Carbon sequestration and its dynamics in water-stable aggregates

Abstract

Sequestration of organic carbon in soils is an effective strategy to mitigate global climate change. Carbon sequestration leads to an increase in carbon stocks in soil, thereby reducing greenhouse gas emissions while improving soil quality and crop production. There are several published articles containing information in which the authors explain carbon sequestration in different soil types under different climatic conditions or farming systems, but on the other hand there is less information about carbon sequestration in water-stable aggregates. In field experiment, the manner in which different soil management practices influence carbon sequestration and its dynamics in water-stable aggregates was studied. We evaluated the soil samples taken from Haplic Luvisol (Dolná Malanta - Slovakia) from all treatments of tillage (conventional, minimal and grassland) and fertilisation (without fertilisation, crop residues together with NPK fertilisers and only NPK fertilisers). The maintenance of carbon concentration within soil under conventional tillage and in native grassland was due to an enhanced incorporation of new organic matter from the coarse fraction of particulate organic matter to macro-aggregates and in treatment with ploughed crop residue together with NPK fertilisers, there was besides of this caused by the reduction of carbon mineralisation from the fine fraction. Soil management practices have a significant effect on the re-distribution of soil organic matter in water-stable aggregates. In conventional and minimal tillage, very important sources of carbon sequestration are agronomical favourable size fractions of water-stable macro-aggregates and in native grassland, as well as in all fertiliser treatments, the most important source of carbon sequestration is water-stable micro-aggregates.