585 research outputs found
Improving rainwater-use in Cabo Verde drylands by reducing runoff
Dryland agriculture in Cabo Verde copes with steep slopes, inadequate practices, irregular intense rain, recurrent
droughts, high runoff rates, severe soil erosion and declining fertility, leading to the inefficient use of rainwater.
Maize and beans occupy N80% of the arable land in low-input, low-yielding subsistence farming. Three collaborative
field trialswere conducted in different agroecological zones to evaluate the effects ofwater-conservation techniques
(mulching of crop residue, a soil surfactant and pigeon-pea hedges) combinedwith organic amendments (compost
and animal or green manure) on runoff and soil loss. During the 2011 and 2012 rainy seasons, three treatments and
one control (traditional practice) were applied to 44- and 24-m2 field plots. A local maize variety and two types of
beanswere planted. Runoff and suspended sedimentswere collected and quantified after each daily erosive rainfall.
Runoff occurred for rainfalls≥50mm(slope b10%, loamy Kastanozem),≥60mm(slope≤23%, silt–clay–loam Regosol)
and≥40mm(slope≤37%, sandy loam Cambisol). Runoffwas significantly reduced only with themulch treatment
on the slope N10% and in the treatment of surfactant with organic amendment on the slope b10%. Soil loss
reached 16.6, 5.1, 6.6 and 0.4 Mg ha−1 on the Regosol (≤23% slope) for the control, surfactant, pigeon-pea and
mulch/pigeon-pea (with organic amendment) treatments, respectively; 3.2, 0.9, 1.3 and 0.1 Mg ha−1 on the
Cambisol (≤37% slope) and b0. 2Mg ha−1 for all treatments and control on the Kastanozem(b10% slope). Erosion
was highly positively correlated with runoff. Mulch with pigeon-pea combinedwith an organic amendment significantly
reduced runoff and erosion fromagricultural fields on steep slopes, contributing to improved use of rainwater
at the plot level. Sustainable land management techniques, such as mulching with pigeon-pea hedges and an
organic amendment, should be advocated and promoted for the semiarid hillsides of Cabo Verde prone to erosion
to increase rainwater-use and to prevent further soil degradation
Soil and water conservation strategies and impact on sustainable livelihood in Cape Verde – Case study of Ribeira Seca watershed
Cape Verde, located off the coast of Senegal in western Africa, is a volcanic archipelago where a combination of
human, climatic, geomorphologic and pedologic factors has led to extensive degradation of the soils. Like other
Sahelian countries, Cape Verde has suffered the effects of desertification through the years, threatening the livelihood
of the islands population and its fragile environment. In fact, the steep slopes in the ore agricultural islands,
together with semi-arid and arid environments, characterized by an irregular and poorly distributed rainy season,
with high intensity rainfall events, make dryland production a challenge. To survive in these fragile conditions,
the stabilization of the farming systems and the maintenance of sustainable yields have become absolute priorities,
making the islands an erosion control laboratory. Soil and water conservation strategies have been a centerpiece of
the government0s agricultural policies for the last half century. Aiming to maintain the soil in place and the water
inside the soil, the successive governments of Cape Verde have implemented a number of soil and water conservation
techniques, the most common ones being terraces, half moons, live barriers, contour rock walls, contour
furrows and microcatchments, check dams and reforestation with drought resistant species. The soil and water
conservation techniques implemented have contributed to the improvement of the economical and environmental
conditions of the treated landscape, making crop production possible, consequently, improving the livelihood
of the people living on the islands. In this paper, we survey the existing soil and water conservation techniques,
analyze their impact on the livelihood condition of the population through a thorough literature review and field
monitoring using a semi-quantitative methodology and evaluate their effectiveness and impact on crop yield in
the Ribeira Seca watershed. A brief discussion is given on the cost and effectiveness of the techniques to reduce
soil erosion and to promote rainfall infiltration. Finally, we discuss the critical governance factors that lead to the
successful implementation of such strategy in a country with scarce natural resources
Modification of the lithospheric stress field by lateral variations in plate‐mantle coupling
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95471/1/grl26475.pd
Are Small GTPases Signal Hubs in Sugar-Mediated Induction of Fructan Biosynthesis?
External sugar initiates biosynthesis of the reserve carbohydrate fructan, but the molecular processes mediating this response remain obscure. Previously it was shown that a phosphatase and a general kinase inhibitor hamper fructan accumulation. We use various phosphorylation inhibitors both in barley and in Arabidopsis and show that the expression of fructan biosynthetic genes is dependent on PP2A and different kinases such as Tyr-kinases and PI3-kinases. To further characterize the phosphorylation events involved, comprehensive analysis of kinase activities in the cell was performed using a PepChip, an array of >1000 kinase consensus substrate peptide substrates spotted on a chip. Comparison of kinase activities in sugar-stimulated and mock(sorbitol)-treated Arabidopsis demonstrates the altered phosphorylation of many consensus substrates and documents the differences in plant kinase activity upon sucrose feeding. The different phosphorylation profiles obtained are consistent with sugar-mediated alterations in Tyr phosphorylation, cell cycling, and phosphoinositide signaling, and indicate cytoskeletal rearrangements. The results lead us to infer a central role for small GTPases in sugar signaling
Upper- and mid-mantle interaction between the Samoan plume and the Tonga-Kermadec slabs
Mantle plumes are thought to play a key role in transferring heat from the core\u2013mantle
boundary to the lithosphere, where it can significantly influence plate tectonics. On impinging
on the lithosphere at spreading ridges or in intra-plate settings, mantle plumes may generate
hotspots, large igneous provinces and hence considerable dynamic topography. However, the
active role of mantle plumes on subducting slabs remains poorly understood. Here we show
that the stagnation at 660 km and fastest trench retreat of the Tonga slab in Southwestern
Pacific are consistent with an interaction with the Samoan plume and the Hikurangi plateau.
Our findings are based on comparisons between 3D anisotropic tomography images and 3D
petrological-thermo-mechanical models, which self-consistently explain several unique
features of the Fiji\u2013Tonga region. We identify four possible slip systems of bridgmanite in the
lower mantle that reconcile the observed seismic anisotropy beneath the Tonga slab
(VSH4VSV) with thermo-mechanical calculations
Long‐term dietary shift and population decline of a pelagic seabird — A health check on the tropical Atlantic?
Better before worse trajectories in food systems? An investigation of synergies and trade-offs through climate-smart agriculture and system dynamics
Food systems face multiple challenges simultaneously: provision to a growing population, adaptation
to more extreme and frequent climate change risks, and reduction of their considerable greenhouse gas (GHG)
emissions. Food system interventions and policies give rise to synergies and trade-offs that emerge over time due
to the dynamic nature and interconnections of system elements. Analysis of an entire food system is necessary to
identify synergies that bring simultaneous benefits and mitigate trade-offs, both short- and long-term.
OBJECTIVE: Our study aims to inform the sustainable transformation of food systems by identifying short- and
long-term synergies and trade-offs in the climate-smart village (CSV) Lawra-Jirapa in northern Ghana under the
current practices, technologies, policies, and trends of population growth, extreme events, and climate change
impacts
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