摘要
在黄土高原半干旱地区,植物种群生态的改善是植被建设与生态修复的关键。通过人工植被调查,比较了四种豆科牧草的种群生长的生态差异,初步探讨了牧草生产力与种群生态的可能耦合网络机制。结果表明:基于四种豆科牧草种群的土壤水分含量和垂直下降分布规律,发现沙打旺与苜蓿为高生产力型,红豆草与胡枝子为低生产力型,这可能与它们水分利用状况和豆科牧草本身的固氮或氮沉积的氮汇与源转化调节有关。苜蓿植株生物量表现较高,与其多年生庞大根系充分吸收土壤深层水分有关,反映了根冠生长与土壤条件的耦合是导致遗传特性响应差异的重要原因,因此调整植物根冠关系以增强植物的抗旱适应能力理论上是可行的。相关分析发现生产力、根系生物量、土壤环境(水分和层次)为网络耦联相关,特别是90-100cm的土壤空间水分与根冠比成正相关,这可能说明这个层次(根系的浅层集中分布区)为土壤水库与土壤干层相转变的阈值界面。因此从干旱胁迫条件下建立的适应性生存对策上考虑,苜蓿适宜在干旱立地推广应用,不仅具水土保持功效,而且植被生产力高,应为黄土高原生态恢复和生态建设的重要参考物种。
In semi-arid Loess Plateau of Northwestern China,the improvement of population ecology is critical for vegetation construction and ecological restoration related to sustainable development.In the present study,with artificial investigation of vegetation parameters,ecological difference for four leguminous forages population is compared and analyzed.Meanwhile,it also discusses possible coupling mechanism between herbage productivity and population ecology based on network relationship analysis.It is discovered that four materials show similar distribution law of soil water,declining vertically with soil depth,even with significant content difference of soil moisture.From the opinion of net primary productivity,two types are divided as high productivity in Medicago sativa and Astragalus adsurgens,low for Onobrychis viciaefolia and Lespedeza dahurica.The separation closely relates to water utilization property of interspecific specificity as well as nitrogen transition of N deposition and fixing.M.sativa displayed high aboveground biomass,which combines markedly with giant roots imbibing soil water even from deep layer.This reflects that the coincidence between canopy growth and soil circumstance will significantly lead to response of genetic difference to any stress like drought.Therefore,it is feasible to enhance drought resistance for adjusting root and canopy relationship from the theory view.With the relationship analysis,it is deduced that vegetation productivity,roots biomass and soil environment such as water and physical layer is correlated as a net system.In soil depth as 90-100 cm for roots distribution districts,it is observed that soil moisture show position relation to the ratio of root to canopy,which is assumed that it will be the interface about soil water storage and deficit.Based on the above description,M.sativa is adaptive to be popular in the loess Plateau from living strategy among four tested species.It results from its better benefit of soil and water conservation,but also with higher produc
出处
《水土保持研究》
CSCD
北大核心
2010年第1期167-173,共7页
Research of Soil and Water Conservation
基金
中科院"百人计划"择优支持项目(C24016200)
国家自然科学基金(30900186)
安徽高校省级自然科学研究项目(KJ2008B192):黄土高原土壤侵蚀与旱地农业国家重点实验室基金(10501-242)
安徽师范大学校科研专项(2009xzx15)
关键词
豆科牧草
种群生态
干旱胁迫
植被生产力
源库调节
生长对策
Leguminous forage
population ecology
drought press
vegetation productivity
Source-Sink Modulation
growth strategy
