Water and the Rural Poor: Interventions for Improving Livelihoods in Sub-Saharan Africa

The Food and Agriculture Organization of the United Nations and the International Fund for Agricultural development collaborated on this report on water and rural poverty in sub-Saharan Africa. The paper addresses the potential benefits of water initiatives under a livelihood approach, with special consideration to two major recommendations: that investments in water infrastructure must act in concert with political, institutional, market and other related concerns; and that interventions must be context-specific, given the vast heterogeneity in water use and needs among sub-Saharan African rural poor

Groundwater use for irrigation - a global inventory

Irrigation is the most important water use sector accounting for about 70% of the global freshwater withdrawals and 90% of consumptive water uses. While the extent of irrigation and related water uses are reported in statistical databases or estimated by model simulations, information on the source of irrigation water is scarce and very scattered. Here we present a new global inventory on the extent of areas irrigated with groundwater, surface water or non-conventional sources, and we determine the related consumptive water uses. The inventory provides data for 15 038 national and sub-national administrative units. Irrigated area was provided by census-based statistics from international and national organizations. A global model was then applied to simulate consumptive water uses for irrigation by water source. Globally, area equipped for irrigation is currently about 301 million ha of which 38% are equipped for irrigation with groundwater. Total consumptive groundwater use for irrigation is estimated as 545 km3 yr−1, or 43% of the total consumptive irrigation water use of 1 277 km3 yr−1. The countries with the largest extent of areas equipped for irrigation with groundwater, in absolute terms, are India (39 million ha), China (19 million ha) and the United States of America (17 million ha). Groundwater use in irrigation is increasing both in absolute terms and in percentage of total irrigation, leading in places to concentrations of users exploiting groundwater storage at rates above groundwater recharge. Despite the uncertainties associated with statistical data available to track patterns and growth of groundwater use for irrigation, the inventory presented here is a major step towards a more informed assessment of agricultural water use and its consequences for the global water cycle

Development and validation of the global map of irrigation areas

A new version of a digital global map of irrigation areas was developed by combining irrigation statistics for 10 825 sub-national statistical units and geo-spatial information on the location and extent of irrigation schemes. The map shows the percentage of each 5 arc minute by 5 arc minute cell that was equipped for irrigation around the year 2000. It is thus an important data set for global studies related to water and land use. This paper describes the data set and the mapping methodology and gives, for the first time, an estimate of the map quality at the scale of countries, world regions and the globe. Two indicators of map quality were developed for this purpose, and the map was compared to irrigated areas as derived from two remote sensing based global land cover inventories

Cell cycle progression is associated with distinct patterns of phosphorylation of Op18

Op18 is a highly conserved major cytosolic phosphoprotein which has been implicated in signal transduction in a wide variety of cell types. Freshly isolated peripheral blood lymphocytes (PBL) constitutively express low levels of mostly unphosphorylated Op18. Following mitogenic stimulation of PBL, Op18 synthesis is induced at a time when cells are entering S-phase. In this study we have characterized Op18 phosphorylation during progression of freshly isolated PBL through the cell cycle. Transition from G0 to G1 following activation with OKT3 was associated with an increase in a phosphorylated form designated Op18c. Progression of cells through G1 into S resulted in an increase in phosphorylated Op18 forms, designated Op18a and Op18b, which paralleled new Op18 synthesis. Transition of cells into G2+M resulted in the appearance of the more acidic phosphorylated forms Op18d and Op18e. Calphostin C, a specific inhibitor of protein kinase C, dramatically decreased all forms of phosphorylated Op18 in OKT3 treated Jurkat cells. Our results suggest that Op18 phosphorylation is mediated in part by PKC activation as well as by other kinases yielding different phosphorylated forms at specific stages of the cell cycle.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/30037/1/0000405.pd

Revitalizing Asia's irrigation: to sustainably meet tomorrow's food needs

Irrigated farming / Food security / Irrigation management / Participatory management / Water users associations / Public sector / Private sector / Farmer managed irrigation systems / Surface irrigation / Pumps / Groundwater irrigation / Water productivity / Models / Reservoirs / Canals / Tanks / Irrigation programs / Climate change / Water conservation / Asia

African farmer-led irrigation development: re-framing agricultural policy and investment?

The past decade has witnessed an intensifying focus on the development of irrigation in sub-Saharan Africa. It follows a 20-year hiatus in the wake of disappointing irrigation performance during the 1970s and 1980s. Persistent low productivity in African agriculture and vulnerability of African food supplies to increasing instability in international commodity markets are driving pan-African agricultural investment initiatives, such as the Comprehensive Africa Agricultural Development Programme (CAADP), that identify as a priority the improvement in reliability of water control for agriculture. The paper argues that, for such initiatives to be effective, there needs to be a re-appraisal of current dynamics of irrigation development in sub-Saharan Africa, particularly with respect to the role of small-scale producers’ initiatives in expanding irrigation. The paper reviews the principal forms such initiatives take and argues that official narratives and statistics on African irrigation often underestimate the extent of such activities. The paper identifies five key characteristics which, it argues, contradict widely held assumptions that inform irrigation policy in Africa. The paper concludes by offering a definition of ‘farmer-led irrigation’ that embraces a range of interaction between producers and commercial, government and non-government agencies, and identifies priority areas for research on the growth potential and impact of such interactions and strategies for their future development

A distributed TOPMODEL for modelling impacts of land-cover change on river flow in upland peatland catchments

There is global concern about headwater management and associated impacts on river flow. In many wet temperate zones peatlands can be found covering headwater catchments. In the UK there is major concern about how environmental change, driven by human interventions, has altered the surface cover of headwater blanket peatlands. However, the impact of such land-cover changes on river flow is poorly understood. In particular, there is poor understanding of the impacts of different spatial configurations of bare peat or well-vegetated, restored peat on river flow peaks in upland catchments. In this paper, a physically based, distributed and continuous catchment hydrological model was developed to explore such impacts. The original TOPMODEL, with its process representation being suitable for blanket peat catchments, was utilized as a prototype acting as the basis for the new model. The equations were downscaled from the catchment level to the cell level. The runoff produced by each cell is divided into subsurface flow and saturation-excess overland flow before an overland flow calculation takes place. A new overland flow module with a set of detailed stochastic algorithms representing overland flow routing and re-infiltration mechanisms was created to simulate saturation-excess overland flow movement. The new model was tested in the Trout Beck catchment of the North Pennines of England and found to work well in this catchment. The influence of land cover on surface roughness could be explicitly represented in the model and the model was found to be sensitive to land cover