Relationships between Cellulose Decomposition and Soil Environmental Factors in Three Coniferous Plantations

This study was carried out to determine the relationships between cellulose decomposition and soil environmental factors in larch (Larix leptolepis) and pine (red pine: Pinus densiflora; rigitaeda pine: P. rigida ${\times}$ P. taeda) species planted in the same year (1963). The variation of cellulose mass loss with soil temperature, soil pH, soil $CO_2$ efflux rates, and soil water content was measured monthly for 4 months (July, August, September and October 2006) from three coniferous plantations. Mean mass loss rates during the study period were generally more rapid in rigitaeda pine (6.5 $mg\;g^{-1}\;day^{-1}$) than in red pine (6.2 $mg\;g^{-1}\;day^{-1}$) or larch (6.1 $mg\;g^{-1}\;day^{-1}$) plantations, although the mass loss rates were not significantly different among three tree species (P > 0.05). Cellulose mass loss rates among three tree species were positively correlated with soil temperature (red pine: r = 0.77, P < 0.05; rigitaeda pine: r = 0.59, P < 0.05; larch: r = 0.48, P < 0.05) at the 20 cm soil depth, while the mass loss rates were negatively correlated with soil pH (red pine: r = -0.63, P < 0.05; rigitaeda pine: r = -0.47, P < 0.05; larch: r = -0.43, P < 0.05). There was a significant correlation between cellulose mass loss and soil $CO_2$ efflux rates except for regitaeda pine plantation, while no significant correlation (P > 0.05) between cellulose mass loss and soil water content in larch or rigitaeda pine. The results suggest that cellulose mass loss rates in soil layers depend on the different soil environmental factors caused by tree species.

3수종의 침엽수조림지내 셀룰로오스 분해와 토양 환경요인과의 관계

본 연구는 1963년도에 식재된 낙엽송, 소나무, 리기테다소나무 조림지를 대상으로 셀룰로오스 분해와 토양 환경인자 사이의 관계를 구명하기 위해 수행하였다. 셀룰로오스 분해에 영향을 미칠 수 있는 토양온도, 토양 수분함량, 토양 pH, 토양 이산화탄소 방출량을 2006년 7월부터 10월까지 4개월 동안 측정하였다. 셀룰로오스 분해율은 리기테다소나무($6.5mg\;g^{-1}\;day^{-1}$), 소나무($6.2mg\;g^{-1}\;day^{-1}$), 낙엽송($6.1mg\;g^{-1}\;day^{-1}$) 순이었으나 수종간 유의적인 차이는 없었다(P > 0.05). 셀룰로오스 분해율은 20cm 깊이의 토양 온도와 양의 상관(소나무: r = 0.77, P < 0.05; 리기테다소나무: r = 0.59, P < 0.05; 낙엽송: r = 0.48, P < 0.05)을 보였으나, 토양 pH와는 음의 상관(소나무: r = -0.63, P < 0.05; 리기테다소나무: r = -0.47, P < 0.05; 낙엽송: r = -0.43, P < 0.05)이 있었다. 토양이산화탄소방출량과 셀룰로오스 분해율은 소나무(r = 0.46, P < 0.05), 낙엽송(r = 0.37, P < 0.05), 토양 수분함량과 셀룰로오스 분해율은 소나무(r = 0.53, P < 0.05)와 유의적인 양의 상관(P < 0.05)이 있었다. 본 연구 결과에 따르면 셀룰로오스 분해는 각기 다른 침엽 수종으로부터 발생하는 토양 환경요인에 의해 영향을 받는 것으로 나타났다.