Digital soil mapping in the Bara district of Nepal using kriging tool in ArcGIS

Digital soil mapping has been widely used to develop statistical models of the relationships between environmental variables and soil attributes. This study aimed at determining and mapping the spatial distribution of the variability in soil chemical properties of the agricultural floodplain lands of the Bara district in Nepal. The study was carried out in 23 Village Development Committees with 12,516 ha total area, in the southern part of the Bara district. A total of 109 surface soil samples (0 to 15 cm depth) were collected and analyzed for pH, organic matter (OM), nitrogen (N), phosphorus (P, expressed as P2O5), potassium (K, expressed as K2O), zinc (Zn), and boron (B) status. Descriptive statistics showed that most of the measured soil chemical variables (other than pH and P2O5) were skewed and nonnormally distributed and logarithmic transformation was then applied. A geostatistical tool, kriging, was used in ArcGIS to interpolate measured values for those variables and several digital map layers were developed based on each soil chemical property. Geostatistical interpolation identified a moderate spatial variability for pH, OM, N, P2O5, and a weak spatial variability for K2O, Zn, and B, depending upon the use of amendments, fertilizing methods, and tillage, along with the inherent characteristics of each variable. Exponential (pH, OM, N, and Zn), Spherical (K2O and B), and Gaussian (P2O5) models were fitted to the semivariograms of the soil variables. These maps allow farmers to assess existing farm soils, thus allowing them to make easier and more efficient management decisions and maintain the sustainability of productivity

Spatial variability in soil pH and land use as the main influential factor in the red beds of the Nanxiong Basin, China

Soil pH is the main factor affecting soil nutrient availability and chemical substances in soil. It is of great significance to study the spatial variability of soil pH for the management of soil nutrients and the prediction of soil pollution. In order to explore the causes of spatial variability in soil pH in red-bed areas, the Nanxiong Basin in south China was selected as an example, and soil pH was measured in the topsoil by nested sampling (0–20 cm depth). The spatial variability characteristics of soil pH were analyzed by geostatistics and classical statistical methods, and the main factors influencing spatial variability in soil pH are discussed. The coefficient of variation in the red-bed areas of Nanxiong Basin was 17.18%, indicating moderate variability. Geostatistical analysis showed that the spherical model is the optimal theoretical model for explaining variability in soil pH, which is influenced by both structural and random factors. Analysis of the spatial distribution and pattern showed that soil pH is relatively high in the northeast and southwest, and is lower in the northwest. These results indicate that land use patterns and topographic factors are the main and secondary influencing factors, respectively

Cores and Peripheries: Spatial Analysis of HCV Voucher Distribution in the San Francisco

The Housing Choice Voucher (HCV) program is touted as a mechanism for providing low income households with mobility, and through that mobility, access to higher opportunity neighborhoods (HUD, 2006; McClure, 2014; Winnick, 1995). However, the success of the voucher program requires an existing supply of available housing units with landlords who are willing to participate in the program. Tight housing markets, where households are most in need of rent subsidies, are typically also the most difficult markets to find available units and willing landlords, resulting in limited choices for HCV households (Basolo and Nguyen, 2005; Khadduri, 2005). In these conditions, we can expect to find that voucher holders behave like other housing seekers and search out locations where they can maximize their housing dollars in terms of both unit characteristics and locational amenities

Resilience in Soils and Land Use

Currently, studies on land use in territorial planning are of interest, the purpose of which was previously to analyze the aptitude of each type of land for a specific use, based on its ability to assume impacts and the potential that the land may have had. The analysis of erosive risks constitutes a parameter to take into account in said management.The scientific community, given the enormous social interest in monitoring and controlling the environment, is developing methodologies that allow such control that is more efficient. One of the environmental factors to consider is the soil, which constitutes the support for life and is one of the basic natural elements, which is evident in the European Soil Charter, of the Council of Europe, which says, in its first point: “The soil is one of the most precious goods of Humanity. It allows the life of plants, animals and man on the surface of the Earth”. This European charter also highlights the scarcity and fragility of the edaphic resource, indicating that it must be protected through a greater effort in scientific research and interdisciplinary collaboration to ensure the rational use and conservation of soil

