Characteristics of organic carbon content of leaf-litter-soil system in Pinus sylvestris var. mongolica plantations

ObjectiveOrganic carbon plays an important role in the ecological system material cycle and global carbon cycle. Pinus sylvestris var. mongolica is one of the most important afforestation tree species for farmland protection and windbreak shelterbelts in northern China. By analyzing the leaf, litter, and soil organic carbon content of P. sylvestris var. mongolica plantations in different bioclimatic zones, the distribution characteristics of organic carbon in leaf-litter-soil system of P. sylvestris var. mongolica plantations were explored.

MethodThree age groups of P. sylvestris var. mongolica plantations (middle-aged, near-mature, and mature) in the Hulunbuir, Horqin, and Mu Us Sandy Land were studied. Based on the determination of organic carbon content in leaf, litter, and soil, the difference of organic carbon content of leaf, litter, and soil in different regions with different ages was analyzed by one-way ANOVA and LSD multiple comparison method. The significant influence of climate zone and forest age on organic carbon content was analyzed by two-way ANOVA method. Person correlation was used to analyze the correlation between leaf, litter, and soil organic carbon content in different bioclimatic zones.

Result(1) The organic carbon contents in leaf, litter, and soil at the different age groups were in the range of 604.06-675.69, 343.02-538.51, and 0.72-11.73 g/kg, respectively. (2) With the increase of forest age, the organic carbon contents of leaf, litter, and soil increased firstly and then decreased in each sandy land (near-mature forest > middle-aged forest > mature forest). (3) The climate zone and forest age had no significant effect on the content of organic carbon in the leaf of P. sylvestris var. mongolica, while had significant effect on the litter and soil organic carbon at P < 0.05 level. Also, there were significant (P < 0.05) or extremely significant (P < 0.01) positive correlations among the organic carbon contents of leaf, litter, and soil.

ConclusionThere is organic carbon transport and conversion in the leaf-litter-soil system of P. sylvestris var. mongolica. P. sylvestris var. mongolica adapts to environmental changes by adjusting its structure and function. In particular, it's worth mentioning that the leaf has a high environmental adaptability. The study is conductive to a better understanding of carbon cycling in P. sylvestris var. mongolica plantations, which also provide theoretical support for P. sylvestris var. mongolica plantation management.