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
