不同母质发育的紫色土壤对水体初级生产力的贡献

Bottom soil have a pronounced effect on the primary productivity in the pond water. However, to date, a little information is available of different soils affecting the phytoplankton growth. In previously study, we have discovered that, there are significant differences in the natural succession of phytoplankton growth in different purple soil extracts, and population of pure-cultured Chlorella have different fluctuations when equal exogenous phosphorus added into the different purple soil extracts. In present research proposal, we will further investigate the impact of the different rock derived-purple parent soils on the primary productivity in water and discover its influencing mechanism. In order to explore the probable nutrition restrictive factors for algae growth, soil chemistry and water chemistry analysis techniques will be employed to measure the properties and mineral nutrients content of both the soils and the soil solutions. And then, to make clear the influencing mechanism of different purple parent soils on the primary production in the water, a simulation experiment will be carried out in the corresponding purple parent soils contained- ponds. The algae succession, the fluctuation of the primary production, and the changes of nutrients in water and sediment will be surveyed in the simulation experiment system. The present research can provide theoretical and technical support for the ecological control of water nutrition in purple soil ponds, and will contribute to establish a evaluation method of suitableness for fish farming regarding of purple soils. It has important theoretical and practical significance for the pond aquaculture in China.

池塘底质土壤对水体初级生产力有重要影响。我们研究发现，在不同的紫色土浸出液中，不仅浮游藻类自然演替特征明显不同，而且纯培养的小球藻等藻类在添加等量外源磷后的种群响应特征也有显著差异。因此，本课题就几种不同紫色母岩发育的池塘土壤对水体初级生产力的贡献及作用机制开展深入研究。首先，借助土壤农业化学和水环境化学分析技术，研究土壤及其浸出液的性质和重要养分元素含量与比例，并结合藻类的营养需求特性，探明不同紫色土池塘中藻类增长的营养限制因子；其次，通过室外模拟实验深入研究不同土壤淹水培养系统中的藻类群落演替动态、初级生产力变化及其与水体和底泥养分动态之间的关系，揭示不同紫色土对水体初级生产力的影响机制。本研究可为紫色土地区池塘的水体营养生态调控提供理论和技术支撑，有助于建立池塘土壤"宜渔性"评价的方法，对推动我国池塘养殖可持续健康发展具有重要的理论和实践意义。

不同母质发育的土壤，其质地、性质和矿质养分含量等有明显差异，对水体初级生产力(藻类增长)有决定性影响，进而影响水质、鱼产量乃至产品质量。本项目就不同紫色母岩发育的池塘土壤对水体初级生产力的贡献及作用机制，开展了全面深入研究，有关研究是现代水产养殖理论完善和技术进步的需要，具有重要的理论和实践价值。. 通过研究不同母质紫色土及其浸出液的性质和有效养分，尤其是磷素的形态与量比分析，并根据藻类营养需求特性，明确了所研究的不同紫色土“泥—水”系统中藻类萌发密度、生物量、种类数均与土壤有效磷含量等存在线性关系，“磷”是所有紫色土池塘初级生产力的首要营养限制因子；酸性紫色土中P、N和 Ca等容易成为初级生产力营养限制因子，碱性紫色土和中性紫色土营养供给较酸性紫色土好。研究结果能为紫色土池塘水体营养调控和水质改良提供有效方案。. 通过室内、室外模拟试验，研究了不同紫色土“泥-水”系统中的浮游藻类群落结构变化特征、底泥和水体性质与养分变化，初步揭示紫色土母质土壤的酸碱度、养分含量（尤其是P、N和Ca）差异是影响池塘水体初级生产力高低的重要因素，典型紫色土壤的“宜渔性”评估第一依据是土壤pH，其次考查P的养分含量与形态，再次考虑N、Ca以及土壤总养分含量，另外考虑微量元素的丰欠。