基于植被生态需水的区域水资源结构调整

通过确定泾河流域各类植被生态需水定额,再利用面积定额法计算生态需水量,对植被需水量、需水结构和单位面积需水量进行分析.结论如下:林地适宜生态需水量为341 773.23×104 m3,草地需水569 705.99万m3,农作物需水740 543.20万m3.其中农作物以小麦、玉米、各种谷物、蔬菜瓜果类需水最多.作物需水占植被总需水量的近一半,但作物生态效益远远小于林地和草地,其中还有一部分耕地为坡耕地.泾河流域不同的林、草、农作物比例和农作物种植结构,使得各县植被单位面积需水量和农作物单位面积需水量差异很大.前者的最大值在泾阳县,为5 339 m3/hm2,最小值在环县,为2 082 m3/hm2,平均值为3 081m3/hm2 ;后者的最大值在泾阳县,为5 682 m3/hm2,最小值在定边县,为4 022 m3/hm2,平均值为4 583m3/hm2.基于以上计算与分析,提出泾河流域水资源调整的对策为:以系统论为指导,实现生态环境与经济的协调发展;通过调整农作物、林地、草地种植结构和调整农作物内部结构是实现水资源合理配置重要一环,退耕还林还草,尤其是增加草地种植比例,提高林地、草地的覆盖度,是改善泾河流域生态环境的根本出路;多角度实施农业节水;树立流域系统协调发展观念,完善流域综合管理机制;进一步完善与解决相关科学问题.     

江淮部分地区麦田日本看麦娘对精噁唑禾草灵的抗性及其交互抗性

江淮地区是我国重要的小麦产区之一。为明确该地区麦田日本看麦娘对精噁唑禾草灵的抗性情况,采用整株水平生物测定法检测了该地区的10个种群对精噁唑禾草灵的抗性水平;扩增和比对了高抗种群（AH-40、JS-19）、中抗种群（AH-41、JS-20）与敏感种群（AH-7）的ACCase CT区域基因片段差异,并测定了GSTs、P450s酶抑制剂对精噁唑禾草灵的增效作用及4个抗性种群对8种除草剂的抗性。结果表明,高水平抗性种群数量占供试种群总数的50%,抗性指数为13.14~18.54;测序结果表明,高抗和中抗种群中均未发现已报道可引起靶标抗性的位点突变。AH-40种群在施用GSTs代谢酶抑制剂（灭草环、三聚氯氰、NBD-Cl）和P450s酶抑制剂（PBO、马拉硫磷）后均可显著提高其对精噁唑禾草灵的敏感性,增效倍数分别为1.68、1.68、2.45、1.64、2.03;JS-19种群在施用GSTs酶抑制剂（灭草环、三聚氯氰、NBD-Cl）后GR₅₀有所下降,增效倍数为1.71、1.94、1.71;供试酶抑制剂未对其他抗性种群产生明显增效作用。抗性检测结果显示,4个抗性种群均对炔草酯和甲基二磺隆高抗,AH-41、JS-19高抗高效氟吡甲禾灵,JS-20高抗烯禾啶,但均对唑啉草酯、啶磺草胺、氟唑磺隆和异丙隆敏感。     

纳板河流域自然保护区河流水文特征分析

依据纳板河流域8个监测断面2005~2011年的流速流量水文资料以及1∶50 000地形图,对该流域的水系特征、河道特征、降水以及径流等进行分析。结果表明,河流平均比降大,从上游河段向下游河段逐渐递减,上游河段的比降为84.4‰,下游河段为10.9‰;流域降雨丰富,但空间分布不均,南部、西南部、西部的山顶和山脊附近地区降雨最多,年降水量为2 400 mm左右;径流主要受降水影响,表现出年际变化和季节变化大的特征,最大年径流量为最小年径流量的2.13倍,最大月径流量为最小月径流量的6~12倍。     

晋江西溪流域绿水蓝水资源量估算及分析

运用SWAT模型计算了东南沿海晋江西溪流域的绿水蓝水资源量。对西溪流域绿水蓝水的组成和时间分布规律进行了研究,并分析了西溪流域与中国北方两流域在绿水占水资源比例上的差异。研究结果表明:(1)西溪流域1973—1979年绿水蓝水资源总量是传统水资源量的1.6倍;(2)绿水蓝水的年内分布特点为汛期最高,冬季最低,且绿水流是绿水的主要组成部分;(3)由于气候湿润、干燥度指数较小等原因,晋江西溪流域水资源以蓝水为主,约为绿水资源量的1.8倍;但也表明即使在南方地区,绿水资源仍是水资源的重要组成部分,应予以重视。     

湖北丹江口水库库区小流域土壤可蚀性特征

土壤自身的可侵蚀性是土壤侵蚀发生的内在因素。由于具有明确的物理意义和方便的测定方法,土壤可蚀性K指标值成为水土流失预报模型的一个重要参数。采用EPIC中土壤可蚀性K值计算方法,对丹江口水库库区内1.94km2的五龙池小流域的K值进行了计算。结果显示,研究区内土壤可蚀性K值平均为0.0302thm2h(MJmmhm2)-1,与我国其他有黄棕壤分布地区已有的研究结果相一致。小流域土壤可蚀性存在一定的空间变异,但变异性不大(变异系数14.7%),86.56%土地面积上的K值位于0.0264～0.0330之间。从土壤可侵蚀性强弱判断,该区土壤为易侵蚀土。利用反距离权重插值(IDW)进行了K值图的制作,并简要介绍了K值图的应用。     

Application of the EROSION 3D model to the CATSOP watershed, The Netherlands

This paper describes the application of the EROSION 3D soil erosion model to the CATSOP catchment in the Netherlands using data of 10 storms from the period of 1987 to 1993. Based on observed runoff data the model was calibrated by adjusting initial soil moisture. The computations result in a raster map showing the spatial pattern of predicted erosion and deposition within the catchment. The map corresponds qualitively well with reality. For a quantitative evaluation, the model results were compared with observed sediment data measured at the channel when it leaves the catchment. The comparison shows that simulated soil loss was generally too high. This discrepancy might be caused by weak input data and the presence of processes—such as erosion and deposition within the channel—which are not covered by the model.     

