Long term field study (1996-2003) was conducted at the experimental site of Slovak University of Agriculture in Nitra in south-western Slovakia, to investigate the effects of different soil tillage practices and residue management on soil carbon sequestration under peas for grain growing after cereal forecrops. The average annual/growing season rainfall is 561/327 mm. The mean annual/growing season temperature is 9.7°C/16.2°C. The soil type is Orthic Luvisol with a loamy texture and a pH of 5.7. The experimental design was a split-plot with four replicates. The tillage was the main plot factor; the fertilization was the subplot factor. The subplots were 3 m wide by 10 m long and plots were subjected to primary soil tillage treatments as follows: mouldboard ploughing (CT) to a depth of 0.22 m (conventional tillage), twice shallow loosening (R) to a depth of 0.1 m (reduced tillage). Three fertilization treatments as follows: 0–without organic and inorganic fertilization, PH–mineral fertilizers calculated to the 3 t yield level, PZ–incorporation of all above-ground plant material supplemented with mineral fertilizer to the balance equilibrium level. Common pea (Pisum sativum L.) was growing after cereal forecrop (spring barley, since 2001 – winter wheat).The soil samples were collected from the 0.25 m. Soil bulk density for calculation of C sequestration was determinates in two layers. Temporal change was evaluated as absolute and net change. Absolute change in stored C from first year of field trial was strongly decline from 36.6 t ha-1 (1994) to average level 32 ha-1 ha (1996-2003). Net change of soil organic matter between tillage treatments revealed significant differences. The reduced tillage creates better soil condition for soil carbon accumulation (32.6 t ha-1) with comparison to mouldboard ploughing (31.4 t ha-1) in 0.2 soil layer. The fertilization treatments sequestered more carboneum with comparison to control treatment. Differences between the samples with application of mineral fertilizers (PH) or organic and mineral fertilizers (PZ) are associated with the decomposition of common peas residues or great amount of biomass production.

carbon sequestration; peas; residue management; tillage

Presentation: oral