【作者】 张洪霞；

【导师】 谭周进； 肖和艾；

【作者基本信息】 湖南农业大学 ， 微生物学， 2011， 硕士

【摘要】 我国南方红壤由于富含高岭石和铁锰氧化物等对磷有极强的专性吸附力的可变电荷矿物,以致土壤磷素有效性和磷肥作物利用率很低。土壤微生物是土壤营养元素(C、N、P、S等)转化和循环过程中的主要驱动力,探讨红壤土壤磷素转化主要功能微生物种群及其磷素转化和活化机理,对深入探讨促进红壤土壤磷素微生物转化和提高土壤磷素作物有效性具有重要的理论意义。本研究选择位于湖南桃源的红壤旱地和稻田田间定位试验土壤,在室内模拟培养条件下,研究了添加稻草以及细菌抑制剂(四环素和链霉素硫酸盐)或真菌抑制剂(放线菌酮)的旱地和淹水稻田土壤细菌和真菌的动态变化,探讨了土壤真菌和细菌对红壤不同利用类型土壤磷的固持效果,及其在土壤磷素转化中的作用,旨在阐明红壤旱地和淹水稻田土壤磷素转化的主要功能微生物群落及其对磷素有效性的作用机理。主要研究结果如下：(1)45 d培养试验结果表明,旱地土壤在培养的6d～45d期间,旱地土壤中添加稻草处理细菌和真菌数量比对照分别增加271.4%～518.8%和2900%～3608%,添加稻草+真菌抑制剂和添加稻草+细菌抑制剂处理比添加稻草处理土壤细菌数量分别增加34.1%～81.4%和下降14.3%～43.5%。添加稻草+细菌抑制剂处理土壤真菌增加17.1%～37.6%。淹水稻田土壤在培养的6d～45 d期间,添加稻草处理土壤细菌数量比对照处理增加115.3%～362.2%,而真菌数量下降5.8%～27.8%；添加稻草+细菌抑制剂处理土壤细菌数量比添加稻草处理下降39.0%～76.2%。(2)45 d培养试验结果表明,在0～45 d培养期间,添加稻草能使红壤旱地土壤微生物量碳和磷分别增加187.5%～193.1%和135.8%～148.7%,土壤速效磷增加27.5%～32.9%。施稻草能明显增加淹水稻田土壤微生物量碳含量,而微生物磷含量在培养过程中变化较大,但能增加淹水稻田土壤速效磷16.0%～21.2%。(3)45 d培养试验结束时(第45大),添加稻草的旱地土壤Fe-P和AI-P含量及固定态无机磷总量均显著增加,活性有机磷(LOP)、中活性有机磷(MLOP)、中度稳定性有机磷(MSOP)含量和有机磷总量也显著增加。添加稻草的稻田土壤Fe-P含量显著增加,Ca-P含量显著降低,土壤LOP含量和有机磷总量显著增加。因此,添加稻草能有效提高红壤旱地和稻田磷素的作物有效性。(4)培养试验结果表明,真菌和细菌均参与红壤旱地和稻田土壤磷素的固持过程,但旱地中可能真菌占主要作用,而淹水稻田中起作用的可能主要是细菌。更多还原

【Abstract】 Most of the phosphorus (P) in the red soils were usually associated with kaolinite, the oxides and hydrous oxides of iron (Fe) and aluminum (Al), so that the validity of soil phosphorus and the utilizing efficiency of phosphate fertilizer are very low. Soil microorganisms play an important role in the transformation of soil organic matter and soil nutrients (such as C, N, P, S, ect.). Researches on the mechanisms of soil phosphorus transformation and the functional microorganisms which involving in the soil phosphorus transformation can provide a theory reference for the effective usage and management of phosphorus in red soils. To know better the mechanisms in which organic amendment induced the microbial transformation of P in upland and paddy red soils, responses of culturable microbial diversity and changes in the microbial biomass C (MB-C) and P (MB-P), Olsen-P, adsorbed inorganic and organic P fractions were investigated using a series of long-term field trials in Hunan, China. The main results were summarized as follows:i)The data obtained from a 45-day incubation experiment showed that, compared with the treatment of control, the amount of culturable bacteria and fungi in the soil amended with rice straw were increased by 271.4%～518.8% and 2900%～3608% respectively, during the incubation period of upland soil, the treatment of both rice straw and fungal inhibitor (actidione) increased the amount of culturable bacteria by 34.1%～81.4% compared to the rice straw. In the treatments of rice straw and bacterial inhibitors (tetracycline and streptomycin sulphate), the amount of culturable bacteria decreased by 14.3%～43.48% compared to the rice straw, however, the amount of culturable fungi increased by17.1%～37.6%. During the incubation period of the flooded paddy soil, the amount of culturable bacteria increased by 115.3%～362.2% in the treatment of rice straw application, whereas the amount of culturable fungi decreased by 5.8%～27.8%, compared to the control (without rice straw amendment). The amount of culturable bacteria decreased by 39.0%～76.2% in the treatment of rice straw and bacterial inhibitors compared to the treatment with rice straw only.ii) Throughout the 45-day incubation period, the addition of rice straw significantly increased the amounts of MB-C and MB-P by 187.5%～193.1% and 135.8%～148.7%, respectively, in the upland soil, and increased the amounts of Olsen-P by 27.5%～32.9%. Whereas in paddy soil, the addition of rice straw increased the amounts of MB-C, and MB-P often changed in the incubation period, but also increased the amounts of Olsen-P by 16.0%～21.2%.iii) At the end of 45-day incubation period, the treatment of rice straw increased the amounts of Fe- and Al-bound P and total inorganophosphorus significantly in upland soil, and increased the amounts of LOP, MLOP, MSOP and total organophosphorus. The treatment of rice straw increased the amounts of Fe-bound P, LOP and total organo- phosphorus in paddy soil, and decreased the mount of Ca-bound P.iv) Moreover, both of the fungal and bacterial groups taken part in the microbial transformation of P in upland and paddy red soils, but the fungal group made a relatively larger contribution in upland soil, and in paddy soil the role may be played by the bacteria..更多还原