不同覆盖栽培年限雷竹林生物量分配格局研究

A Study on Biomass Allocation Pattern of Phyllostachys praecox in Different Mulching Cultivation Periods

对不同覆盖栽培年限雷竹林生物量分配格局进行了研究,结果发现：随覆盖年限增加,新竹留养困难,歇园期间新竹留养不规律,导致竹林年龄结构不稳定,表现出1年、4年生竹子生物量下降,2年、3年生竹子生物量先升高后下降的总趋势,进而影响竹林年龄结构的人工可控性。竹林生物量在覆盖3年时有所升高,竹叶生物量的累积,应该是竹林仍能保持较高生产力的关键因素。竹叶生物量在竹林覆盖6年后开始有较大差异,到第12年已经跟覆盖0年、3年竹林达到显著差异水平,竹叶生物量的衰减成为长期覆盖竹林生产力衰退的重要限制因子。竹林覆盖到第3年,地下竹鞭根生物量才达到或接近饱和状态,说明竹林覆盖后虽然竹鞭有所上浮,但仍然有能力实现空间拓殖;继续覆盖,竹鞭上浮增大,生存空间缩小,竹鞭的萌发与生长受到限制,生物量逐渐衰减。竹鞭根是土壤养分主要吸收和运输器官,其生物量的衰减,势必会减弱竹林系统水分代谢及矿质营养等能力,进而影响竹林生长。研究认为,建立稳定的竹林年龄结构,提高留养新竹子质量,及时翻土深埋鞭,并结合可行的退化土壤生态修复技术,才能有效防止竹林生物量衰减,实现竹林可持续经营。

The biomass allocation patterns of Phyllostachys praecox in different mulching cultivation peri-ods were studied.The results showed that following the increase of mulching cultivation periods,the keeping of new bamboo became difficult,and with the irregular keeping of new bamboo in the paused mulching cultivation period,the age structure of bamboo forest became unstable,which exhibited an general trend that the biomass of one year old and four years old bamboo decreased,two years old and three years old bamboo firstly increased and then decreased,which further influenced the management controllability of bamboo age structure.Bamboo biomass increased in the 3-year mulched forest,the accumulation of bamboo leaf biomass might be the key factor for the high productivity of bamboo forest .Bamboo leaf biomass had greater variation after mulching for 6 years,in the 12-year mulched bamboo forest,there were significant differences compared with the 0-year and 3-year mulched forests,the attenuation of bamboo leaf biomass became an important limiting factor to the de-clining of bamboo forest productivity.After mulching for 3-year,the biomass of bamboo rhizome just reached the saturation state.This showed that,although the bamboo rhizome floated upward after mulching cultivation,it could still had the ability to occupy soil space.If mulching cultivation continued,bamboo rhizome floated up-ward constantly,with living space reduced,the germination and growth of bamboo rhizome were limited,and then the biomass decreased gradually.Bamboo rhizome was the main organ for absorption and transportation of soil nutrient,the attenuation of its biomass would certainly weaken the abilities of water metabolism and mineral nutrition of bamboo forest system,which further influenced the growth of bamboo forest.It is concluded that,a stable bamboo age structure,improved quality of new bamboo,deep soil and timely burial of bamboo rhizome, combined with the practical technology of ecological restoration of degraded soil might be able to prevent the attenuation of bamboo biomass effectively and then realize the sustainable management of bamboo forest.