Practical field tests at nurseries; gaining experience with compost

21 December 2021 - Published by Hanne Lakkenborg Kristensen
In different tree nurseries in Denmark and the Netherlands, Delphy and HortiAdvise Scandinavia started practical field tests. By starting these field tests, the concerning growers gain experience with the application of compost on their fields. The tests are monitored by Delphy and HortiAdvise, were they look at the practical side of application of the compost, plant growth, root development, soil microbiome and soil pathogens. But also the plant resilience and the presence of diseases is monitored.

Prunus lucitanica

On a commercial field in Boskoop (the Netherlands), the shrub Prunus lucitanica is produced. In 2020 tailor made compost was applied on half of the field before planting. Compost was mixed with the top 20 cm of the soil. After application the young plants were planted. The first year of the plants with compost was reduced, compared to the non-treated plants. The second year, however, the plant growth of the treated plants was better: more vitality and longer shoots. By measuring the soil life, there was an increase in fungi and protozoa and a also an increase in the diversity of microbes in the soil .




Fruit tree growers experiment with compost

Fruit tree growers in the province of Flevoland (Netherlands) started with two compost demo in 2021.  With quite different objectives. In the first trial, compost is used in two year cultivation of apple trees. After two years these plants are the starting material for fruit growers. Before planting the field was divided in different treatments:

  • Practical, without compost.
  • Compost

Plants were monitored, assessing plant condition and plant growth, diameter of the stem. Also dry matter leaf analyses were taken twice during the season. Comparing compost with the non-compost treatment is showing no differences. Next year, 2022, the plants are observed again.

In the second demo, a grower is applying the compost as part of the substrate for layering the mother beds of apple root stocks. Different combinations of compost, saw meal and turf will be observed and analysed. This winter the root development of the root stocks will be measured.

In Flevoland the nurseries with the demo’s mentioned above, are part of a study group of five fruit tree growers. The group will visit the demo’s once or twice a year to discuss the results.


Compost application in Fagus and Larix with optimized compost

HortiAdvice Scandinavia started in 2021 also a demo with sown Fagus and Larix. In these cultivations different amounts of compost were applied:

    1. Sown Fagus. Incorporation of 10 and 50 tons/ hectare of compost compared with no compost before planting.
    2. Sown Fagus. Compost applied 10 tons/hectare after sowing compared with no compost.
    3. Planted Larix. Incorporation before planting of compost: 10 and 50 tons/hectare, compared with no compost.

The compost applied in these demo’s is coming from the compost firm Klintholm. One of our partners in Soilcom. The input material of the compost applied, consisted of leaf and branches.  Mainly coming from garden waste of households. By joining the Soilcom project, Klintholm changed the composting process. The input material is now shredderd and sorted. Resulting in a fine and uniform compost. Klintholm monitors the composting process by measuring temperature and moisture. While optimizing the composting process and talking with different composting experts in Soilcom, Klintholm concluded that the process needed more moisture.  Now more moisture is added. And they also work with windrows which are turned two-three times a year.

The experiences from the trial and the optimized composting process, as well as the results are shared with the Danish growers.