Comparison of decomposition rates of beech (Fagus orientalis Lipsky) and spruce (Picea orientalis (L.) Link) litter in pure and mixed stands of both species in Artvin, Turkey
Künye
Sarıyıldız, T., Tüfekçioğlu, A., & Küçük, M. (2005). Comparison of decomposition rates of beech (Fagus orientalis Lipsky) and spruce (Picea orientalis (L.) Link) litter in pure and mixed stands of both species in Artvin, Turkey. Turkish Journal of Agriculture and Forestry, 29(6), 429-438.Özet
The decomposition of spruce, beech and mixed litters of spruce and beech was investigated over 3.5 years in beech, spruce and mixed (beech/spruce) stands using less than 1.5 mm mesh litter bags. Initially, carbon, nitrogen, lignin and cellulose concentrations, and C:N and lignin:N ratios were determined in beech and spruce litters. For all sampling intervals, mixed litters showed higher decay rates than individual beech and spruce litters in both pure stands and mixed stands. Spruce decomposed more rapidly than beech, and initial lignin concentration explained most of the variation in decomposition rates between beech and spruce. However, differences in decomposition rates between beech and spruce were most pronounced in the mixed stand, while they were intermediate in the beech stand and least pronounced in the spruce stand. This shows that adverse environmental conditions, mostly associated with a lower pH content of the soil under spruce stands, retard decomposition processes and individual litters appear to be more sensitive to this retardation than mixed litters. The results also indicate that abiotic and microbial factors in mixed stands could be better than those in pure stands of spruce and beech. Therefore, the establishment of mixed beech and spruce stands can counteract detrimental processes in decomposition associated with spruce monocultures. Bu çal›flmada, saf kay›n ve ladin meflçerelerinde ve kay›n-ladin kar›fl›k meflçerelerinde, kay›n yapraklar›n›n ve ladin ibrelerinin
kar›fl›k ve saf olarak yerlefltirildi¤i gözenekli naylon pofletlerde (20 X 20 cm geniflli¤inde ve 1.5 mm den küçük gözeneklere sahip
naylon pofletler) ayr›flma oranlar› 42 ay süresince araflt›r›lm›flt›r. Çal›flman›n bafllang›ç aflamas›nda, kay›n yapraklar›n›n ve ladin
ibrelerinin içerdi¤i karbon, azot, lignin ve selüloz miktarlar› ile C:N ve Lignin:N oranlar› belirlenmifltir. Örnekleme zamanlar›n›n
hepsinde, sadece kay›n yapra¤› ve ladin ibresi içeren pofletlerdeki ayr›flma, hem saf hemde kar›fl›k meflçereler alt›nda, kar›fl›k örnekler
içeren pofletlerden daha az olmufltur. Ladin ibreleri, kay›n yapraklar›ndan çok daha h›zl› ayr›flm›fl, bu iki türün bafllang›çta içerdi¤i
lignin miktar›n›n bu türlerin ayr›flma oranlar›n› etkileyen en önemli etken oldu¤u belirlenmifltir. Bununla beraber, ladin ve kay›n
aras›ndaki ayr›flma oranlar› fark›, kar›fl›k meflcerelerde en fazla, kay›n meflceresinde orta derecede, ladin meflceresinde ise en az
olarak tespit edilmifltir. Bu sonuç, ladin meflcereleri alt›ndaki olumsuz ortamlar›n (özellikle topraklar›n düflük pH de¤erlerinin) ibre
veya yapraklar›n tek bafllar›na olan ayr›flmas›n› önemli derecede yavafllatt›¤›n›, fakat ibre ve yapraklar›n kar›fl›m halinde olmalar›
durumunda, ladin meflcereleri alt›ndaki bu olumsuz ortamlardan daha az etkilendi¤ini göstermektedir. Ayr›ca çal›flman›n sonuçlar›,
kar›fl›k meflcerelerdeki abiyotik flartlar›n ve mikroorganizma faaliyetlerinin saf kay›n ve ladin meflcerelerinden daha iyi olabilece¤ini
düflündürmektedir. Bu nedenle, kay›n ve ladin kar›fl›k meflcerelerin tesisinin saf ladin meflcerelerindeki ölü örtü ayr›flmas› üzerindeki
yavafllat›c› etkileri gidermede rol oynayabilece¤i sonucuna var›lm›flt›r.