LEACHING OF NUTRIENTS FROM CONTAINERS WITH NURSERY PLANTS

In The Netherlands large amounts of fertilizer are commonly applied to nursery crops grown in pots.
To design a more efficient fertilization system to reduce waste of fertilizers and environmental pollution, trials were carried out for three years with three different crops and with fallow pots.

At the start of the growing season the N, P and K contents of the substrate were high as a result of the basal dressing given.
Then a reduction in the amount of nutrients in the potting soil occurred, followed by a gradual increase due to weekly topdressings of 20 g NPK-fertilizer per m². In the drainage water the same pattern, although less consistently, was found.

The amount of leachate on a given day was strongly correlated with the amount of rainfall on that day.
The correlation was not improved by including the amount of rain that fell during preceding days.

In a model the daily amount of leachate was simulated depending on rainfall and evapotranspiration, which was a fixed proportion of the potential evaporation or dependent on the water content of the substrate.
For a certain period, a given quantity of rain in the form of a few heavy showers causes more leaching of water than the same quantity in the form of lighter, more frequent showers.

International Symposium on Substrates in Horticulture other than Soils In Situ

J. van der Boon, H. Niers

https://doi.org/10.17660/ActaHortic.1984.150.24