404 research outputs found
Alternative Insurance Indexes for Drought Risk in Developing Countries
The paper compares the risk coping potential of insurances that are based on indices derived from weather (rainfall and temperature) data as well as from crop model and remote sensing analyses. Corresponding indices were computed for the case of wheat production in the Aleppo region of northern Syria, representative for agricultural production systems in many developing countries. The results demonstrate that weather derivatives such as the rainfall sum index (RSI) and the rainfall deficit index (RDI) have a very good potential for coping with risk in semiarid areas. Crop simulation model index (CSI) on the other hand could serve as an alternative to RSI and RDI when historical farm yield data is not available or not reliable. In such cases we simulated historical yields using the CropSyst cropping system simulation model. Remote sensing data could be used to establish index insurances where weather stations are sparsely located and (daily time step) weather data thus not available. The study analyzes two indexes estimated from the Normalized Differential Vegetation Index (NDVI): (1.) the farm level NDVI (FNDVI) and (2.) the area level NDVI (ANDVI). FNDVI may have a very high potential for securing farm revenues, but may be prone to moral hazard since farm management changes and subsequent gains or losses in crop production are directly revealed by the NDVI when high resolution images are used. Therefore, we recommend ANDVI for developing countries since the index is estimated for the whole agricultural zone similar to traditional area-yield insurances.risk management, index insurance, alternative index, CropSyst, NDVI, Risk and Uncertainty,
Non-perturbative renormalization of the axial current with improved Wilson quarks
We present a new normalization condition for the axial current, which is
derived from the PCAC relation with non-vanishing mass.
Using this condition reduces the O(r_0 m) corrections to the axial current
normalization constant Z_A for an easier chiral extrapolation in the cases,
where simulations at zero quark-mass are not possible. The method described
here also serves as a preparation for a determination of Z_A in the full
two-flavor theory.Comment: 3 pages, 3 figures, Lattice2003(improve
East Africa Soil Carbon Workshop: Science to inform policy
Introduction and rationale:
Global soils contain about 2344 billion tons of organic carbon. This is the largest terrestrial pool of organic carbon. Small changes in soil organic carbon (SOC) stocks could result in significant impacts on the global carbon balance. Trapping carbon in the soil contributes to reducing greenhouse gas (GHG) emissions from agriculture. Managing our soils better can also help us to adapt to a changing climate by improving soil health, soil productivity (and crop yields) and agro-ecosystem resilience. However, not all soils are the same.
Geography, climate, and land use play a crucial role in how much carbon soils can potentially absorb, or how much they lose. While expectations are high â especially for degraded soils of sub-Saharan Africa â that soils can play crucial role in mitigating climate change, details on the where, how, and potential costs are missing.
The East Africa Soil Carbon Workshop â Science to Inform Policy brought together 28 participants from 11 countries: Ethiopia, Kenya, Uganda, Rwanda, Tanzania, South Africa, Madagascar, Germany, France, Netherlands, and Sweden (10 women and 18 men). Participants included decision makers, practitioners and implementers, and researchers in the fields of biophysical and social science. The aim was to exchange state-of-the art knowledge; review and discuss latest methods, metrics and tools for assessing SOC and mapping & monitoring SOC dynamic hotspots; and to discuss entry points for shaping gender-sensitive policies towards a green economy where carbon sequestration in soils is a recognized component. During group work sessions, the participants discussed and developed key messages that are relevant for policymaking on SOC sequestration in East Africa and beyond. This report summarizes contributions from participants, lessons learnt and action points
Soil health and ecosystem services: Lessons from sub-Sahara Africa (SSA)
Management practices to improve soil health influence several ecosystem services including regulation of water
flows, changes in soil biodiversity and greenhouse gases that are important at local, regional and global levels.
Unfortunately, the primary focus in soil health management over the years has been increasing crop productivity
and to some extent the associated economics and use efficiencies of inputs. There are now efforts to study the
inter-relationship of associated ecosystem effects of soil health management considering that sustainable intensification
cannot occur without conscious recognition of these associated non-provisioning ecosystem services.
This review documents the current knowledge of ecosystem services for key management practices based
on experiences from agricultural lands in sub-Sahara Africa (SSA). Here, practicing conservation agriculture
(CA) and Integrated Soil fertility management (ISFM) have overall positive benefits on increasing infiltration
(> 44), reducing runoff (> 30%) and soil erosion (> 33%) and increases soil biodiversity. While ISFM and
Agroforestry increase provisioning of fuelwood, fodder and food, the effect of CA on the provisioning of food is
unclear. Also, considering long-term perspectives, none of the studied soil health promoting practices are increasing
soil organic carbon (SOC). Annual contributions to greenhouse gases are generally low (< 3 kg N2O
haâ1) with few exceptions. Nitrogen leaching vary widely, from 0.2 to over 200 kg N haâ1 and are sometimes
inconsistent with N inputs. This summary of key considerations for evaluating practices from multiple perspectives
including provisioning, regulating, supporting and cultural ecosystem services is important to inform
future soil health policy and research initiatives in SSA
Long-term productivity and sustainability of crop-livestock systems through integrated soil fertility management
Productivity in Crop-Livestock Systems can be maximized using Integrated Soil Fertility Management (ISFM). ISFM combines (i) improved germplasm (ii) mineral fertilizer application (iii) organic matter management and (v) adapted agronomy. CIAT established a long-term trial in Western Kenya in the village of Murumba Yiro in 2003 to assess ISFM technologies
Running quark mass in two flavor QCD
We present first results for the step scaling function sigma_P of the
renormalization factor Z_P of the pseudoscalar density. The simulations are
performed within the framework of the Schroedinger functional with two flavors
of O(a) improved Wilson fermions. The knowledge of sigma_P is required to
compute the renormalization group invariant quark masses. We also study the
performance of a variant of the HMC algorithm using two pseudofermion fields.Comment: 3 pages, 2 figures, Lattice2002(spectrum
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