Nitrogen balance and losses through drainage waters in an agricultural watershed of the Po Valley (Italy)

Sustainable agriculture requires assessments of nitrogen fluxes and monitoring of potential nitrate losses. Watershed studies are particularly valuable to calculate nitrogen balances and quantify the relative importance of different sources of inputs and outputs. A nitrogen balance was calculated from September 2004 to October 2006 in an agricultural watershed named Valle Volta (Northern Italy) located in a Nitrate Vulnerable Zone. The area, consisting of 17.4 km² of arable land, with limited presence of urban areas and roads, is entirely below the sea level (3 m b.s.l. in average). Soils are typically Vertic Cambisols and Thionic Fulvisols with fine texture (silty clay or silty clay loam). About 45% of the agricultural soil is pipe-drained. The ground water level is maintained at 4.6 m b.s.l. by the activity of pumps that raise excess waters into a river. Water fluxes in and out from the basin were daily registered, and dissolved inorganic nitrogen concentration (N–NO₃ + N–NH₄) analyzed periodically. Data about fertilizers applications, seeds and crop yield were obtained from farmers’ interviews. Biological nitrogen fixation (BNF) was estimated on the base of dry matter yield. Major N inputs derived from fertilizers (174–188 Mg watershed⁻¹ year⁻¹), followed by BNF (126–131 Mg watershed⁻¹ year⁻¹). Maize was the crop receiving the highest fertilization rates, accounting for more than 40% of total fertilizer inputs. Saleable products were the main form of N leaving the watershed (317–338 Mg watershed⁻¹ year⁻¹). Nitrate was the main N form in irrigation and efflux water; its concentration was higher from autumn to spring, with peaks of 10–20 mg N L⁻¹ in efflux water, while it was low in summer. Nitrogen losses with efflux water were higher in spring and in autumn. Overall, losses of nitrate by efflux water were limited if compared with literature data. Water balance in the area remained near zero at the beginning and the end of the first year, confirming the suitability of the area for this kind of study. The potential net contribution of each hectare of agricultural soil of Valle Volta basin to the N load toward the Adriatic sea is about 5.5 kg N. Our study demonstrated that in the Valle Volta watershed, total N outputs and inputs are of similar magnitude, indicating that crop management and especially N fertilization techniques has reached good levels of ecological sustainability.     

作物病害图像中重叠病斑分离算法

针对传统的分水岭分割算法的不足,应用了一种基于标记测地重建的分水岭算法对棉花重叠病斑图像进行分离.首先对病斑二值图像利用多尺度距离变换获得病斑的距离图像,通过极限腐蚀操作检测出标记种子;然后以种子标记为基础.运用形态学测地重建运算获取测地影响区骨架SKIZ--分水岭线;最后利用分水岭线与原病斑图像进行交集运算.从而得到分离的图像.运用该算法对棉花重叠病斑图像进行分离,试验结果表明:该方法能较好地将图像中的重叠病斑分离,并较好地保存病斑边缘信息,对图像中的微小结构和噪声不敏感,具有良好的鲁棒性.     

基于分水岭算法的绿色作物与背景分割研究

分水岭算法作为彩色图像分割手段的一种方法,具有运算简单,性能优良,能较好提取运动对象轮廓和准确得到运动物体边缘等优点。应用分水岭算法研究了绿色作物及其背景的分割,首先通过数码相机拍摄的一幅640×480田间青菜真彩色图像,在matlab中采用分水岭分割算法处理图像后提取其绿色分量,再用数学形态学闭运算处理后可以较好地分割绿色作物与背景。针对结果中存在的过分割现象,采用先计算图像的形态学梯度,再用分水岭算法分割可以使结果得到有效改善。     

The effects of spatial variability of land use on stream water quality in a costal watershed

Researchers generally accept that land use types within a watershed closely relate with the water quality characteristics of streams. Despite numerous studies investigating the relationships between water quality and land use, there are increasing concerns about the geographical variation and lack of spatial integration in previous studies. We investigated the relationships between land use and water quality characteristics including biological oxygen demand (BOD₅), total nitrogen (TN), total phosphorus (TP), and Escherichia coli in the Wha-Ong estuarine reservoir watershed in Korea, which has spatially integrated land uses. Residential and paddy areas appear to be positively and negatively correlated, respectively, with degraded water quality. The spatial variations of these relationships were also examined using zonal analysis. Some results contrasted with those of previous studies that were conducted mostly in developed Western countries and may reflect the different land use intensities and agricultural practices in Korea. Relationships across zones, distinguished by distances from streams, were inconsistent and erratic, suggesting that the relationships between remote land uses and water quality may be affected more significantly by sub-basin characteristics than by the land use itself. The geographical differences and spatial variations found in this study indicate that caution must be taken in generalizing the relationship between land use and water quality.