Remote Sensing and Site Specific Crop Management in Precision Agriculture

Application of variable crop inputs in the right quantity and place is very important for optimizing plant growth and final yield through efficient use of finite resources and minimum environmental impacts. In this framework, actions were carried out to support the adoption of PA: In Chapter 1 several remotely sensed vegetation indices (VIs) were used to estimate the spatial crop yields of winter cereals (durum and bread wheat) and spring dicots (sunflower and coriander) through simple correlation over five years. Pixel level study was also investigated between original VIs data and kriged crop yield data. Results showed that spatial variability of crops can be effectively assessed through Landsat imagery with 30 m resolution even on a relatively small area (11.07 ha). Simple ratio and normalized difference vegetation index were shown slightly better indices during vegetative to reproductive stages as compared to enhanced vegetation index, soil adjusted vegetation index, green normalized difference vegetation index and green chlorophyll index. Pixel level study also demonstrated a good agreement between five classes of VIs and grain yield. In Chapter 2, three yield stability classes (YSCs) were developed using spatio-temporal yield maps over five years: high yielding and stable (HYS), low yielding and stable (LYS), and unstable class. Thereafter, we evaluated the YSCs through simple correlations and statistical differences of soil data with spatiotemporal yield within YSCs. Results showed that spatial maps were more consistent with the YSCs map than the temporal stability map. Yield classes were found considerably consistent with soil properties. Lower values of soil apparent electrical conductivity (ECa), in the average, were consistent with HYS class featuring maximum crop yield (122 %), compared to LYS and unstable class. In addition, the balance between precipitation and evapo-transpiration support the fluctuations of yield across years in the unstable area

Irrigation and drainage in the new millennium

Presented at the 2000 USCID international conference, Challenges facing irrigation and drainage in the new millennium on June 20-24 in Fort Collins, Colorado.Irrigation scheduling has been promoted as management tool to minimize irrigation water application, however, few irrigators regularly followed any rigorous scheduling methodology. Kansas State University Research and Extension in conjunction with an irrigation association, Water PACK, began a long-term project to promote ET based irrigation scheduling and other management technology. Area irrigators serve as the focal point of the project and over time have been asked to assume responsibility of scheduling the project fields. A long-term commitment and on-farm activities such as variable water application tests and center pivot uniformity tests seems to have generated confidence and acceptance of ET-based irrigation scheduling

2000 USCID international conference

Presented at the 2000 USCID international conference, Challenges facing irrigation and drainage in the new millennium on June 20-24 in Fort Collins, Colorado.Includes bibliographical references.Sponsored by U.S. Committee on Irrigation and Drainage.Multicriteria strategic planning for rehabilitation of the Wind River Irrigation Project, Wyoming -- Environmental management plan for the Irrigation Improvement Project (IIP) - Tajan Subproject -- Organizational requisites of successful irrigation system rehabilitation: cases from Nepal -- Verification-based planning for modernizing irrigation systems -- Policy reforms for sustainable irrigation management in Indonesia -- Bench terracing - a cost effective alternative to traditional irrigation in the Philippines -- GIS-based management system for irrigation districts -- Capacity building for the practice of irrigated agriculture -- Planning of modern irrigation systems integrated with human settlement for enhanced reuse of water -- Drainage in the Aral Sea Basin: past and future -- Impacts and solutions to urbanization on agricultural water resources -- Improving subsurface drainage design and management to reduce salt loads from irrigation areas in southeastern Australia -- Evaluation and update of drainage water management options on the westside San Joaquin Valley, California -- Simulation studies on use of saline water for irrigation in a semi-arid environment -- Hydrodynamic modeling to optimize irrigation efficiency -- Planning to meet future water needs -- Tracing the history of the development and management of two irrigations systems in the Terai of Nepal -- Secondary water supply management for irrigation districts and canal companies -- Role of canal automation and farmer's participation in managing water scarcity: a case study from Orissa, India -- PIM: a reality in Asia? -- Private group irrigation projects in Manitoba: Central Manitoba Resource Management Ltd. - a case study -- Evaluation of dielectric soil moisture sensors for irrigation scheduling on farms -- Sensitivity of micro irrigation emitters to plugging using treated municipal wastewaters -- NCWCD irrigation scheduling program - converting to a web-based accessible program -- On-farm activities to promote irrigation scheduling - the South Kansas Irrigation Management Project

Irrigation and drainage in the new millennium

Presented at the 2000 USCID international conference, Challenges facing irrigation and drainage in the new millennium on June 20-24 in Fort Collins, Colorado.Includes bibliographical references.In 1998, eight irrigation districts in the Lower Rio Grande Valley of Texas initiated efforts to develop GIS-based District Management Systems (DMS). This paper provides a description of GIS (geographical information system) as applied to irrigation districts, its potential for improving the day-to-day management of districts, and the progress and difficulties encountered by the 8 districts in GIS mapping and implementation. Examples of how districts are using GIS are given, along with the value and use of the DMS in a regional water planning project

Water Resources Management Models for Policy Assessment

This book is a compilation of original research articles that apply a variety of techniques to identify and evaluate water resource management policies. These papers cover a wide range of topics and methodologies applied across the world, from a local to a continental scope. They illustrate open challenges in water resource management, such as the quantitative assessment of policy impacts, trade-off analyses, understanding the water–energy–food–environment nexus, collaborative model development, stakeholder engagement, formalizing social interactions, or improving the theoretical understanding of complex adaptive systems. Therefore, this book is a representation of research areas that have emerged from the origins of water resource systems analysis, seeking to improve the way in which water policy is formulated and implemented