Soil respiration in young and old oriental spruce stands and in adjacent grasslands in Artvin, Turkey

Abstract

Soil respiration is a good indicator of soil quality. In this study, the influence of species type and sampling time on soil respiration in young and old oriental spruce (Picea orientalis (L.) Link.) stands without understory and with a Rhododendron ponticum L. understory and in adjacent grasslands were investigated in Genya Mountain, Artvin, Turkey. Soil respiration was measured approximately monthly from May to October using the soda-lime technique. Mean daily soil respiration across all sites ranged from 0.26 to 2.66 g C m-2 d-1. There were significant differences between grasslands and old forest sites, but no significant differences between young forest sites and grasslands. Seasonal changes in soil respiration were strongly related to temperature changes. Over all sites, soil temperature and soil moisture together accounted for 75% of the seasonal variability in soil respiration. Mean soil respiration rates correlated strongly with fine root (<2 mm) biomass (R = 0.91, P < 0.001), surface (0-15 cm ) soil sand content (R = 0.71, P < 0.05), surface soil silt content (R = -0.69, P < 0.05), and subsurface (15-35 cm) soil pH (R = 0.60, P < 0.05). Overall, grasslands had significantly higher soil respiration rates than did adjacent old forests, indicating greater biological activity within the grasslands.

Toprak solunumu toprak kalitesinin nemli g stergelerinden bir tanesidir. Bu alYßmada, Artvin-Genya DaÛY mevkisindeki gen ve yaßlY doÛu ladini (ormang l diri rt s olan ve olmayan) ormanlarYnda ve bitißiÛindeki ayYrlYklarda, bitki t r ve rnekleme zamanYnYn toprak solunumu zerindeki etkileri belirlenmeye alYßYlmYßtYr. Toprak solunumu MayYs ayYndan Ekim ayYna kadar sodakire y ntemi yardYmYyla belirlenmißtir. Ortalama toprak solunumu 0,26-2,66 gr C m-2 g n-1 olarak deÛißmißtir. YaßlY ladin ormanY ile ayYrlYk arasYndaki toprak solunumu farkY istatistiki olarak anlamlY iken, gen doÛu ladini ormanY ile ayYrlYk arasYnda istatistiki anlamda nemli fark bulunamamYßtYr. Toprak solunumundaki mevsimsel deÛißimler toprak sYcaklYÛYndaki mevsimsel deÛißimlere paralel olarak ger ekleßmißtir. Toprak sYcaklYÛY ve toprak nemi, toprak solunumundaki varyasyonun %75Õini a YklamaktadYr. Ortalama toprak solunumu; ince k k k tlesi ile (<2 mm) (R = 0.91, P < 0.001), st topraÛYn (0-15 cm) kum oranY ile (R = 0.71, P < 0.05), st topraÛYn toz oranY ile (R = -0.69, P < 0.05), ve y zeyaltY topraÛYn (15-35 cm) pHÕsY ile (R = 0.60, P < 0.05) anlamlY olarak deÛißmektedir. Sonu olarak, ayYrlYk alanlar, yaßlY orman alanlarYna kYyasla daha fazla toprak solunumuna sahiptirler, bu da ayYrlYk alanlarda daha y ksek bir biyolojik aktivitenin olduÛunu g stermektedir.