喀斯特石山不同演替阶段檵木群落土壤温湿度变化

Variation of Soil Temperature and Moistureat Different Successional Stages of Loropetalum chinense Communities in Karst Hills of Guilin,China

研究桂林喀斯特石山不同演替阶段檵木群落土壤温湿度的变化是理解喀斯特石山檵木天然林演替规律的重要基础。在2017年3月至2018年2月期间,使用EM50传感器对灌木阶段、乔灌阶段和小乔林阶段等不同演替阶段的檵木群落不同土层(0、5和10 cm)温湿度变化进行监测。结果表明:1)不同演替阶段檵木群落各土层土壤温度在不同季节的日变化曲线均为正弦曲线。除夏季土壤湿度日变化波动相对明显外,其余季节均较为平稳。2)不同演替阶段各土层土壤温度均在8月达到全年最高温,为(25.55±0.66)~(26.75±0.72)℃,最低温在1月,为(9.13±2.82)~(11.04±1.90)℃。不同演替阶段各土层土壤湿度在6—7月达到全年最大值(28.19%±1.99%~36.06%±3.86%),在10—11月达到全年最小值(10.97%±1.09%~18.26%±0.44%)。3)不同演替阶段檵木群落各土层土壤温度各月整体上随演替的进行均呈下降趋势。不同演替阶段土层0 cm处土壤湿度随演替的进行呈上升趋势,对于深层土壤而言,土壤湿度随演替的进行没有明显的规律性变化。综上,檵木群落内土壤环境随着演替的进行由最初的“高温低湿”逐渐向“低温高湿”的环境转变,这为喀斯特石山檵木群落自然演替发展与环境因子的协同作用规律提供理论依据。

Analyzsis of the variation of soil temperature and moisture at different successional stages of Loropetalum chinense communities in karst hills of Guilin is a key basis for the understanding of the successional laws of L.chinense natural forests in karst hills of Guilin.The soil temperature and moisture sensors EM50 were used to continuously monitor temperature and humidity in different soil layers(0,5 and 10 cm)of shrub stage,shrub to tree stage and small tree stage of L.chinense communities in karst hills of Guilin between March 2017 and February 2018.The variation of soil temperature and moisture at the three successional stages were analyzed.The study results indicated that,(1)The diurnal variation curve of soil temperature in different seasons showed the same sinusoidal curve in each soil layer at different successional stages of L.chinense communities.Except in summer,the diurnal variation of soil moisture was relatively stable.(2)The soil temperature of each soil layer reached the highest temperature in August(25.55±0.66—26.75±0.72℃)and the lowest temperature in January(9.13±2.82—11.04±1.90℃)at different successional stages,respectively.The soil moisture of each soil layer reached the maximum value from June to July(28.19%±1.99%—36.06%±3.86%)and minimum value from October to November(10.97%±1.09%—18.26%±0.44%).(3)The soil temperature of each soil layer decreased with succession in each month at different successional stages of L.chinense communities.And soil moisture of 0 cm layer increased with succession at different successional stages of L.chinense communities.In the deep soil layers,soil moisture didn’t show a obvious trend along the successional gradient of L.chinense communities.To sum up,the soil environment gradually recovered from high temperature and low humidity to low temperature and high humidity trend along the successional gradient of L.chinense communites.The results provide a theoretical basis for the synergy of natural succession development and environmental factors of L.chinense communities in karst hills of Guilin,China.