华北地区冬小麦优化灌溉的水分指标与节水性,抗逆性分析

介绍了冬小麦优化灌溉的水分指标及传统灌溉的区别，并在总结分析试验研究结果的基础上用对比的方法阐述了优化灌溉的节水，节能，抗逆和增产原理。     

Topographic controls on the invasion of Pteronia incana (Blue bush) onto hillslopes in Ngqushwa (formerly Peddie) district,Eastern Cape,South Africa

The role of topographic factors in the invasion of hillslopes by Pteronia incana, an unpalatable shrub, was investigated. The study combined field observations with image analysis based on high-resolution infrared imagery. A Digital Elevation Model (DEM) of 20 m spatial resolution was used to derive terrain parameters. The Topographic Wetness Index (WI), a component of the TOPMODEL, was derived from the DEM and its relationship with the spatial distribution of P. incana was explored. The absence/presence of P. incana was noted to be strongly influenced by slope angle and aspect. The probability for P. incana occurrence increased with slope steepness and southerly slope orientation. Abandoned and grazing lands were identified as the main invasion hotspots on hillslopes. The combined influence of slope gradient and aspect, and land use was noted to have promoted the invasion. This is borne out by the concentration of the invasion on abandoned steep slopes with a southerly orientation.     

Development of Core Subset of Finger Millet Germplasm Using Geographical Origin and Data on 14 Quantitative Traits

Finger millet [Eleusine coracana (L.) Gaertn.] is an important cereal food crop in Africa and South Asia. It is a hardy crop that can be grown in very diverse environments from almost at sea level to about 2400 m.a.s.l. Finger millet has an excellent food value as its seeds contain protein ranging from 7 to 14% and are particularly rich in methionine amino acid, iron, and calcium. Despite all these merits, this crop has been neglected from the main stream of crop improvement research. One of the means to boost its production and productivity is to enhance utilization of finger millet germplasm to breed superior varieties. Keeping this objective in view, a core subset of finger millet germplasm (622 accessions) based on origin and data on 14 quantitative traits was developed from the entire global collection of 5940 accessions held in the genebank at ICRISAT, Patancheru, India. The comparison of means, variances, frequency distribution, Shannon-Weaver diversity index (H′) and phenotypic correlations indicated that the core subset represents the entire collection. These tests indicated that sampling was optimal and the diversity has been captured very well in the core subset. The correlation analysis indicated that panicle exsertion and longest finger length could be given lower priority in the future germplasm evaluation work of finger millet.     

Empirical analysis and prediction of nitrate loading and crop yield for corn-soybean rotations

Nitrate nitrogen losses through subsurface drainage and crop yield are determined by multiple climatic and management variables. The combined and interactive effects of these variables, however, are poorly understood. Our objective is to predict crop yield, nitrate concentration, drainage volume, and nitrate loss in subsurface drainage from a corn (Zea mays L.) and soybean (Glycine max (L.) Merr.) rotation as a function of rainfall amount, soybean yield for the year before the corn-soybean sequence being evaluated, N source, N rate, and timing of N application in northeastern Iowa, U.S.A. Ten years of data (1994-2003) from a long-term study near Nashua, Iowa were used to develop multivariate polynomial regression equations describing these variables. The regression equations described over 87, 85, 94, 76, and 95% of variation in soybean yield, corn yield, subsurface drainage, nitrate concentration, and nitrate loss in subsurface drainage, respectively. A two-year rotation under average soil, average climatic conditions, and 125 kg N/ha application was predicted to loose 29, 37, 36, and 30 kg N/ha in subsurface drainage for early-spring swine manure, fall-applied swine manure, early-spring UAN fertilizer, and late-spring split UAN fertilizer (urea ammonium nitrate), respectively. Predicted corn yields were 10.0 and 9.7 Mg/ha for the swine manure and UAN sources applied at 125 kg N/ha. Timing of application (i.e., fall or spring) did not significantly affect corn yield. These results confirm other research suggesting that manure application can result in less nitrate leaching than UAN (e.g., 29 vs. 36 kg N/ha), and that spring application reduces nitrate leaching compared to fall application (e.g., 29 vs. 37 kg N/ha). The regression equations improve our understanding of nitrate leaching; offer a simple method to quantify potential N losses from Midwestern corn-soybean rotations under the climate, soil, and management conditions of the Nashua field experiment; and are a step toward development of easy to use N management tools.     

