Changes in Agricultural Land Use Affecting Future Soil Redistribution Patterns: A Case Study in Southern Tuscany (Italy)     

Marta Debolini  Jeroen M. Schoorl  Arnaud Temme  Mariassunta Galli  Enrico Bonari 《Land Degradation \u0026amp; Development》2015,26(6):574-586

Land‐use changes (LUCs) can be defined as the result of the direct action of the stakeholders in a particular area and natural or human driving forces. LUCs can influence various processes within the landscape and can have an impact on landscape functions. An analysis of the impact of LUCs on landscape processes can help to focus future rural policies. LUCs in Mediterranean areas particularly affect landscape functions because of their agro‐pedoclimatical characteristics. The aims of this work are as follows: (i) to characterise LUCs in the last 11 years in a typical Mediterranean area, the Trasubbie river basin (southern Tuscany, Italy); (ii) to extrapolate these changes and create spatially explicit LUC scenarios for the near future; and (iii) to simulate how and where the predicted LUCs may affect soil redistribution. We carried out an analysis of LUCs within the study area and used the trends to propose alternative scenarios for 2013. For these years, we spatially allocated land use (using the Conversions of Land Use and its Effects model) and used a landscape process model (landscape process modelling at multi‐dimensions and scales) to assess soil redistribution patterns. Land use in the study area changed almost linearly between 1996 and 2007, with cereals and annual fodder crops decreasing, and vineyards, perennial pastures and land abandonment increasing. Our LUC scenario extrapolates these dynamics to make predictions for 2013. A comparison of LAPSUS results between LUC and baseline scenarios for 2013 showed an increase in terms of net soil loss and total erosion, and a decrease in terms of sediment delivery ratio. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

液压脉动衰减器的动态品质     

刘苍山  王科社 《农业机械学报》1993,24(2):19-23

用集中参数法根据液压系统中流量脉动与压力脉动的关系提出了能够准确反映液压脉动衰减器动态品质的概念——液压脉动衰减函数,由此得出关于液压脉动衰减器的一般设计原则,据此对涡流型液压脉动衰减器进行了理论分析和实验研究。  相似文献   

考虑非达西流情况下地下水向集水建筑物运动的非稳定理论的研究     

王鹏举 《灌溉排水学报》1996,(4)

在考虑到承压含水层完整井附近同时存在着非达西流区域和达西流区域、并假定非达西流区域的渗透规律可用Ｆｏｒｃｈｈｅｉｍｅｒ方程描述的基础上，通过求解非稳定渗流方程，得到了该情况下两个不同区域中的解析解，并且针对具体情况下的解析解及其物理意义进行了讨论。同时应用该理论，还得到当ｒ→∞或ｔ→∞时，相应于达西流区域的井函数趋于泰斯曲线，而对于非达西流区域，井函数曲线趋于泰斯曲线的条件是时间取较小值。  相似文献   

基于DNA遗传算法的大坝安全组合     

郭航忠  方海挺  梁月英 《中国农村水利水电》2006,(11):89-91

大坝安全的组合优化监控模型实际上为一带约束的优化问题，将DNA遗传算法应用于大坝安全监控领域中，用罚函数法将有约束的优化问题转换为无约束的优化问题，建立了大坝安全监控的组合优化模型。实例计算表明，该方法是可行的，所建立的组合优化模型在拟合与预报精度上要优于单一的模型。  相似文献   

Comparative functional characterization of canine IgG subclasses     

Lisa M. Bergeron  Erin E. McCandless  Steve Dunham  Bill Dunkle  Yaqi Zhu  John Shelly  Sandra Lightle  Andrea Gonzales  Graeme Bainbridge 《Veterinary immunology and immunopathology》2014,157(1-2):31-41

