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采用钻土芯与内生长相结合的研究方法,将马尾松占其混交林的组成比例分成5种类型(0～20%、21%～40%、41%～60%、61%～80%和81%～100%),设置15块20 m×20 m的标准样地,系统比较了不同比例马尾松混交林(马尾松占林分胸高断面积的比例)细根生物量的分布状况、细根生长量及季节动态变化。结果表明:(1)马尾松不同的混交比例对细根生物量有较大影响,不同混交比例林分的细根生物量的大小依次为,马尾松混交比例41%～60%﹥0～20%﹥21%～40%﹥81%～100%﹥61%～80%。(2)5种比例混交林分的细根生物量垂直分布规律均很明显,随土层增加细根生物量趋于减少,且大部分细根集中于土壤表层0～10 cm的范围内。这与该地区的土层较浅以及树种根系的分布特性(深根、浅根树种)密切相关。(3)5种马尾松混交林细根生物量季节动态均呈单峰变化,均在6、7月份达到峰值,在1月份达到最低值,41%～60%林分年生物量净增值比其他4种混交林分要高。(4)5种混交林分的细根年生长量随季节变化明显,最大值出现在6～8月份,最小值出现在12～3月份。各个混交林分细根年生长量大小依次为41%～60%﹥61%～80%﹥21%～40%﹥81%～100%﹥0～20%。
The proportion of Pinus massoniana in the mixed forest was divided into five types (0-20%, 21% -40%, 41% -60%, 61% -80% And 81% ~ 100% respectively). Fifteen standard plots of 20 m × 20 m were set up. The distribution of fine root biomass of Pinus massoniana mixed forest (Masson pine mass fraction) Fine root growth and seasonal dynamics. The results showed that: (1) Pinus massoniana different mixed proportion had a greater impact on the fine root biomass, the order of the fine root biomass of the mixed forest was 41% ~ 60%> 0 ~ 20 %> 21% ~ 40%> 81% ~ 100%> 61% ~ 80%. (2) The vertical distribution of fine root biomass of the five mixed forest stands was obvious. The fine root biomass tended to decrease with the increase of soil layers, and most of the fine roots concentrated in the range of 0-10 cm soil surface. This is closely related to the shallow soil layer in the region and the distribution characteristics of tree root system (deep root and shallow root tree species). (3) The fine root biomass of five Pinus massoniana plantations showed a single peak change in seasonal dynamics, both reaching the peak value in June and July and reaching the lowest value in January. The net annual net biomass value of 41 ~ 60% Mixed forest is higher. (4) The annual root growth rate of five kinds of mixed forest varied significantly with the seasons. The maximum appeared in June to August and the minimum appeared in 12 to March. The growth rate of fine roots in mixed forest was 41% ~ 60%> 61% ~ 80%> 21% ~ 40%> 81% ~ 100%> 0 ~ 20%.