30 march 2017
Together with certified companies, RHP is continuously researching, aiming for more knowledge. Currently, research involving organic fertilizers is carried out. What are the first experiences from this collective research? The interim score…
Earlier in the research it appeared that the pH of a substrate increases by mineralisation of organically bound nitrogen in organic fertilizers to ammonium.
When the pH value increases to over 6,3 then ammonium can partly turn into ammonia. This is not desired and is harmful to the plants. Every substrate has a certain pH buffer. Because of this buffer the pH changes less quickly in case of adjustments. At the moment it is further examined what the effect of the pH increase into substrates with
different pH buffers is. In the research it is especially examined what the course of this process is and to which extent plant harmful concentrations ammonia really develop. From the first results it has appeared that substrates with a smaller pH buffer show a stronger pH increase. These substrates bear more risk of the development of ammonia.
In a test set-up in the laboratory, RHP now measures how much ammonia is developed at a high pH. In the measuring set-up a continuous air flow is led through the samples. When ammonia arises, it is picked up and collected in a hydrochloric acid solution. In a next phase of the research it is tested when dangerous concentrations for plants could develop.
Figure: pH course of mixtures with organic fertilizer during the release test.
A. substrate with a pH buffer of 23 meq/pH point.
B. substrate with a pH buffer of 7 meq/pH point.
The researching of organic fertilizers will be finished in the first half year of 2017, after which the results will be discussed with the certified companies concerned. The research report will then be provided through My RHP. As knowledge center for substrates RHP has
performed research of potting soil and substrates for over 30 years. Also together with the certified companies, that gain from continuous knowledge development and further improvement of their insight of raw materials as a result of collective research.
