不同水肥管理下设施黄瓜地氮素损失及水氮利用效率模拟分析

【目的】利用模型定量分析不同水肥管理对设施菜地氮素损失及水氮利用效率的影响,为设施菜地合理水肥管理措施的制定提供理论指导。【方法】2010—2011年在山东寿光设施大棚设置了4种水肥管理模式：对照+畦灌（CK）、传统施肥+畦灌（FP）、优化施肥+畦灌（OPT）和传统施肥+滴灌（RI）。利用EU-Rotate_N模型模拟了两个生长季（春夏茬和秋冬茬）各处理下设施黄瓜地的产量、氮素淋失和气体损失等,并计算了水氮利用效率。【结果】两个生长季内滴灌处理（RI）比畦灌处理（CK、FP和OPT）节水约60%,且灌溉水利用效率提高了2倍多。在各施肥处理中,春夏茬和秋冬茬黄瓜的氮素气体损失分别占施氮量的16%—19%和6%—11%,氮素淋失量分别占施氮量的14%—57%和20%—55%,其中OPT和RI处理的氮素淋失量比FP处理分别减少了19%—31%和63%—76%。OPT处理两茬黄瓜的氮素利用效率比FP处理分别提高了3%和7%,而RI处理的氮素利用效率比FP处理分别提高了41%和44%。【结论】氮素淋失是设施菜地氮素损失的主要途径,滴灌和优化施肥均能有效地减少菜地土壤硝态氮的淋失,提高氮素利用效率。     

合肥市滨湖新区硝酸盐污染研究

硝酸盐是污染地下水的主要污染物之一,来自农业活动的硝酸盐已成为地下水的主要污染源。采用GIS地统计学方法,结合调查区域土地利用类型的分析,对合肥市滨湖新区85个样点的地下水硝酸盐含量进行分析研究,并分析了NO3^--N的污染特点,提出了相应的防治对策。结果表明：该地区地下水硝酸盐污染较严重,50%以上的区域NO3^--N含量〉20 mg/L;流域内NO3^^--N浓度随地下水深度的增加而逐渐降低。     

空气曝气技术修复石油类污染地下水的影响因素

[目的]研究空气曝气（AS）技术修复石油类污染地下水的影响因素.[方法]选择二甲苯和萘作为典型的石油烃污染物,砾砂、粗砂和中砂作为模拟含水层介质,通过土柱模拟试验研究了不同影响因素下（如曝气量、介质渗透性、曝气方式）空气曝气技术对石油类污染地下水的修复效果.[结果]曝气量和介质渗透性对AS的修复效果有较大影响,污染物的去除效率随着曝气量的增加而增大,但曝气量超过300 ml/min,污染物的去除率不再随曝气量的增加而增加;介质渗透性越强,污染物的去除率越高.对于渗透系数较小的中砂,间歇曝气较连续曝气效果好;对于砾砂和粗砂,2种曝气方式效果相仿.AS在去除污染物的过程中存在明显的拖尾现象.污染物萘不适合采用AS技术去除.[结论]该研究可为AS技术应用提供数据支持.     

基于DRASTIC模型的地下水脆弱性评价方法评述

首先分析了基于DRASTIC模型的地下水脆弱性评价方法,然后探讨了该模型的局限性和缺陷,并评述了改进模型的应用效果,最后对基于DRASTIC模型评价方法的应用前景进行了分析,提出了关于选用和应用该模型需要重点关注的问题和评价成果需实现成果价值最大化。     

农村电力排灌站电气设备最优配置的若干思考

农村电力排灌站电气设备主要是利用电力进行农业用水资源调配的水利设施。笔者根据自身工作经验,主要对农村电力排灌站电气设备最优配置进行了一番分析与研究。     

环境因素和作物生长对稻田CH_4和N_2O排放的影响

采用大田试验方法,研究了常规灌溉和持续淹水条件以及不同水平有机质(小麦秸秆)投放量(0、2.25、4.5t@hm-2)条件下各环境因素(包括土壤温度、灌溉水层深度和土壤Eh)对CH4和N2O排放的影响以及水稻生长与CH4排放的关系.结果表明,在2种水分管理下,CH4的累积排放量均与水稻冠层高度呈显著正相关(P<0.001).连续淹水条件下,无论有无外源有机质投放,稻田CH4排放的季节性变化均与土壤温度呈指数相关(P<0.001),而N2O排放的季节性变化则仅取决于土壤水分条件.     

