Sensitivity to information upscaling of agro-ecological assessments: Application to soil organic carbon management

Upscaling of agro-ecological indicators applied in regional analyses is sensitive to scale issues of the input data. This study develops a methodology to quantify this sensitivity for an indicator of soil organic carbon (SOC) dynamics at the farming system level. A reference case consists of seven fully described farms in northern Italy. Both upscaling in complexity by substituting measured input with estimated input and upscaling in space by extending the methods to farms not included in the reference case are addressed. The indicator increased with 3-107% at four farms after substituting measured management input with that estimated by an expert, whereas it remained unchanged or decreased at the other three farms. Taking the modal value from a cluster of pedological input did not lead to additional uncertainty in most cases, and only slightly increased it in others. We evaluated spatial upscaling by including 733 farms divided in 18 clusters that were described with less information as compared to the reference farms. Within each cluster, we observed relevant variability of the indicator (coefficients of variation of 12-43%), as a consequence of the heterogeneity of farms comprised in each cluster. In each cluster we calculated the indicator for one virtual farm, defined by using modal values for basic farm inputs. In this case the indicator was highly correlated (R² = 0.98) with the average of the values obtained using measured basic farm inputs. We conclude that upscaling in complexity and space introduces uncertainty in the values of the indicator compared to the reference case. The extent of such differences depends on the variability of the systems under analysis and on indicator sensitivity.     

Agricultural intensity and its measurement in frontier regions

Agricultural intensification is a process of raising land productivity over time through increases in inputs of one form or another on a per unit area basis. Its study is important for several reasons, many of which relate to agroforestry objectives. However, the concept of intensification often is poorly defined in the literature and existing methods and approaches to measuring agricultural intensity are problematic, making it difficult to precisely compare particular farming systems. This paper examines the concept of agricultural intensity, its relevance to efficient and sustainable land use, and the ways it can be measured. A review of existing approaches and methods for measuring intensity, such as those based on output, cropping frequency, and agrotechnologies, revealed that these feature a number of problems. Some of these problems relate simply to imprecision and inaccuracy. But others are due to the unsuitability of these approaches in the context of farming environments, such as frontiers, which are characterized by limited production data; unconventional cropping cycles; myriad production strategies, cropping patterns, and crop-fallow cycles on a single farm; and a high level of system dynamism and production variability over time. A modified approach to measuring agricultural intensity, based on fieldwork in Petén, Guatemala, is presented. This approach, which is better suited to frontier regions, employs an agricultural intensity index to help evaluate the intensity of particular farm units based on the technologies and practices used by the farmer, and the degree to which they are used.This revised version was published online in November 2005 with corrections to the Cover Date.     

新疆焉耆县农村人居环境整治情况及满意度分析

农村人居环境整治作为实施乡村振兴战略的重要抓手 ,是建设美丽乡村的关键环节。通过对焉耆县农村人居环境整治示范村整治情况的分析,发现村民对人居环境的总体满意度较高,但部分村庄基础设施仍存在短板,道路、亮化等基础设施还需要进一步规范,厕所、自来水等改建设施利用率有待提高,村民人居环境认知存在不足,主动参与家园建设的意识还不够强。     

黄土高原坡地林草复合系统景观边界植物多样性特征

以黄土高原坡地刺槐林—草地复合系统景观边界为研究对象,按一定的生态梯度调查分析了边界植物种的分布特点。结果表明,草地、林地斑块内都有自身的植物种类分布;草地斑块内有较高的植物多样性。在草地斑块内,距林缘8~16m区域为边界植物多样性边缘效应的显著区;林地斑块内β多样性变化剧烈,林缘处的群落相异系数(CD)、Cody指数都最大,共有度指数(CP)最小,CD、Cody与CP成反比。     

作物同异育种智能决策系统的研制及其在小麦育种中的应用

为促进作物定量化育种进程,以作物育种同异理论为蓝本,以Eclipse为开发环境,以Excel代替数据库,研制出作物同异育种智能决策系统。结果表明,该系统界面友好、美观,操作方便、快捷,便于推广应用,具有其他集成开发环境(IDE)软件所不具有的较强灵活性和可扩展性。应用实例表明,该系统对于小麦育种有一定的指导作用。     

Efficient management of transportation logistics related to animal disease outbreaks

Vehicle routing is a key instrument to manage and control animal disease outbreaks. This paper focuses on an efficient, user-friendly and automatic procedure to manage transportation logistics to and between farms in the case of an outbreak. This procedure can be embedded into a veterinary geographical information system for the management and control of disease outbreaks. The transportation logistics for the problem at hand can be divided into two main transportation categories: (i) round itineraries, which are special cases of the travelling salesman problem, and (ii) one-to-one itineraries. Attention is given to the use of user-friendly, heuristic yet efficient algorithms for the determination of these itineraries. It is furthermore shown that the procedure is developed in such a way that the identified routes meet both national and international regulations in force during disease outbreaks.     

Linking water market functioning, access to water resources and farm production strategies: example from Pakistan

As a response to inadequacy in canal water supplies, farmers in Pakistan have invested in private tubewells to control irrigation water resources. Also, they participate in surface water and groundwater markets that take place within tertiary units of the irrigation system.The present paper describes the functioning and organization of these water markets, using information collected in sample watercourses of the Fordwah Branch irrigation system, South-Punjab, Pakistan. The variability in type and intensity of water markets is investigated with regard to access to water resources and farm production strategies and constraints.     

燃油温度和喷射压力对葵花籽油与柴油喷雾特性的影响

为探究纯植物油作为压燃内燃机替代燃料的雾化问题,利用纹影法对葵花籽纯植物油和普通柴油在不同试验条件下的喷雾特性进行了对比研究,分析了燃油温度和喷射压力对2种燃料喷雾贯穿距、喷雾锥角和空气卷吸作用的影响。研究结果表明:葵花籽油的喷雾贯穿距和喷雾锥角均随着喷射压力和燃油温度的升高而增大,与柴油的变化规律相似。温度从60℃升高到90℃,喷油压力为60 MPa时喷雾贯穿距和喷雾锥角的平均增幅分别为12.4%和9.6%,120 MPa时分别为5%和4.14%;喷油压力从60 MPa升高到120 MPa,温度为60℃时喷雾贯穿距和喷雾锥角的平均增幅分别为39.7%和16.7%,90℃时分别为30.6%和10.9%;当喷射压力、背景压力和燃油温度相同时,葵花籽油比柴油具有更大的贯穿距和更小的喷雾锥角,且喷雾贯穿距平均增幅为22.5%,喷雾锥角平均降幅为60.3%;升高燃油温度和升高喷射压力都会增强雾注的空气卷吸作用,但葵花籽油的空气卷吸作用要明显弱于普通柴油。研究结果可为纯植物油作为内燃机替代燃料的可行性研究提供参考。