Effects of Ca: Mg ratio and pH on soil chemical, physical and microbiological properties and grass N yield in drained peat soil
Deru, J. G., N. Hoekstra, M. van Agtmaal, J. Bloem, R. de Goede, L. Brussaard and N. van Eekeren . 2023.
Abstract
In three dairy grasslands on peat, minerals were added to
manipulate the soil Ca:Mg ratio with or without effect on pH. The
responses of soil properties and grass N yield were measured.
CaCO3 application led to higher soil Ca:Mg ratio and pHKCl
compared to the untreated control, decreased Ntotal and Ctotal,
and increased P availability. Grass N yield increased in the first
year by only 6% of the reduction in soil Ntotal, but not in the
second year. A higher pH increased SOM decomposition,
especially in soils with high P availability. MgCO3 reduced the Ca:
Mg ratio, had little influence on soil parameters and no effect on
grass N yield. In contrast, CaSO4 and MgSO4 did not influence
pHKCl but reduced grass N yield in most cases. Results suggest
stabilisation of organic matter by Ca binding in treatments with
added Ca. We conclude that grass N yield was not linked with
changes in Ca:Mg ratio but with soil pH. The pH effects on SOM
decomposition depended on P availability and Ca binding.
Hence, to avoid potentially large soil losses of C and N, the
current agricultural advice on pH management in peat grasslands
should be better adapted to local edaphic characteristics.
Key Words
Grassland; histosol; lime; gypsum; kieserite; soil quality; soil organic matter