Soil saturation effects on forest dynamics: scaling across a southern boreal/northern hardwood landscape

Patch modeling can be used to scale-up processes to portray landscape-level dynamics. Via direct extrapolation, a heterogeneous landscape is divided into its constituent patches; dynamics are simulated on each representative patch and are weighted and aggregated to formulate the higher level response. Further extrapolation may be attained by coarsening the resolution of or lumping environmental data (e.g., climatic, edaphic, hydrologic, topographic) used to delimit a patch.Forest patterns at the southern boreal/northern hardwood transition zone are often defined by soil heterogeneity, determined primarily by the extent and duration of soil saturation. To determine how landscape-level dynamics predicted from direct extrapolation compare when coarsening soil parameters, we simulated forest dynamics for soil series representing a range of drainage classes from east- central Maine. Responses were aggregated according to the distribution of soil associations comprising a 600 ha area based on local- (1:12,000), county- (1:120,000) and state- (1:250,000) scale soil maps. At the patch level, simulated aboveground biomass accumulated more slowly in poorer draining soils. Different soil series yielded different communities comprised of species with various tolerances for soil saturation. When aggregated, removal of waterlogging caused a 20–60% increase in biomass accumulation during the first 50 years of simulation. However, this early successional increase and the maximum level of biomass accumulation over a 200 year period varied by as much as 40% depending on the geospatial data. This marked discrepancy suggests caution when extrapolating with forest patch models by coarsening parameters and demonstrates how rules used to rescale environmental data need to be evaluated for consistency.     

Spatiotemporal changes in terrestrial water storage in the Beijing-Tianjin Sandstorm Source Region from GRACE satellites

The Sandstorm Source Control Project in and around the Beijing-Tianjin region was one of the most important ecological projects in China. Terrestrial water storage (TWS) has important impacts on the ecological construction, agriculture, industry, and resident’s lives. Based on the Gravity Recovery and Climate Experiment (GRACE) data, meteorological and Moderate Resolution Imaging Spectroradiometer (MODIS) data, etc., this paper analyzed spatiotemporal characteristics of TWS, groundwater storage, and precipitation, and explored the influencing factors of regional TWS combined with land use and land cover (LULC), social and economic data. The most important results were as follows: (1) From 2003 to 2016, TWS in the Beijing-Tianjin Sandstorm Source Region showed a decreasing trend with a rate of 3.14 mm yr⁻¹. (2) The TWS decline was caused mainly by groundwater overexploitation, but not precipitation variation. (3) Spatiotemporal variations of TWS were related to LULC. The area with the most serious decrease of TWS was mainly located in the southwestern part of the region, where farmland percentage and population density were greater. (4) Reducing the percent of farmland and tree planting, and adding the shrub and grass planting, could be a viable choice for the Beijing-Tianjin Sandstorm Source Control Project. These results provide a scientific basis for regional water resource and ecological management.     

用SahysMod模型研究不同灌排管理情景土壤水盐动态

银北灌区是宁夏土地整治和高标准灌溉绿洲农田建设的重点区域。该区域耕荒地交错分布、土壤盐渍化严重。通过模型分区模拟,在土地整治过程中建立完整、配套的灌排系统是解决区域土壤盐渍化的有效措施。该研究以银北灌区典型区域-西大滩为例,综合考虑荒地与耕地土壤属性的空间变异性,以2015—2016年土壤盐分数据进行率定,2017年盐分数据作为验证,利用SahysMod探索在土地整治过程中不同灌排管理下未来10 a内土壤水盐动态变化。结果表明,现有灌排管理下(即灌水量为670 mm,灌溉水电导率为1.05 dS/m,排水沟深1.5 m),荒地土壤盐分在预测初期(2017—2022年)逐年升高,预测后期(2023—2027年)变化平缓;耕地土壤盐分在预测初期变化缓慢,预测后期逐年增加。加大灌水量是解决土壤盐渍化的一个重要途径,可以有效延迟耕地盐分累积到障碍水平的时间;在灌溉水电导率为0.6 dS/m情况下,未来10 a内耕地都不会受到盐害胁迫;现有灌排管理下,在2024年以后作物生长就会受到盐害胁迫,当灌溉水电导率继续增加时,作物生长受到胁迫的时间相应提前。通过土地整治,加深排水沟深度可以延迟土壤盐分达到障碍水平的时间。在整治过程中深为2.2 m的排水沟,可保证未来10 a内耕地盐分小于1.7 dS/m,区域内玉米可正常生长。研究可为在土地整治过程中的灌排管理及土壤盐渍化防治提供建议。     

灌排模式对稻田作物水足迹的影响

设置浅水勤灌(FSI)、浅湿灌溉(WSI)、控制灌溉(CI)和蓄水控灌(RC-CI)4种灌排模式,于2017-2018年进行了桶栽观测试验,利用作物水足迹计算方法量化蓝、绿、灰水足迹,分析灌排模式对水稻水足迹及其组成的影响.结果表明:在不同灌排模式下,水稻作物水足迹、组成及其效率均存在差异.所有处理水足迹的范围为846...