毛竹林细根生长的趋富特化及对养分限制的响应

The “specialization for abundance” and response of nutrition limitation of fine root growth of Phyllostachys heterocycle cv.pubescens

为探讨毛竹林细根生长的趋富特化现象及对养分限制的响应,采用内生长土芯法在毛竹林地设置5种养分处理(NPK、NP、PK、NK、CK),定期收集根系样品,分成活细根(0~1mm,1~2mm,2~5mm)和死细根(0~5mm)。通过对不同养分处理下细根(0~5mm)生物量差异的研究,揭示其对缺素处理的响应及季节动态变化规律,为优化毛竹林科学施肥提供理论依据。结果表明:4种添加养分处理(NPK、NP、PK、NK)的全年平均细根生物量在各径级均显著高于CK处理(P<0.05),表现了细根生长的“趋富特化”现象。不同养分限制条件下细根生长的趋富特化特征存在差异,养分限制作用表现为P>N>K,NPK处理显著高于NK和PK处理(P<0.05),与NP处理之间差异不显著(P>0.05)。毛竹林全年细根生长表现为6月和10月生长高峰的双峰型,在高峰期细根生长所表现出的趋富特化特征更为明显。

In order to explore the phenomenon of enrichment of fine root growth and its response to nutrient limitation in Phyllostachys heterocycla cv. pubescens forest, five kinds of nutrient treatments (NPK, NP, PK, NK, CK) were set up in Phyllostachys heterocycla cv.pubescens with inner growth soil core method. Root samples were collected regularly, and the fine roots were divided into 0-1 mm, 1-2 mm, 2-5 mm and dead fine roots were divided into 0-5 mm, The difference in biomass between fine roots (0-5 mm) treated with different nutrients , reveal its response to the treatment of deficiency and seasonal dynamics, to provide theoretical basis for optimizing scientific fertilization of Phyllostachys heterocycla cv.pubescens forest. The results showed that the annual average fine root biomass of the four nutrient treatments was significantly higher than that of the CK treatment (P < 0.05), which showed the phenomenon of “specialization for abundance” of fine root growth. The effects of nutrient restriction on fine root growth were significantly higher than that of NK and competitive treatment (P < 0.05), but there was no significant difference between NPK and NP treatment (P > 0.05). The growth of fine roots in Phyllostachys pubescens forest showed two peaks in June and October, especially in the peak period of fine root growth.