Knowledge for Development

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Assessing land degradation and desertification using vegetation index data: current frameworks and future directions

The scientific requirements for degradation and desertification monitoring systems are identified: (i) validation of methodologies in a robust and comparable manner and (ii) detection of degradation at minor intensities and magnitudes. Thomas Higginbottom and Elias Symeonakis of the School of Science and the Environment, Manchester Metropolitan University, UK apply the statistical and ecological frameworks for assessing land degradation and desertification using vegetation index data. They also review the development of multi-temporal analysis as a desertification assessment technique, with a focus on how current practice has been shaped by controversy and dispute. The techniques commonly employed are examined from both a statistical and ecological point of view, and recommendations are made for future research directions. The paper is part of the Remote Sensing Special Issue 'Remote Sensing of Land Degradation in Drylands'.   (Remote Sensing, 10/10/2014)

31/12/2014


Pesticides are more toxic for soil organisms in dry soil and at enhanced temperatures

Scientists from the LOEWE Biodiversity and Climate Research Centre (BiK-F), the Goethe University and the ECT Oekotoxikologie GmbH, demonstrate that soil organisms in dry soil and at enhanced temperatures are more sensitive to pesticides. Singularly and combined, these factors lower the toxicity threshold of fungicides (pyrimethanil) for springtails (Collembolas), tiny hexapods that participate in essential soil functions, decomposing organic material and building up humus. Both conditions – drier soils and higher temperature – may occur more often in the future due to climate change and thus fungicide application under these conditions could further harm the soil biota essential for soil fertility.   (Phys.org, 11/09/2014)

29/10/2014


Desert locusts: abundant, highly mobile solitary populations

CIRAD scientists, in collaboration with all locust control centres in West Africa, Northwest Africa, Sudan and Pakistan, and support of the FAO, organised a substantial operation to collect populations of the desert locust (Schistocerca gregaria) during remission periods. This project provided a clearer understanding of population dynamics and made it possible to determine their size during remission periods compared to during invasion periods. It was previously thought that solitary locusts only existed in small populations and were liable to extinction as a result of the arid conditions in the Sahara. The results contradicted this belief: the solitary locust populations almost all showed high genetic diversity, indicating that population levels do not fall sufficiently at the end of invasions to affect their genetic diversity and homogeneity. In fact, populations are much larger during remission periods than previously thought. These and other conclusions of this project will support invasion surveillance and prevention strategies: solitary populations, which travel fast, can very quickly discover zones in which conditions are conducive for reproduction. During remission periods, those zones must therefore be identified as soon as possible, so as to act immediately to prevent invasions.   (CIRAD, 06/2014)

21/07/2014


Evolution of some observed climate extremes in the West African Sahel

Ly Mouhamed and colleagues of the AGRHYMET Regional Center in Niger, have analysed the evolution of some extreme temperature and precipitation indices over a large area of West Africa. Using daily observations of rainfall and temperature available at the AGRHYMET Regional Center for the 1960–2010 period, they identified a general warming trend throughout the region during that period, namely through a negative trend in the number of cool nights, and more frequent warm days and warm spells. This was the case not only for locations inside the continent, but also for those in coastal areas. Trends in rainfall related indices are not as uniform as the ones in temperatures. Nevertheless, a general tendency of decreased annual total rainfall and maximum number of consecutive wet days characterises the study period. Policy implications of these trends may include investment and promotion of low cost and environmentally friendly energy production systems, the redesign of infrastructure and production systems to account for higher risks of losses due to floods and/or droughts, and the promotion of research for more heat tolerant crop/animal species and cultivars/breeds.   http://www.sciencedirect.com/science/article/pii/S2212094713000066   (Weather and Climate Extremes, 25/08/2013)

10/04/2014


Crop adaptation to climate change in the semi-arid zone in Tanzania

This article by Ola T. Westengen and Anne K Brysting from the University of Oslo, Norway, present a case study of the role of genetic resources and seed systems in adapting to climatic stress from in semi-arid agro-ecological zone of Tanzania. In this case, crop adaptation involves the adoption of improved maize varieties combined with continued use of local varieties of both maize and sorghum. Analysis shows that households receiving extension service and owning livestock are more likely to switch to drought-tolerant varieties as a response to climatic stress than those without these assets. The seed system in the study area consists of both formal and informal elements. The informal channels supply the highest quantities of both sorghum and maize seeds. Recycling of improved varieties of maize is common and the majority of households practice seed selection. Detailed assessment of the three different categories of genetic resources – local, improved and farmer-recycled varieties – reveals that drought tolerance is more frequently reported as a reason for growing local varieties than for growing improved varieties of maize and sorghum.    http://www.agricultureandfoodsecurity.com/content/3/1/3/abstract    (Agriculture and Food Security, 01/02/2014)

