不同有机物料对黑土及其复合胶体比表面积和电荷性质的影响

通过盆栽试验研究了施用动物粪便、动物残体、草本残体、木本残体4种不同有机物料对黑土胶体及黑土阳离子交换量(CEC)的影响。结果表明:不同来源有机物料对黑土胶体及黑土CEC的影响存在差异。与CK相比,动物粪便处理下黑土胶体比表面降低7.33%,而动物残体处理下提高了59.58%,木本残体提高了57.46%,草本残体提高了100.18%。pH<6时,各处理土壤胶体表面可变电荷量(Q表面)的曲线大致相似;在pH>6时,各有机处理土壤胶体样的表面电荷(Q样)均高于CK,并且动物粪便与木本残体的Q表面曲线相似且数值较高,CK与动物残体Q表面的曲线大致相同且数值较低。在pH为8～10时,各处理Q样由大到小依次为:动物粪便>木本残体>动物残体>草本残体>CK,动物粪便土壤胶体参比的表面电荷(Q参)与动物残体Q参的曲线大致相同并且数值较高,CK与草本残体Q参曲线相似且数值较低。不同来源有机物料对黑土CEC的影响也有所不同,动物粪便、动物残体、木本残体显著提高黑土CEC,而草本残体作用不明显。     

基于生态足迹的资源型城市可持续发展能力分析——以山西省晋城市为例

以新型城镇化进程中典型资源型城市——晋城市为研究对象,采用生态足迹综合法账户模型,以2004—2013年共10 a的生物资源平均产量作为动态参照,选取了较新的均衡因子,利用NPP（净初级生产力）客观合理地确定了各土地类型产量因子,在此基础上对晋城市2004—2013年的生态足迹进行了计算,并引入单位万元GDP生态足迹、生物多样性指数、生态足迹发展能力和生态压力指数四项指标,多方面综合分析了晋城市的可持续发展能力。研究表明:2004—2013年晋城市人均生态足迹呈递增趋势,人均生态承载力略微减少,生态赤字呈现上升趋势,单位万元GDP生态足迹逐年减少,生态多样性指数基本保持不变,生态经济系统发展能力有所提高,生态压力不断增大。其主要原因为人口总量增加、经济增长带动消费水平提高、能源需求所占比重较大以及土地利用效率较低。据此,提出优化产业结构,提高土地利用效率,控制人口规模,保护生态环境的对策以提高晋城市可持续发展能力。该研究在一定程度上丰富了城市生态安全研究案例,为经济发展转型中的资源型城市可持续发展提供决策依据。     

Maintaining estuary quality for shorebirds: towards simple guidelines

It is increasingly important to be able to monitor and maintain the quality of estuaries for overwintering shorebirds. Bird numbers alone are not sufficient to indicate quality nor, as recent research shows, can it be assumed that site quality is being maintained simply because there is enough food to meet the birds’ physiological demands; i.e., the amount of food available per bird in autumn needs to be greater than the amount eaten. But how much greater? We used a simple individuals-based and behaviour-based model to explore the factors that affect the relationship between overwinter mortality and the amount of food available per bird in autumn (the food:bird ratio). The aims were to explore how the natural history characteristics of a shorebird species affected the shape of this relationship, in order to identify characteristics of the system that should be included in any monitoring programme of site quality. In all cases there was a minimum threshold food:bird ratio above which mortality did not vary and below which mortality increased steadily. The amount of food per bird required at the threshold varied from one to six times the amount actually consumed by each bird during winter, depending on the amount of realism included in the model. The minimum threshold ratio was most strongly influenced by the shape of the relationship between intake rate and prey density - the functional response - and, when interference competition occurred, by the distribution of the birds’ main food supply. Simulations with realistic spatial distributions of prey predicted that the minimum required amount of food per bird would be between two and five times the amount actually consumed. The threshold approach could provide a simple method of monitoring estuary quality based on food supply and bird numbers. It also provides a potentially clearly-defined and unambiguous measure of the carrying capacity of a site. If applied to a sufficient number of real estuaries, general guidelines for maintaining estuary quality based on estuary characteristics, food supply and bird species might be established.     

河西内陆区十二五农业节水途径及节水潜力分析

河西内陆区气候干旱,水资源短缺,经济、社会、生态系统用水矛盾突出。随着人口的持续增长和社会经济的快速发展,经济生态系统之间的用水矛盾日益尖锐,黑河、石羊河、疏勒河下游均相继出现了土地沙化、农田荒芜、植被枯萎、湿地萎缩等严重的生态环境问题。结合“十二五”农业节水规划,分析了不同农业节水措施和水平对生态系统的作用和支撑能力,对制定生态系统建设规划具有重要参考作用。     

区域水资源承载力研究理论与方法

水资源是基础性的自然资源和战略性的经济资源,成为可持续发展的限制性因素,研究水资源承载力可以为推动社会、经济、生态环境全面协调可持续发展起到重要作用。本文对目前水资源承载力的概念、研究理论、方法和进展进行了全面的阐述,并提出了水资源承载力研究中存在的问题,指出了今后研究发展方向,为水资源承载力的进一步深人研究提供参考。     

