The aim of this study was to evaluate the influence of conventional and reduced tillage and fertilization on seasonal dynamics of basal respiration, soil organic matter and total content of nitrogen in topsoil layer by growing of common pea. The results refer to 2001-2003 years. The experimental site belongs to warm and moderate arid climatic region in the south-west of Slovakia. Common pea was growing in crop rotation: clover (Trifolium pratense L.) - winter wheat (Triticum aestivum L) - common pea (Pisum sativum L.) - maize (Zea mays L.) - spring barley (Hordeum vulgare L.) under different tillage and residue management practices. Three fertilization management practices as follows: 0-zero level without fertilization, F- mineral fertilizer calculated to the designed yield level, PR - incorporation above-ground plant material with mineral fertilizer for the balance equilibrium level. Mouldboard ploughing (0.2-0.22m) and disking (0.10-0.12m) was used. The soil samples were collected from the 0.075m topsoil layer three times (spring, summer and autumn samples). No significant differences of soil basal respiration between conventional (22.7 mg/1000g/day) and reduce tillage (23.4 mg/1000g/day) in topsoil layer has been noted. The average content of C ox was in interval 1.04%-1.16% without significant influence of tillage treatments. The significant changes of C: N ratio were influenced predominantly by variability of N t content. The high level of basal respiration and flux of CO 2 from unfertilized zero treatments and treatments with mineral fertilization (23.4 - 22.07 mg/1000g/day) are serious threat for the soil organic matter pool from long term perspective.

soil respiration; soil organic carbon; total nitrogen; crop sequences; common pea

Presentation: oral