Optimized soil conditions and higher yields by long term use of organic matter sources

14 April 2023 - Published by Hanne Lakkenborg Kristensen
Written by PSKW and Esther Hessel

Since 2006 PSKW is carrying out a long term trial with applications of organic matter sources in vegetables: mushroom manure, green compost, vegetable, fruit and garden waste compost and farm compost. Every two years these organic matter sources were applied. 10 tons per hectare organic matter was the starting point for calculating the doses of the different sources. 

In SOILCOM the characteristics of the soils of the different treatments, as well as the yield of the crops (Savoy cabbage in 2020, beetroot in 2021 and green Sellery in 2022) were measured.  It is clear that the long term use of organic matter sources has large benefits. And these are even larger in the near future, as summers become dryer. And the rain showers become more intensively in some periods.

The measurements is 2020, 2021 and 2022 showed that the infiltration rate (mm/h) increased by using organic matter, compared to the Blanc. Water infiltrates better in the soil and becomes available for the plants, instead of running of the field. Also the soil moisture content of the organic matter treatments was higher.


Increased mineralisation

The long term use of organic matter also leads to an increase in mineralisation.  The different treatments vary in the nitrogen content. This, in combination with the different weather conditions in the years, resulted in differences in measured nitrogen. In the beetroot in 2021 no starting fertilization was applied, but after 8 weeks 60 kg N per hectare was used. In the savoy cabbage in 2020 and green Sellery in 2022, no extra fertilizer was needed. On the contrary, the vegetable, fruit and garden waste compost showed at the end of the season a nitrate residue of 85 kgNO3-N/ ha, which was above the limit value.


Increasing mycorrhizae

In 2020 also a PLFA was carried out in the different treatments. All the treatments with organic matter, showed an increase in mycorrhizae, compared to the Blanc.


Yields increase by using organic matter

In the fields with organic matter application, higher yields were seen in savoy cabbage, beetroot and green Sellery.  Farm compost and mushroom manure treatments showed higher total yield in beetroot. Farm compost leaded to a significantly higher yield in savoy cabbage, compared to green manure and vegetable, fruit and garden waste compost and mushroom compost.


The measurements in 2020, 2021 and 2022 in the long term field trial at PSKW, showed the importance of adding organic matter sources to the fields leading to improved soil quality and higher yields. In general, comparing green compost, farm compost, vegetable, fruit and garden compost and mushroom didn’t lead to significant differences. In some cases farm compost showed higher yields.