27/02/2014


Plant production could decline as climate change affects soil nutrients

The findings of a study led by Matthew Bowker, assistant professor of forest soils and ecosystem ecology at Northern Arizona University, shows that, as drylands of the world become even drier, levels of nutrients in the soil will be affected, and their imbalance could affect agricultural productivity around the globe. The statistical model he helped develop for the study suggests that as the climate becomes more arid, nitrogen will decrease and phosphorus will increase.   http://www.eurekalert.org/pub_releases/2013-10/nau-ppc103113.php  (EurekAlert, 31/10/2013)

17/12/2013


Scientists deploy iron-rich pearl millet against malnutrition

Researchers working under the HarvestPlus programme coordinated by CIAT and IFPRI, explain how iron-rich millet, when part of an everyday diet, can combat malnutrition of children. Of note is the development and successful deployment of an iron-rich pearl millet variety in India developed by ICRISAT that is not only nutritionally enhanced, but also drought-tolerant and high-yielding. This variety is adapted to drylands.    http://www.ifpri.org/blog/breeding-health-scientists-deploy-iron-rich-pearl-millet-against-malnutrition (IFPRI, 26/08/2013)

5/11/2013


Scientists deploy iron-rich pearl millet against malnutrition

Researchers working under the HarvestPlus programme coordinated by CIAT and IFPRI, explain how iron-rich millet, when part of an everyday diet, can combat malnutrition of children. Of note is the development and successful deployment of an iron-rich pearl millet variety in India developed by ICRISAT that is not only nutritionally enhanced, but also drought-tolerant and high-yielding. This variety is adapted to drylands.        (IFPRI, 26/08/2013)     

18/09/2013


Thirty-five water conservation methods for agriculture, farming, and gardening

This four-part article by Big Picture Agriculture provides a list of 35 different water conservation methods that are ideal for small and medium sized farms and gardens. Some of the methods described are adapted to drier climates, others to higher altitude cultivation, though most apply to climatic conditions and crops found in ACP countries. (Big Picture Agriculture, 02/2012) 

10/04/2013


Diversity keeps grasslands resilient to drought, climate change

A Kansas State University-led study looked at the drought tolerance of 426 species of grass from around the world. The goal was to better understand how grasslands in different parts of the world may respond to the changes in frequency and severity of drought in the future. Grasslands have several important ecological functions: they convert and store carbon dioxide, are a food source for grazing animals like cattle and bison, and help cool the surrounding atmosphere. The goal of the study was to drought-stress the species of grass to identify the ones that could survive without water for over a week’s time. Researchers developed a drought index for the tested species based on the data. The index details each species' tolerance to drought and can help ecologists understand why grasslands around the world are composed of their species.http://www.eurekalert.org/pub_releases/2012-08/ksu-dkg080812.php(EurekAlert, 8/8/2012)

26/09/2012


The CASCADE project: Making drylands more resilient by studying catastrophic shifts

Resilience of landscapes is sometimes stretched to a tipping point and adverse changes then follow quickly. At the moment, little is known about the connection between environmental stresses and catastrophic shifts. CASCADE will investigate a range of dryland ecosystems in southern Europe to study a range of physical and socio-economical drivers and obtain a better understanding of sudden shifts in drylands that may lead to major losses in biodiversity and concomitant ecosystem services. By focusing on vulnerable drylands as the target ecosystems, it builds further on existing knowledge regarding shifts in these ecosystems. CASCADE will improve our understanding of the biogeochemical mechanisms underlying sudden and catastrophic shifts, and of the key biotic and abiotic factors influencing these processes. The CASCADE approach will develop a common-ground participatory approach that will serve as the basis of the sustainable management of the ecosystems, the biodiversity within these ecosystems, and the services provided by the ecosystems.(via Wageningen University, 18/6/2012)

16/08/2012


Good news on using recycled sewage treatment plant water for irrigating crops

A new study eases concerns that irrigating crops with water released from sewage treatment plants – an increasingly common practice in arid areas of the world – fosters emergence of the antibiotic-resistant bacteria that cause thousands of serious infections each year. Arid and semi-arid areas of the world are plagued by severe water shortages, which are expected to increase as a result of growing population and global climate change. As a result, more areas are turning to treated wastewater (TWW) to irrigate croplands. In Israel, for instance, TWW provides more than half of the water used for irrigation. The researchers wanted to find out if long-term irrigation with treated wastewater enhances antibiotic resistance in soil microbial communities, which could potentially be transferred through agricultural produce to clinically relevant bacteria. The authors found that levels of antibiotic-resistant bacteria and genes for antibiotic resistance in fields and orchards irrigated with freshwater and TWW were essentially identical, suggesting that antibiotic-resistant bacteria that enter soil by irrigation are not able to survive or compete in that environment. The authors say there is ‘cause for cautious optimism’ that irrigating with TWW is not increasing the prevalence of bacteria resistant to the antibiotics they studied. (EurekAlert, 13/6/2012)

