土壤是产生N2O的最主要来源之一。硝化和反硝化反应是产生N2O的主要机理，由于硝化和反硝化微生物同时存在于土壤中，因而硝化和反硝化作用能同时产生N2O。N2O的来源可通过使用选择性抑制剂，杀菌剂以及加入的标记底物确定。通过对生成N2O反应的每一步分析，主要从抑制反应发生的催化酶和细菌着手，总结了测量区分硝化、反硝化和DNRA反应对N2O产生的贡献方法。并对15N标记底物法，乙炔抑制法和环境因子抑制法作了详细介绍。

非点源污染最主要的影响就是使水体富营养化、水质变差，从而影响到生产、生活、社会与经济的发展，其中氮、磷的农业非点源污染又是最主要的。经过3O多年的研究，非点源污染研究逐渐从初期的定性化研究转向定量化，由统计、调查与机理研究转向实用治理研究。就众多的防治方法来看，大体可以分为两大类，即“源”（Source）防治和“汇”（Sink）防治。

In most cases, rice production is associated with flooding irrigation and the efficiency of irrigated water use (WUEi) is generally lower for production of rice than for other crops. We have examined the effects of various irrigation regimes on water consumption in a well-puddled paddy field, as well as on dry matter production, grain yield and physiological responses of the plants. Four sets of conditions were studied, with two replications, in the well-puddled paddy field: Continuous flooding irrigation treatment (CSF); three intermittent irrigation treatments, designated Ⅱ-0, Ⅱ-1 and Ⅱ-2, in which plants were re-irrigatedwhen the water potential of the soil fell below0, 10, and -20 kPa at a depth of 5 cm, respectively. Water consumption was lower during Ⅱ-0 than during CSF because the percolation rate was reduced by the reduction in the hydraulic head of the ponded water. Intermittent irrigation led to the repeated shrinking and swelling of soil during Ⅱ-1 and Ⅱ-2 and, therefore, soil cracks developed rapidly. Since they became the major routes of water percolation, these soil cracks increased water consumption during Ⅱ-1 and Ⅱ-2 above that during CSF and Ⅱ-0. There were no significant differences in dry matter production and grain yield between CSF and Ⅱ-0, but both were significantly greater than in the case of Ⅱ-1 and Ⅱ-2. Therefore, WUEi increased in the following order: Ⅱ-0, CSF, Ⅱ-2, Ⅱ-1, although the difference was very small between Ⅱ-1 and Ⅱ-2. A lower crop growth rate (CGR) resulted from a decrease in the net assimilation rate (NAR) during II-1 and Ⅱ-2, and there was also a reduction in the leaf area index (LAI) during Ⅱ-2. Early senescence with ripening and water stress around midday decreased the rate of photosynthesis in leaves, causing the lower NAR. These physiological responses of the plants were responsible for the reduction on the dry matter production and grain yield in the intermittent irrigation.

比较混凝、过滤与微絮凝直接过滤三种工艺对生活污水主要污染物去除率指标的差异，得出了微絮直接过滤工艺处理生活污水的可行性在该工艺运行的最佳条件下，污水中的cODc 、TP、NH。一N 以及浊度的去除率分别为83.37% 、84.51、48.80和85.99从各污染物去除的机理分析表明，微絮凝直接过滤工艺中的过滤，实质上是混凝过程的连续，是一种特殊形式的絮凝作用具有上向流和下向流的过滤装置激发了过滤效果，过滤在该工艺中对污染物的去除贡献占8O～88粒径较粗且均匀的河沙滤料的使用，避免了滤料的大量流失和滤料结块。

举文讨论了土壤水分运动与作物生长动态耦合模型的建立方法经与试验结果比较，验证了土壤水分运动和作物生长动态耦合模型对冬小麦生长过程模拟的可靠性，分析了模型中有关作物旱害和渍害耦合参数的灵敏性应用该模型对南方多雨地区冬小麦生长进行的分析。