Soil Organic Matter Quality in Soils With Different Levels of Manure Fertilisation

Soil organic matter (SOM) significantly affects the growth, development and yield of cultivated plants. In the era of increasing agriculture intensification and adverse changes in the crop structure as well as climate change, it is important to know the processes affecting the accumulation and degradation of SOM. This paper aims to assess the quality of organic matter in Stagnic Luvisol fertilised with bovine manure to varying degrees. Soil samples were taken in spring from topsoil after pre-sowing treatments. Three soil profiles were selected: soil fertilised with manure annually at a dose of 30 t ha⁻¹, soil fertilised with manure every 4 years at the same dose and soil deprived of organic fertilisation in the past several years. The following laboratory analyses were performed (soil pH, total carbon content). Sequential fractionation of organic matter was carried out based on the Schnitzer method. In humic acid preparations, the elemental composition (CHNO and H/C ratio) was determined and spectrophotometric properties were measured. The conducted tests revealed a significant impact of manure fertilisation on the quantity and quality of organic matter. In the soil fertilised with manure annually, a much larger amount of SOM was found with a greater share of labile forms. In addition, humic acids extracted from the soil were characterised by lower maturity as well as molecular weight and condensation of the aromatic part of their structure.