Leaf litter Decomposition and Nutrient Dynamics of Persian Oak (Quercus brantii Lindl.) in the Northern Zagros Forests (Case Study: Chahar Zabar forests of Kermanshah)

Abstract

The return of nutrients through leaf litter is one of the most important ways of nutrient cycling and soil fertility conservation in forest ecosystems. The dynamics of nutrients and litter decomposition in the forest have great influence on the availability of soil nutrients.The present study was conducted with the aim of evaluating the nutrient dynamics and leaf litter decomposition in Persian oak (Quercus brantii Lindl.) leaf litter using litterbag method for 360 days in Chahar Zabar forests of Kermanshah province. In this study, litterbags (30×20 Cm and 2 mm mesh) were sampled with five replicates at intervals of 60, 120, 180, 240 and 360 days and the following factors were measured: decomposition rates, chemical components of leaf litters such as nitrogen, carbon, phosphorus, potassium, calcium, magnesium and AUR (Klason lignin). The results showed that in the first year, the mass loss of leaf litter was 45.9%. The nitrogen concentration was 12.22 mg.g-1 which indicates that Iranian oak is a tree with moderate soil modification. The concentration of nutrients was Ca (48.58 ± 0.37 mg.g-1) > N (25.16 ± 0.93 mg.g-1) > P (11.76 ± 0.36 mg.g-1) > Mg (2.73 ± 0.15 mg.g-1) > K (2.55 ± 0.27 mg.g-1). The results of nitrogen release and degradation of lignin showed that nitrogen release had a negative trend up to 180 days and then it was positive until the end of the period. Based on the stepwise regression the C/P and N were the only variables entered into the model which explained 85.8% of mass loss var­iation. In general, the results of this study showed that Iranian oak modified the soil nitrogen intermediately and has no high potential for humus production.

Keywords

• lignin
• mass loss
• mineralization
• nitrogen