R package gdistance: Distances and routes on geographical grids

The R package gdistance provides classes and functions to calculate various distance measures and routes in heterogeneous geographic spaces represented as grids. Least-cost distances as well as more complex distances based on (constrained) random walks can be calculated. Also the corresponding routes or probabilities of passing each cell can be determined. The package implements classes to store the data about the probability or cost of transitioning from one cell to another on a grid in a memory-efficient sparse format. These classes make it possible to manipulate the values of cell-to-cell movement directly, which offers flexibility and the possibility to use asymmetric values. The novel distances implemented in the package are used in geographical genetics (applying circuit theory), but also have applications in other fields of geospatial analysis

Changes in farmers' knowledge of maize diversity in highland Guatemala, 1927/37-2004

Small-scale studies on long-term change in agricultural knowledge might uncover insights with broader, regional implications. This article evaluates change in farmer knowledge about crop genetic resources in highland Guatemala between 1927/37 and 2004. It concentrates on maize (Zea mays ssp. mays L.) in one Guatemalan township, Jacaltenango, an area with much ecological and maize diversity. It relies on a particular type of baseline information: lists of farmer-defined cultivars drawn up by ethnographers in the first half of the twentieth century. A questionnaire format based on two independent lists of local farmer cultivars dating from 1927 and 1937 was used to assess changes in maize diversity. Comparisons between attributes given to each cultivar in the past and in 2004 were used as a partial test of the stability of cultivar identity. In farmers' perceptions, cultivar loss was low and limited to certain cultivars adapted to the warmer environments. Crop production problems were mentioned as the main motives for change. No evidence for a loss of cultivars due to the political violence of the 1980s was found. In the lower areas many newly introduced cultivars were found, which reportedly provide solutions for the production problems the older cultivars have. The article contrasts these findings with those of an earlier study which suggested much cultivar loss due to political violence, and draws conclusions about the methodological implications

Adaptacion climatica mediante ensayos en finca: Evaluacion Participativa Masiva (EPM). Guia metodologica

La Evaluacion Participativa Masiva (EPM) es un nuevo enfoque para evaluar variedades y otras tecnologias agricolas en finca, bajo condiciones representativas. A traves de un proceso de experimentacion sencillo y practico, los agricultores identifican innovaciones que les benefician realmente. EPM es una metodologia completa que sirve tanto para la investigacion como para la distribucion de variedades y otras tecnologias agricolas en areas con condiciones variables. A traves de un esquema de pruebas distribuidas geograficamente, la metodología EPM puede proveer informacion sobre los patrones geograficos en la adaptacion climatica y ayudar a acelerar la identificacion de tecnologias apropiadas localmente para responder al cambio climatico. Provee una forma de conectar el desarrollo de nuevas tecnologias realizado por institutos de investigacion con las experiencias de los agricultores. El proceso de EMP es apoyado por una plataforma digital que se encuentra en www.climmob.net. Esta publicacion provee una descripcion de la metodología con lineamientos para su uso en el campo

Farmer experimentation for climate adaptation with triadic comparisons of technologies (tricot): a methodological guide

Triadic Comparisons of Technologies (tricot), is a new approach to test crop varieties and other technologies on-farm, under realistic conditions. Through simple and hands-on experimentation, the participating farmers identify innovations that will be of real benefit to them. Tricot is a ready-made methodology, serving both research, and the dissemination of varieties and other technologies and practices in highly variable areas. Through geographically distributed testing, tricot is able to provide information about geographic patterns in climate adaptation and help to speed up the identification of locally suitable technologies to respond to climate change. It provides a means to linktechnology development of research institutes to real-life experiences of farmers. It is supported by a digital platform that can be found at www.climmob.net. This publication provides a description of the methodology with guidelines for its implementation in the field

gamification of farmer participatory priority setting in plant breeding design and validation of agroduos

ABSTRACTParticipatory methods to characterize farmers' needs and preferences play an important role in plant breeding to ensure that new varieties fulfill the needs and expectations of end users. Different farmer-participatory methods for priority setting exist, each one responding differently to trade-offs between various requirements, such as replicability, simplicity, or granularity of the results. All available methods, however, require training, academic skill, and staff time of specially qualified professionals. Breeding and variety replacement may be accelerated by empowering non-academic organizations, such as NGOs and farmer organizations, to carry out farmer-participatory priority setting. But for this use context, currently no suitable method is available. A new method is needed that demands relatively low skill levels from enumerators and respondents, engages farmers without the need for extrinsic incentives, and gives statistically robust results. To achieve these objectives, we followed prin..

