博斯腾湖沉积物氨氧化细菌的筛选与鉴定

为了解干旱区淡水湖泊沉积物微生物在氨氧化中的功能,利用铵盐培养基对博斯腾湖不同深度沉积物进行驯化培养,结合水环境因子分析混合菌株产亚硝酸盐能力,从中分离纯化氨氧化细菌并对其氨转化能力进行试验。结果表明,6个采样位点12个样品中,11号位点深层沉积物(20～40 cm)混合菌株能有效利用铵盐产生亚硝酸盐,且连续6 d稳定维持其质量浓度高达20 mg/L以上。进而,从该混合菌液中分离得到30株单菌,其中有2株呈现出明显的氨氧化细菌特性。通过16S rRNA基因序列比对及形态学分析分别鉴定其为弯曲芽孢杆菌(Bacillus flexus)和赤红球菌(Rhodococcus ruber)。     

MS微滤材料在活性炭废水治理中的应用与研究

详尽论述了以ＭＳ微滤材料为核心的过滤器代替沉淀地治理活性炭废水的应用与实效，利用过滤法回收活性炭，活性炭回收率高达９９％，同时实现出水回用；社会和经济效益大，从根本上改变了劳动条件。     

电容式水流泥沙含量传感器温度补偿技术的研究

采用自行研制的电容传感器测量了水流中泥沙含量与传感器输出电压，研究了测量水流泥沙含量的温度补偿技术。结果表明，水流泥沙含量与传感器的输出电压呈线性关系，传感器的输出随温度的升高而逐渐增大；通过对温度的监测并由软件实现补偿的方法，可大大提高测量的精度；该方法能得到工作温度范围非标定条件下任一温度状态的输入－输出特性，可显著提高其温度稳定性。     

湖泊底泥氮营养释放特征研究

通过模拟培养，研究了底泥氮营养的释放及上覆水体中氮营养的浓度变化特征。结果表明，在扰动下，底泥向上覆水体明显地释放氮营养，而消亡的水华更可以激发底泥中有机氮的释放，底泥中有机氮的矿化释放与沉积到底泥表层的水华量密切相关。释放进入上覆水体中氮首先以铵氮存在，并快速向亚硝氮转化，此后才向硝氮转化。水中铵氮浓度高，存在时间长，是比较主要的氮形态。     

河岸带生态系统管理模型研究进展

（西南大学资源与环境学院，重庆数字农业重点实验室，重庆 400716）     

花岗岩地区坡耕地径流泥沙观测试验研究

本文总结分析了三年来对花岗岩地区坡耕地径流泥沙的观测试验资料, 得出以下结论: 1.荒坡地的泥沙流失量大于作物地; 2.作物地覆盖度低于30%以下则比荒坡地的泥沙流失量要大; 3.大于25°的坡耕地, 头两年产量虽然较好, 但第3年以后产量大幅度下降, 并造成大量的泥沙流失, 故种多年生植物为佳。 同时通过试验研究表明: 在花岗岩地区, 泥沙流失量多数来源于坡耕地。 因此搞好坡耕地的综合治理, 是防治水土流失提高单位面积产量的关键措施。     

Modelling of snowmelt erosion and sediment yield in a small low-mountain catchment in Germany

