Gender responsive communication tools and approaches for scaling the Triple S Technology in Ethiopia and Ghana

The RTB Triple S Scaling project (3S+) is a 27-month project funded by the CGIAR Research Program on Roots, Tubers and Bananas (RTB) and was operational in Ghana and Ethiopia. The aim of the project was to scale out the Triple S technology – a root-based vine production technology suitable for arid and semi-arid areas. Amongst the scaling strategies developed and implemented, was an outreach strategy based on three types of treatment: Core communities, informed communities, spillover communities. Subsequently, various communication tools and approaches were used for the three types of communities. Following use of these strategies, there was a need to assess their effectiveness in aiding technology dissemination, uptake and scaling. A study was designed to assess which communication methods were best suited to the needs of women and men in transmission and delivery of the Triple S innovation scaling package

Striga hermonthica seed bank dynamics: process quantification and modelling

Key words: Weed control, integrated management, parasitic weed, population, sorghum, millet. This thesis presents a study on the quantification of seed bank dynamics of the parasitic weed Striga hermonthica. The main objectives were to quantify transition rates between different stages of the life cycle, determine these under different conditions and control strategies and to develop and use a population model to project long-term seed bank dynamics. To this end, field experiments were performed in Mali, with sorghum in 2002, 2003 and 2004, and Niger, with millet in 2004. Three demographic processes behind Striga hermonthica seed bank replenishment were determined and quantified, namely (1) recruitment of Striga plants, (2) survival of emerged Striga plants to maturity and (3) fecundity (number of seeds produced per mature plant). Striga seed production was highly variable between years and sites, because of high variability in recruitment. Different control strategies reduced Striga at different stages in the life cycle. Intercropping the host cereal with non-host trap crops mainly reduced recruitment and survival while late weeding acted almost solely on survival to maturity. A critical re-assessment of the seed bag method used to determine Striga seed mortality in the soil, led to the conclusion that the method overestimates seed mortality. It was suggested to adapt the seed bag method in order to measure seed mortality more accurately. An adapted seed bag burial method and a soil sampling method were used simultaneously to determine processes and rates of seed bank depletion under bare soil, fallow and different crop covers. Results suggested that the main cause of seed bank depletion was germination of seeds. Both methods yielded similar seed bank depletion percentages and most germination was found in soil under host crops, sorghum and millet, followed by intercrops of a host and a non-host trap crop, non-host crops, fallow and bare soil. The information and insights obtained were used to develop a spatially explicit, stochastic Striga population model, with which long-term effects of crop systems and control was modelled. The spatial patterns of emerged Striga plants after point inoculation with stochasticity in the attachment stage of Striga resembled spatial distribution of Striga that is typically observed in farmers’ fields. Sensitivity analysis showed that only two slope parameters for the dispersal curve of seeds and seed death other than germination in response to millet roots were of minor importance for population growth. The model indicated that intercrops of host cereals and non-host crops showed higher potential to reduce the Striga seed bank than did rotations of these. The implications of the findings are discussed in the context of integrated Striga management and participatory research

Striga hermonthica seed bank dynamics: process quantification and modelling

Key words: Weed control, integrated management, parasitic weed, population, sorghum, millet. This thesis presents a study on the quantification of seed bank dynamics of the parasitic weed Striga hermonthica. The main objectives were to quantify transition rates between different stages of the life cycle, determine these under different conditions and control strategies and to develop and use a population model to project long-term seed bank dynamics. To this end, field experiments were performed in Mali, with sorghum in 2002, 2003 and 2004, and Niger, with millet in 2004. Three demographic processes behind Striga hermonthica seed bank replenishment were determined and quantified, namely (1) recruitment of Striga plants, (2) survival of emerged Striga plants to maturity and (3) fecundity (number of seeds produced per mature plant). Striga seed production was highly variable between years and sites, because of high variability in recruitment. Different control strategies reduced Striga at different stages in the life cycle. Intercropping the host cereal with non-host trap crops mainly reduced recruitment and survival while late weeding acted almost solely on survival to maturity. A critical re-assessment of the seed bag method used to determine Striga seed mortality in the soil, led to the conclusion that the method overestimates seed mortality. It was suggested to adapt the seed bag method in order to measure seed mortality more accurately. An adapted seed bag burial method and a soil sampling method were used simultaneously to determine processes and rates of seed bank depletion under bare soil, fallow and different crop covers. Results suggested that the main cause of seed bank depletion was germination of seeds. Both methods yielded similar seed bank depletion percentages and most germination was found in soil under host crops, sorghum and millet, followed by intercrops of a host and a non-host trap crop, non-host crops, fallow and bare soil. The information and insights obtained were used to develop a spatially explicit, stochastic Striga population model, with which long-term effects of crop systems and control was modelled. The spatial patterns of emerged Striga plants after point inoculation with stochasticity in the attachment stage of Striga resembled spatial distribution of Striga that is typically observed in farmers’ fields. Sensitivity analysis showed that only two slope parameters for the dispersal curve of seeds and seed death other than germination in response to millet roots were of minor importance for population growth. The model indicated that intercrops of host cereals and non-host crops showed higher potential to reduce the Striga seed bank than did rotations of these. The implications of the findings are discussed in the context of integrated Striga management and participatory research

Changes in the sensitivity of parasitic weed seeds to germination stimulants

The effects of preconditioning temperature and preconditioning period on the sensitivity of parasitic weed seeds to the synthetic germination stimulant GR24 were studied under laboratory and field conditions. The temperature during preconditioning of Orobanche cumana and Striga hermonthica seeds strongly affected the responsiveness of the seeds to the applied germination stimulant. Preconditioning at an optimal temperature (21degreesC for O. cumana and 30degreesC for S. hermonthica) rapidly released dormancy and increased the sensitivity to GR24 by several orders of magnitude. After reaching maximum sensitivity, prolonged preconditioning rapidly induced secondary dormancy, i.e. decreased sensitivity of O. cumana and S. hermonthica to GR24. The rapid change in sensitivity of preconditioned seeds to germination stimulants during prolonged preconditioning was particularly visible at low concentrations of GR24. GR24 at higher concentrations (0.1 and 1 mg l(-1)) usually induced high germination of both species, regardless of the preconditioning period. The striking similarities between the response of parasitic weed seeds to GR24, described here, and results in the literature on non-parasitic wild plant seeds are discussed. Our results show that parasitic weed seeds are highly sensitive to the germination stimulant for a short period of time only, and then enter into secondary dormancy relatively quickly. The similar germination pattern of S. hermonthica seeds preconditioned for prolonged periods of time under laboratory and field conditions suggests that the mechanism observed is of ecological significance

Albatross : multi-agent rule based model of activity pattern decisions

The development of ALBATROSS: A Learning-Based, Transportation-Oriented Simulation System is summarized. This activity-based model of activity-travel behavior is derived from theories of choice heuristics that consumers apply when making decisions in complex environments. The model, one of the most comprehensive of its kind, predicts which activities are conducted when, where, for how long, and with whom, and the transport mode involved. In addition, various logical, temporal, spatial, spatial-temporal, and institutional constraints are incorporated in the model. The conceptual underpinnings of the model, its architecture, the functionality of its key agents, data collection, and model performance are discussed