Spatial variation of tracer distribution in a structured clay field soil

Within the sensitive soils of the River Oder Basin (E Brandenburg, Germany), chloride‐tracer transport was studied with respect to soil‐surface conditions of the well structured clayey topsoil (disturbed vs. undisturbed) and irrigation mode (flooding vs. sprinkling). The spatial variation of chloride and dye distribution was sampled in a regular grid within different soil depths. Different methods were used for the analysis of spatial heterogeneity: a heterogeneity index HI derived from fitting parameters of the cumulative distribution function, semivariogram analyses to identify the spatial representativity of observations and to classify the spatial variation, and Spearman's rank correlations to examine the spatial similarity of tracer distribution across different soil depths. Soil aggregation was obvious throughout the soil profile, and macropores and fractures were preferred flow paths for the tracer. Flood irrigation resulted in more “uniform” distribution than sprinkling did. However, preferential flow was identified for all treatments, where, once established below the surface layer, flow paths led to heterogeneity indices manifesting nonuniform flow and reduced lateral mixing between macropores and soil matrix. Within the flooded plot, spatial structure of chloride concentration was moderate unlike the strongly structured variation within the sprinkled plots. For purposes to generalize and to assess regional risk of the water and solute transport within the topsoil of the River Oder Basin, spatial autocorrelation ranges of about 15 cm should be considered and included into concepts of soil protection and land‐use management, soil‐sampling strategies, or modeling approaches.     

常州市太湖湾地区采石场景观污染评价与生态恢复研究

江苏省常州市太湖湾地区的废弃采石场已经造成严重的景观污染。使用遥感(RS)和地理信息系统(GIS)技术,获取采石场的特征数据,进而使用景观污染指数对常州太湖湾沿岸废弃采石场的景观污染现象进行定量的景观污染评价,筛选出已造成严重景观污染的废弃采石场,为决策管理部门合理安排整个废弃采石区的生态恢复工作提供了科学依据。通过对该区废弃采石场的现场实地调查,制定出该区生态恢复工程的系统集成技术；根据生态恢复植物品种筛选原则和本地采石场废弃采石壁出现的先锋植被情况,选择了用于生态恢复的植物品种并分别对该区27个废弃采石场提出5种不同的生态恢复方案。     

水资源承载力评价指标体系研究

水资源承载力涉及到整个资源、经济、环境大系统 ,水资源承载力与社会、经济、环境可持续发展是否协调是全球关注的重大问题。在充分理解水资源承载力概念、水资源承载力影响因素的基础上建立了水资源承载力评价指标体系及评价方法 ,并以典型缺水的关中地区为例进行了研究 ,得到了关中水资源可持续利用的满意方案     

台湾省植被NDVI随海拔高度的变化及其气候响应

[目的]揭示台湾省陆地植被生态系统随海拔高度的变化趋势及其响应程度,为区域可持续发展、生态环境保护提供理论依据。[方法]基于台湾省1998—2018年SPOT/VEGETATION NDVI卫星遥感数据、气象及DEM数据,结合相关分析法、回归分析法等数理统计方法,对气候变化下的台湾省植被归一化植被指数(NDVI)变化趋势及区域响应进行了分析。[结果] 1998—2018年台湾省植被NDVI均值增长率为5.09%;台湾省不同高程范围所占的面积比例差异较大,500 m区域的面积比例高达52.49%,3 600 m区域的面积比例仅为0.01%,且NDVI均呈现较低值,分别为0.72和0.73;1998—2018年台湾省海拔除3 600 m外,其他海拔高程范围NDVI均值增长明显(p0.001);在500～3 600 m高程范围内,NDVI年均值与气温、降雨相关关系显著(p0.05)。[结论]海拔越高,植被生长状况对降雨的变化较气温更为敏感。