Temporal variability and spatial heterogeneity of surface runoff generation triggers the dynamics of source areas of sediment and sediment-associated nutrient transport. Reliable modelling of hydrological special situations i.e. snowmelt is of high importance for the quality of erosion and sediment yield modelling. Data from the research catchment Schäfertal demonstrate the individuality of snowmelt events in terms of runoff coefficient and delivery ratio. This 1.44 km² low mountain catchment is characterised by a high portion of arable land with a winter grain/winter rape crop rotation. The integrated winter erosion and nutrient load model (IWAN) considers these dynamic aspects by coupling a hydrological model with a sediment load model. Cell size of this raster-based approach is 10 × 10 m². Additionally, snowmelt rill erosion is simulated with a newly developed physically based model that is firstly applied on a catchment scale. A sensitivity analysis of this model system component demonstrates the plausibility of the model approach and the overall robustness of the model system IWAN. The results of the long-term hydrological modelling from 1991 to 2003 are reliable and form the basis for the simulation of six snowmelt events which were observed in the Schäfertal catchment. The estimated total runoff volumes for these events match the observations well. The modelled overland runoff coefficients vary from 0.001 to 0.72. The mean values of cell erosion, which were modelled with one set of parameters for all six events range from 0.0006 to 0.96 t ha^− 1. The total modelled erosion for the events with unfrozen soil and low amount of surface runoff is of a factor 50 below those with partly frozen soil. In addition to these distinctions, the major differences are caused by flow accumulation in shallow depressions in variable parts of the catchment. However, the validation of these results on the single event scale is restricted due to limited spatial data. Total simulated sediment yield at the catchment outlet was as high as 13.84 t which underestimates the observed values, with the exception of one event. Oversimplification of the modelled channel processes may be a reason. The temporal variability and spatial heterogeneity of the surface roughness parameter, which was identified to be sensitive, also causes uncertainty in the parameter estimation. Despite these findings, the model system IWAN was applied successfully on the catchment scale and the simulated results are reliable.     

聚丙烯酰胺增加土壤降雨入渗减少侵蚀的模拟试验研究Ⅱ.侵蚀

土壤侵蚀和雨水的流失是干旱、半干旱地区制约农业发展乃至生态环境良性循环的两个主要因素。聚丙烯酰胺 (PAM ,Polyacrylamide)对土壤的性质有着明显的改进作用 ,PAM具有良好的黏结力 ,能有效改良土壤的表层结构 ,提高土壤的稳定性 ,增加土壤的入渗率 ,减少土壤侵蚀。本文试图通过人工降雨模拟实验 ,获得不同的PAM的使用量及覆盖率与土壤侵蚀量在不同的雨强、不同的坡度条件下的关系。实验表明 ,经PAM处理后土壤的入渗性能和抗侵蚀的性能都有所提高 ,PAM能明显地黏结着土壤表面的颗粒 ,形成大的团聚体 ,阻碍土壤结皮的形成 ,减少土壤侵蚀。     

Multi-parameter fingerprinting of sediment deposition in a small gullied catchment in SE Australia

The determination of relative contributions of potential sediment sources is an important step in the development of management strategies to combat soil erosion. In a 1.2 km² gullied catchment in southeastern New South Wales, multi-parameter fingerprinting of sediment deposited in successive downstream pools has identified gully walls as the dominant sediment source when the grazed pasture surface was the only other potential source. The median fractional contributions remained relatively steady in the successive downstream pools, with the gully walls responsible for between 90% and 98% of the pool sediment. This result was achieved despite the ratio of the source areas varying considerably between successive nested subareas. Reliability bounds on the predictions, accounting for limited sampling of sources, were well constrained and varied between 5.4% and 13.8%. Downstream of an unsealed road crossing, sediment from the road source dominated the pool sediments such that contributions from the pasture surface and gully sources could not be determined.     

A simple approach to soil loss prediction: a revised Morgan–Morgan–Finney model

A revised version of the Morgan–Morgan–Finney model for prediction of annual soil loss by water is presented. Changes have been made to the way soil particle detachment by raindrop impact is simulated, which now takes account of plant canopy height and leaf drainage, and a component has been added for soil particle detachment by flow. When tested against the same data set used to validate the original version at the erosion plot scale, predictions made with the revised model gave slopes of a reduced major-axis regression line closer to 1.0 when compared with measured values. The coefficient of efficiency, for sites with measured runoff and soil loss, increased from 0.54 to 0.65. When applied to a new data set for erosion plots in Denmark, Spain, Greece and Nepal, very high coefficients of efficiency of 0.94 for runoff and 0.84 for soil loss were obtained. The revised version was applied to two small catchments by dividing them into land elements and routing annual runoff and sediment production over the land surface from one element to another. The results indicate that, when used in this way, the model provides useful information on the source areas of sediment, sediment delivery to streams and annual sediment yield.