生态茶园植物残体在不同空间的分解动态

Decomposition dynamics of plant residues in ecological tea plantations across different spatial scales

【目的】探索不同植物在不同空间的自然分解变化过程,为茶园的物质养分循环及维持土壤肥力提供理论依据。【方法】采用分解袋法分析茶(Camellia sinensis)修剪物、光皮桦(Betula luminifera)、猴樟(Cinnamomum bodinieri)、杉木(Cunninghamialanceolata)和马尾松(Pinusmassoniana)的植物残体在土壤、林冠和地表的分解特征、时间动态及不同阶段分解速率差异。【结果】植物残体自然分解过程中总体呈快—慢的变化趋势,不同空间的残体质量损失率为土壤>地表>林冠,具体为茶修剪物、光皮桦和猴樟的残体质量损失率随高度升高逐渐减少,杉木和马尾松的残体质量损失率随高度升高先增加后减少。多因素方差分析表明,空间、时间、树种及三者间交互作用极显著影响植物残体干重剩余率(P<0.01),影响最大为时间,其次为空间和树种,最小为三者交互作用。利用Olson指数衰减模型估计各树种分解系数发现,总体上林冠分解速率低于地表和土壤,针叶树种植物残体分解速率小于阔叶树种。不同树种分解速率存在差异,地表和土壤中前期的分解速率明显大于后期,林冠和土壤的年分解速率排序依次为茶修剪物>光皮桦>猴樟>马尾松>杉木,而地表的年分解速率种间排序依次为茶修剪物>光皮桦>猴樟>杉木>马尾松,且茶修剪物、光皮桦和猴樟的年分解速率与空间具有显著线性正相关关系(P<0.05),杉木和马尾松则无显著相关(P>0.05)。【结论】地表和土壤相较林冠能提高植物残体利用效率,适当清除林冠累积的植物残体,并将其置于土壤和地表环境更利于其降解。

【Objective】To explore the natural decomposition change process of different plants in different spaces and provide a theoretical basis for the material nutrient cycle and maintenance of soil fertility in tea plantations.【Method】The decomposition bag method was used to analyze decomposition characteristics,temporal dynamics,and differences in de-composition rates at different stages of plant residue decomposition in soil,forest canopy,and surface of tea(Camellia si-nensis)prunings,light-barked birch(Betula luminifera),monkey camphor(Cinnamomum bodinieri),cedar(Cunning-hamia lanceolata),and horsetail pine(Pinus massoniana).【Result】The overall trend of natural decomposition of plant residues was fast-slow,and the rate of residue mass loss in different spaces was soil>surface>crown.Specifically,the rate of weight loss of tea prunings,light-barked birch,and monkey camphor gradually decreased with increase of height,and that of cedar and horsetail pine first increased and then decreased with increase of height.Multi-factor analysis of variance showed that space,time,tree species,and three-way interaction extremely significantly affected the dry weight residual rate of plant residues(P<0.01),with the most significant effect being time,followed by space,tree species,and the smallest being three-way interaction.Using Olson’s exponential decay model to estimate the decomposition coefficients of each tree species,it was found that the overall decomposition rate of the forest canopy was lower than that of the surface and soil,and the decomposition rate of plant residues of coniferous species was lower than that of broadleaf species.There were differences in decomposition rates among different tree species,and the decomposition rate in the early stage was sig-nificantly greater than that in the late stage in the surface and soil.The annual decomposition rate of the forest canopy and soil was ranked as tea prunings>light-bark birch>monkey camphor>horsetail pine>cedar.At the same time,that of the sur-face was the inter-species ranking of tea prunings>light-bark birch>monkey camphor>cedar>horsetail pine.And the an-nual decomposition rates of tea prunings,light-bark birch,monkey camphor had a significant linear positive correlation with the space(P<0.05),the relationship between cedar and horsetail pine was insignificant(P>0.05).【Conclusion】The surface and soil can improve the efficiency of plant residue utilization compared to the forest canopy,and appropriate re-moval of plant residues accumulated in the forest canopy and placing them in the soil and surface environments is more conducive to their degradation.