动态水环境容量研究——以潇河流域为例

传统的水环境容量以90%设计枯水流量为计算条件,存在水文计算条件单一、水环境容量不易管控等缺点。考虑河道流量与入河污染物影响下的水环境容量逐月变化,提出了基于水文过程与污染源变化条件下的动态水环境容量与入河污染管控计算方法。以山西潇河流域晋中段为例,计算了研究流域两水功能区的逐月水环境容量及其余量,运用MIKE11模型计算了逐月允许的动态入河污染负荷。研究结果表明:(1)2019年水功能区A的COD和氨氮水环境容量阈值分别为138.37~216.54 t和6.38~14.19 t,7-10月水环境容量较大;水功能区B的COD和氨氮水环境容量阈值分别为417.67~821.05 t和9.32~29.49 t,5-8月份水环境容量较小。(2)在满足水功能区目标水质的基础上,2019年水功能区A允许的入河负荷均大于现状入河量,汛期COD和氨氮容量余量较多;水功能区B在1月、2月应削减氨氮0.003、0.086 t;削减COD 0.05、0.143 t,4-7月份允许的污染负荷大于实际入河量,余量较多。计算的动态水环境容量能够客观反映变化水文条件下的水环境容量及其余量实际,给出了满足河道水质目标前提下的入河污染物允许阈值,为流域水环境保护与管理提供重要参考和新思路。     

棉花群体叶面积载荷量与产量关系及对源的调节效应研究

通过对棉花单位叶面积负载的生殖器官量的研究结果表明：较高的叶面积载荷量［以单位叶面积负载的果节数（个／ｍ２叶）、结铃数（个／ｍ２叶）及生殖器官干重（ｋｇ／ｍ２叶））能够促进棉花群体叶片光合强度提高和养分向棉铃输送增多，因而群体成铃数增多，产量提高。同时由剪叶、疏蕾试验揭示了，当群体叶面积系数控制在适宜范围内，可通过提高叶面积载荷量使产量进一步上升，群体叶面积系数过大时，通过减少叶面积，提高叶面积载铃量可以使产量增加。而当叶面积过小时，虽叶面积载荷量增大，但终因光合面积太小，产量下降，因此叶面积载荷量可作为反映棉花群体源库是否协调及改进栽培技术的依据。     

Seed priming and soil incorporation with silicon influence growth and yield of maize under water-deficit stress

Silicon (Si) has been known to enhance plant tolerance against biotic and abiotic stresses besides its beneficial effects on plant growth and yield. Two experiments were conducted to evaluate the effect of Si against water-deficit stress in maize (Zea mays) applied through seed priming and soil incorporation methods, and to find out the optimum dose of Si under each method. In the seed priming experiment, seeds were exposed to different Si levels, up to 2 mM l^–1, germinating under three soil moisture regimes (100%, 75% and 50% field capacity-FC). In the soil incorporation study, the treatments included were six Si doses from 0 to 600 kg ha^–1 under the same soil moisture regimes. Grain yield was reduced by 59% and 69% in the seed priming and soil incorporation study, respectively, at 50% FC. Si application was effective irrespective of the application methods with higher cob length, 100-kernel weight and grain yield than the control. Application of Si at 1 mM l^–1 as seed priming and 300 kg ha^–1 as soil incorporation was more effective than other doses and could be recommended as optimum dose for Nakhon Sawan 3 hybrid maize variety under water-deficit stress.     

基于RAGA一PPPCA模型的区域农业水土资源承载力综合评价

在全面分析影响农业水土资源复杂系统承载力变化诸多因素的基础上,初步提出了农业水土资源承载力的概念,选取27个与农业水土资源密切相关的承载力评价指标,为了解决评价指标过多引起的评价过程复杂性问题,将主成分分析法有效解决指标间多重相关性的特性和投影寻踪模型高效降维技术有效结合在一起,提出了投影寻踪主成分分析模型。将该模型应用于三江平原农垦建三江分局农业水土资源承载力综合评价中,取得了满意的结果,同时为农业水土资源承载力评价研究提供新的研究思路和研究方法。     

Nutritional (Fe-Mn) interactions in ‘Big Top’ peach plants as influenced by the rootstock and by the soil CaCO3 concentration

Manganese (Mn) toxicity in plants is often not a clearly identifiable disorder and it can interfere with the absorption, translocation, and utilization of other elements such as Ca, Mg, Fe, and P. Soil conditions, management factors, and the use of different genotypes of rootstock can determine the degree of Mn toxicity and of interaction with other elements in the orchard. Five plants of the cultivar ‘Big Top’® grafted onto itself, onto plum rootstock ‘Mr.S.2/5’ and onto hybrid peach x almond rootstock ‘GF677’ were grown in 25-L containers under three treatments, 0, 20, 30% concentration of total lime, obtained by mixing powdered CaCO₃ to a sandy soil. Plants were fertilized with manure and a solid fertilizer early in April and irrigated in summer periodically with water rich in manganese. After just 28 d, active lime caused a decrease of chlorophyll SPAD index especially in plants grafted on itself, while those grafted on the tolerant ‘GF677’ rootstock behaved better than those grafted on ‘Mr.S.2/5.’ From June to September, irrigation caused increases in soil Mn concentration and Mn concentration in control plants. This caused first a serious defoliation in Big Top / Big Top plants and then a re-greening of cultivar grafted onto ‘Mr.S.2/5’ and ‘GF677,’ probably due to the interaction between iron and manganese at high pH. In particular the 20% CaCO₃ addition to the soil preserved the plants of cultivar grafted onto ‘Mr.S.2/5’ from Mn toxicity, as shown by their high chlorophyll content and growth and lower Mn leaf concentrations. Plants grafted onto ‘GF677’ rootstock showed the best behaviour under 30% CaCO₃ treatment associated to higher Fe(III)-reducing capacity and photosynthetic activity. Rootstocks and soil conditions (lime and waterlogging) influenced mineral status and growth of the peach cultivar ‘Big Top,’ particularly by interacting together and modifying Fe-Mn availability.