Modelling rankings in R: the PlackettLuce package

This paper presents the R package PlackettLuce, which implements a generalization of the Plackett-Luce model for rankings data. The generalization accommodates both ties (of arbitrary order) and partial rankings (complete rankings of subsets of items). By default, the implementation adds a set of pseudo-comparisons with a hypothetical item, ensuring that the underlying network of wins and losses between items is always strongly connected. In this way, the worth of each item always has a finite maximum likelihood estimate, with finite standard error. The use of pseudo-comparisons also has a regularization effect, shrinking the estimated parameters towards equal item worth. In addition to standard methods for model summary, PlackettLuce provides a method to compute quasi standard errors for the item parameters. This provides the basis for comparison intervals that do not change with the choice of identifiability constraint placed on the item parameters. Finally, the package provides a method for model-based partitioning using covariates whose values vary between rankings, enabling the identification of subgroups of judges or settings that have different item worths. The features of the package are demonstrated through application to classic and novel data sets.Comment: In v2: review of software implementing alternative models to Plackett-Luce; comparison of algorithms provided by the PlackettLuce package; further examples of rankings where the underlying win-loss network is not strongly connected. In addition, general editing to improve organisation and clarity. In v3: corrected headings Table 4, minor edit

Evaluación de la efectividad de los métodos participativos en estimar vulnerabilidad al cambio climático en Colombia

La mayoría de los esfuerzos para ayudar a las sociedades a adaptarse al cambio climático se han centrado en enfoques impuestos desde el gobierno hacia la comunidad, sin tener en cuenta los factores locales como modos de vida, ubicación geográfica, riesgos climáticos y características socioeconómicas. La adaptación de base comunitaria, pretende que con base al conocimiento y la experiencia local se generen estrategias de adaptación al cambio climático (comunidad- gobierno). La obtención de ese conocimiento por parte de los investigadores, se hace generalmente a través de encuestas y más recientemente por medio de metodologías participativas, que se aplican en talleres. Sin embargo, la eficacia de estas metodólogas en obtener información clave para generar planes de adaptación al cambio climático ha sido poco evaluada. Por esto Bioversity International y Fundación Conserva evalúan la eficacia de estas metodologías, agrupadas en un kit de herramientas, y comparan los resultados con los obtenidos a través de la encuesta línea base a nivel de hogar de CCAFS. Los resultados sugieren que el kit recopila información clave que permite generar planes de adaptación al cambio climático, aunque comparándolo con otros kits usados para el mismo fin, podría ser mejorado. Se sugiere incluir la forma de recopilación y análisis de la información, omitir actividades que colectan información repetitiva y ajustar la duración de las actividades del kit, para que se acomoden a las actividades rurales. Tanto, la encuesta como las metodologías participativas permiten la recopilación de información valiosa y complementaria. La encuesta requiere de menos tiempo para realizarse y no depende de la asistencia de las personas a los talleres. También, facilita la recolección de información personal y a nivel de cada hogar y permite la entrada a las viviendas para tener una idea de las condiciones de vida. Por otro lado, no facilita la obtención de información que requiera discusión y análisis de situaciones colectivas y que se abordan mejor de manera participativa. Además, las metodologías participativas promueven la interacción entre participantes e investigadores lo que facilita identificar miembros claves de la comunidad

Step-wise guide for weighing cocoa

This is a short guide to teach weighing cocoa with a conventional scale, used in Ghana

How can the Data Revolution contribute to climate action in smallholder agriculture?

In this article, we discuss the ongoing Data Revolution in relation to climate action in agriculture. Data are highly relevant for climate action, as climate change makes current local knowledge increasingly irrelevant and requires smarter management of agricultural systems. We discuss five datarelated concepts and explore how they are linked with agricultural climate action: lean data, crowdsourcing, big data, ubiquitous computing, and information design. We show practical examples for each of these concepts. There are many opportunities for improving agricultural development projects, providing new services to smallholder farmers, and generating better information for policy- and decision-making. Making the Data Revolution work for smallholder farmers’ climate action not only takes further technological development, but also requires careful governance and public investment to avoid a few actors taking over the current innovation space and stifle further development