To date, very little is known about the functional characteristics of the four published canine IgG subclasses. It is not clear how each subclass engages the immune system via complement-dependent cytotoxicity (CDC) or antibody-dependent cell-mediated cytotoxicity (ADCC), or how long each antibody may last in serum. Such information is critical for understanding canine immunology and for the discovery of canine therapeutic monoclonal antibodies. Through both in vitro and ex vivo experiments to evaluate canine Fc's for effector function, complement binding, FcRn binding, and ADCC, we are now able to categorize canine subclasses by function. The subclasses share functional properties with the four human IgG subclasses and are reported herein with their function-based human analog. Canine Fc fusions, canine chimeras, and caninized antibodies were characterized. Canine subclasses A and D appear effector-function negative while subclasses B and C bind canine Fc gamma receptors and are positive for ADCC. All canine subclasses bind the neonatal Fc receptor except subclass C. By understanding canine IgGs in this way, we can apply what is known of human immunology toward translational and veterinary medicine. Thus, this body of work lays the foundation for evaluating canine IgG subclasses for therapeutic antibody development and builds upon the fundamental scholarship of canine immunology.  相似文献   

羟基-D_3的生理功能和机理研究   总被引：3，自引：0，他引：3  

张艳梅 《山西农业科学》2006,34(2):76-78

维生素D3及其活性代谢物25-羟基D3和1,25-羟基D3对畜禽营养具有很重要的意义。从它们的生理功能、代谢过程、作用机理和在畜禽养殖中的应用系统地进行了探讨。  相似文献   

国家南繁育制种基地正规化建设的关键问题分析(英文)     

陈冠铭  ;林亚琼  ;李劲松  ;汪李平 《农业科学与技术》2014,(9):1450-1456

通过对南繁科技性与历史性、海南南繁不可替代性、南繁功能价值层次结构以及存在的关键问题进行分析,得出南繁已上升为国家战略,成为国家战略性资源。海南南繁作为科研实践与历史的选择的重大成果,在气候条件、科学育种、粮食生产抗灾救灾、保障种业安全和区位优势等方面发挥着不可替代的作用;同时通过引入价值工程、产业集群、区域经济等理念,在研究南繁的功能、价值和存在的关键问题基础上,建立南繁功能价值的层次结构。但要实现南繁产业集群化发展,充分实现南繁功能价值,必须要解决南繁在顶层规划、试验用地、制度设计、硬件建设和生态安全等方面存在的关键问题。提出了建设南繁育种科研核心保护区、完善南繁法规政策保障机制、健全南繁管理体制、编制实施南繁育制种基地发展规划、争取国家政策资金支持等建议。  相似文献   

沙化对向海湿地功能的影响     

李鱼  张华鹏  刘亮  王月  孙亚红  李兴春  李青山 《水土保持通报》2005,25(2):83-86

以向海国家自然保护区为例,简要阐述了区内湿地沙化的现状、原因及其对湿地功能的影响。研究表明,人类不合理的开发是造成向海湿地沙化的主要原因。沙化对湿地功能,诸如洪水调控、污染物净化以及提供动植物栖息地等造成了不同程度的破坏。提出了湿地恢复、水资源合理利用等沙化治理和湿地资源可持续开发利用的对策与方案。  相似文献   

向海国家级自然保护区湿地功能研究   总被引：17，自引：0，他引：17  

翟金良  何岩  邓伟 《水土保持通报》2002,22(3):5-9

向海国家级自然保护区具有重要地位 ,湿地是向海国家级自然保护区景观的重要组成部分。对向海国家级自然保护区湿地的功能从生态环境功能和资源功能 2个方面进行了分析和探讨。其中生态环境功能主要包括生物多样性维系功能、水文过渡带功能和高效滤过截留作用等方面 ,资源功能主要包括水土资源环境功能、生物资源环境功能、休闲娱乐和科研宣教及社会人文价值功能等方面  相似文献   

A method for prediction of soil penetration resistance   总被引：1，自引：2，他引：1  

A.R. Dexter  E.A. Czy  O.P. Ga&#x;e 《Soil & Tillage Research》2007,93(2):412-419

A new equation for predicting penetration resistance of soil is presented. The equation contains two main additive terms: the first is a measure of the degree of compactness of the soil and the second gives the contribution of pore water to the soil strength. It is proposed that these terms are applicable to soils of different texture, at different bulk densities and at different water contents. The equation is calibrated and tested using values of penetrometer resistance measured in the field at a range of locations in Poland. Predictions from the equation are compared with predictions from two other published equations. It is shown that the performance of the proposed equation is superior to the other two, at least for the Polish data set used in this work. On the basis of the assumption that the proposed equation is correct, predictions of penetrometer resistance are made using pedotransfer functions to illustrate typical effects of soil texture, bulk density and water content.  相似文献