滇东岩溶高原云南松水源林产水功能恢复机理研究

Restoring the water-production layers of the epikarst zone is the key to restore the water production function of water sources. Based on the hypothesis that an effective revegetation can help water sources form the function of water self-maintaining-and-adjusting and promote the reconstruction of the water-production layers of epikarst zones as well as the restoration of its water production function, the author of this program conducted simultaneous observations in sea-peak-karst-hill (peak cluster) lake basins in the east Yunnan plateau to how the successtion of Pinus yunnanensis influenced the water flow and the circulation of aquatic chemistry of the runoff generation of epikarst zones. According to the measurement of karst permeation pattern, the conversion between soil erosion and leakage and the varation of water nutrition abundance, the author analyzed the process and methods of how the succession of vegetation influenced the restoration of the water-production layers of epikarst zones, and according to the information of how water flow, stable isotope and the nutrition abundance of aquatic chemistry varied during the allocation, restoration and conversion of vegetation, soil layer and epikarst zones, the author analyzed the process and mechanism of how the succession of vegetation influenced the restoration of epikarst zones’ water-production functions. This study contributed to understanding the process and methods of how the succession of Pinus yunnanensis water-source forest in Yunnan influenced the restoration of the water-production layers of epikarst zones its water-production function in water sources, revealing the mechanism of recovering the water-production functions of water sources in the east of Yunnan karst plateau, and providing theoretic references and technical support for the pattern of effectively recovering Pinus yunnanensis in the east of Yunnan karst plateau.

表层岩溶带产水层的再发育是水源地产水功能恢复的关键。本项目基于“植被有效恢复促进水源地形成水分自养调节功能，促进表层带产水层的再发育及其产水功能的恢复”的研究假设，选择在滇东高原海峰溶丘（峰丛）湖盆区开展云南松群落恢复演替影响表层带产流的水分流量过程和水化学循环过程的同步观测实验。依据表层带溶蚀渗透格局、枯落物养分释放、土壤流失与漏失平衡转化过程的测量以及水分养分丰度变化信息，分析植被演替影响表层带产水层再发育的过程和方式；依据水分在植被、土壤层、表层带的分配、存储和转化过程中的流量、稳定同位素以及水化学丰度变化信息，分析植被演替影响表层带产水功能恢复的过程和机理。项目研究有助于弄清云南松水源林群落演替影响水源地表层带产水层再发育和产水功能恢复的过程和方式，揭示滇东岩溶高原水源地产水功能恢复机理，为滇东岩溶高原云南松有效恢复模式提供理论参考和技术支持。

针对云南松恢复演替与滇东岩溶高原表层带产水功能恢复的协同演变关系，运用典型样地观测以及稳定同位素示踪等研究方法，在海峰岩溶盆地石漠化坡地区开展了水分流量过程和水化学循环过程的同步观测实验。结果表明：（1）云南松各群落枯落物蓄积量、分解速率与养分释放、土壤SOC、TN、TP含量与其恢复过程表现出高度的一致性，均为元江栲栎原生林>云南松天然次生林>云南松人工混交林>云南松纯林>小铁仔灌丛；云南松群落土壤SOC积累较快，N素缺乏成为制约演替速率的主要因素；云南松次生林和混交林枯落物N素释放速率的提升与混交的乡土阔叶树种有关；云南松恢复有利于大粒径（>5mm、2-5mm）土壤团聚体的形成，而小粒径（0.25-0.5mm和＜0.25mm）土壤团聚体具有较强的养分固持能力。（2）坡面年产沙量显示：云南松纯林（50.67kg·hm-2）>小铁仔灌丛（49.26kg·hm-2）>云南松人工混交林（43.29kg·hm-2）>云南松次生林（38.46kg·hm-2）>元江栲栎林（31.67kg·hm-2）。土壤流失量明显大于溶蚀成土量（流域溶蚀成土速率33.49 t‧km-2a-1）；云南松次生林和混交林有助于提高表层土壤的抗侵蚀性，增加中层和深层土壤抗剪强度，减缓土壤流失/漏失效应更显著。（3）5种群落林冠截留率：元江栲栎林（24.84%）>云南松次生林（21.77%）>云南松人工混交林（20.80%）>云南松纯林（16.11%）>小铁仔灌丛（14.35%），枯落物层最大持水率介于261.02%-401.03%之间；年径流深和总径流深显示：小铁仔灌丛>云南松纯林>云南松人工混交林>云南松天然次生林>元江栲栎林，降雨量和60min最大雨强是影响径流系数的主要因素；土壤水文功能评价显示：元江栲栎原生林（1）＞云南松天然次生林（0.64）＞云南松人工混交林（0.61）＞云南松纯林（0.53）＞小铁仔石灰岩灌丛（0.31），表明云南松群落“水分自养调节功能”逐步形成。（4）深层土壤水及表层岩溶地下水是旱季云南松稳定的补给水源，云南松群落植物水分利用效率WUE高呈现水分利用竞争关系；叶片δ13C显示云南松群落植物WUE受叶片N、P养分的共同限制；云南松次生林和混交林植物N、P含量和WUE均优于云南松人工纯林。云南松天然次生林、云南松与典型乡土树种的混交林是海峰流域优选水源林目标群落。