In 2019 Delphy started a planting-hole application trial in Viburnum Tinus at Tree nursery Marcel Michels located in Hilvarenbeek. Delphy is a leading internationally operating organization for research and advice in the tree nursery sector. Planting-hole applications with controlled release fertilizers are increasingly used in ornamental tree nurseries.
Partly caused by simple application through mechanization. (planting hole machinery on GPS). Increasing number of tree nurseries have invested in mechanization to reduce labour costs.
Positive experiences in plant quality are just as decisive for the success of this application. Controlled release of nutrition direct in the rootzone is the reason for this success.
Trial setup:
In this trial a distinction is made between controlled released fertilizers and soil stimulants & substrates. In the trial setup of 2019-2020 these objects have been tested separately from each other.
In this report we will focus exclusively on the results of the controlled released fertilizers as planting-hole fertilizer and a non-planting-hole application with mineral-organic fertilizers Object D.
2018
Year before trial is planted
50 tons cattle farmyard manure
Crop: Tagetes
2019
On April 17th P9 young plants “Viburnum tinus” planted in planting holes with a 15 cm diameter. Plant distance 80×50 cm. (19.047 plants / ha).
| Plant-date | Application | Gram / plant | N / year | |
| 1th | 17-4-2019 | Field-Cote CRF SMART 14+5+11+2MgO+TE 24M | 30 gram / plant | 40N |
| 2th | 17-4-2019 | Object I (coated / CRF) | 25 gram / plant | 40N |
| 3th | 17-4-2019 | Object H (coated / CRF) | 30 gram / plant | 40N |
| 4th | Mei 2019/2020 June 2019/2020 | Object D (mineral – organic) Total – 2 years, 4 applications with 160N | 800 kg / ha / year | 80N |
End results trial 9-11-2020 (after 2 years)
| Applications | Plant quality | Root quality | Average length 9-11-2020 | |
| 1th | Field-Cote CRF SMART | + | + | 98 cm |
| 2th | Object I (coated / CRF) | + | + | 92 cm |
| 3th | Object H (coated / CRF) | +/- | +/- | 89 cm |
| 4th | Object D (mineral-organic) | + | + | 90 cm |
Conclusions
This fertilizer trial shows us that we can achieve better results with 50% less N when we use plant-hole application method with Field-Cote CRF SMART 14+5+11+2MgO+TE 24M
In 2 of the 3 controlled release fertilizer plant hole applications, the results are better than standard application (not in the plant-hole) with mineral-organic (Object D) two times per year.
All objects scored well on rooting, except for Object H. (> 10% failure of plants and lesser quality rooting.)
With planting hole application, you can clearly fertilize more efficiently.
In 2021, Delphy will set up another planting-hole fertilizer application trail at Marcel Michels. This time with Prunus young plantings P9.
Hopefully we will meet during the delphy demo days this year to see the results of this interesting way of fertilization.
We grow SMART!