plant growth remained at the beginning of the cultivation.
Plant analysis clearly indicated phosphorus deficiency.
Supplementary phosphorus added to the raw material strongly promoted the composting process and resulted in optimum properties of the waste paper compost as a peat substitute.