11/07/2012


Scientists developing crop for livestock in dry climates

Scientists at the University of Liverpool, UK are working with international partners to develop new forage crop for the hot and dry climate of regions. Researchers are using next generation DNA sequencing technology to obtain molecular genetic markers for easier selection of the best varieties of a grass called Panicum turgidum, also known as desert bunchgrass or taman. This plant is already used for livestock feed, but the new project will allow identification of the best varieties of the grass for hot and dry regions. (UoL IIB; 27/3/2012)

4/06/2012


Plants remember drought, change responses to survive

A research team from the University of Nebraska-Lincoln, US, has shown that plants subjected to a previous period of drought are able to better withstand new periods of water stress. The research confirms for the first time the scientific basis for what home gardeners and nursery professionals have often learned through hard experience: Transplants do better when water is withheld for a few days to drought harden them before the move. This phenomenon of drought hardening was documented when scientists compared the reaction of plants that had been previously stressed by withholding water to those not previously stressed. The pre-stressed plants bounced back more quickly the next time they were dehydrated. Specifically, the non-strained plants wilted faster than trained plants and their leaves lost water at a faster rate than trained plants. Plant nurseries adopting this drought hardening process could ensure smallholder farmers in drought-prone regions. (ScienceDaily, 15/03/2012)

1/05/2012


Solar power for crop irrigation

For fruits, cereals and leguminous plants such as oranges, wheat, beans and olives to grow in hot and dry climates, they must be irrigated regularly. And very often the water used comes from deep wells. In Egypt, many farmers currently use diesel generators to water their fields. A model project in Upper Egypt shows that other methods are possible. Here, a photovoltaic stand-alone system takes care of irrigating a wheat field. Concentrator photovoltaic system (CPV) modules – which, due to their higher degree of effectiveness and their particular construction, require far less space than traditional PV modules – supply the energy, while Fresnel lenses concentrate the rays of the sun onto pinhead-sized multi-junction solar cells. With the aid of a tracking motor, the CPV cells, which are attached to a pillar, follow the sun precisely to achieve an optimized yield of solar light. They supply the energy for a submersible pump that pumps the water up from a well that is 105 feet deep and for a small desalination unit that satisfies farmers’ potable water requirements. The CPV cells also supply the energy for PV-module trackers, the monitoring and control system and an air-conditioning unit that cools the utility room of the facility.(Frauenhofer-Gesellschaft via AlphaGalileo, 2/8/2011)

30/08/2011


Scientists discover agave’s tremendous potential as new bioenergy feedstock

An article in Global Change Biology Bioenergy reviews the suitability of Agave (Agave americana) as a bioenergy feedstock that can sustain high productivity in spite of poor soil and stressful climatic conditions accompanying climate change. Agave, which grows successfully under hot, dry conditions, is currently used in the production of beverages, food, and fiber, and has only recently been considered a promising source of biofuel.E. Garcia-Moya, Professor of Botany at the Colegio de Postgraduados en Ciencias Agricolas in Texcoco, Mexico, and colleagues were able to assess Agave’s potential as a biomass crop by reviewing Agave research published in English and Spanish. Agave has comparable productivity to high productivity crops such as corn and Eucalyptus and much larger biomass yields than most desert plants. Unlike most crops, Agave would continue to thrive under increased temperatures and variable precipitation accompanying global climate change. In addition, elevated levels of atmospheric CO2 would increase productivity.(Source: AlphaGalileo, 17 February 2011)

22/03/2011


Improving water productivity of crop-livestock systems in drought-prone regions

The publication of a special issue of Experimental Agriculture presents evidence from Ethiopia, Zimbabwe and India, and captures current understanding of strategies to improve water productivity in drought-prone crop-livestock systems. Crop-livestock systems in sub-Saharan Africa (SSA) are mostly rainfall-dependent and based on fragmented marginal lands that are vulnerable to soil erosion, drought and variable weather conditions. The threat of water scarcity in these systems is real, due to expanding demand for food and feed, climate variability and inappropriate land use. Strategies and policies to reduce rural poverty should not only target increasing food production but should also emphasize improving water productivity at farm, landscape, sub-basin and higher levels. In drought-prone rural areas, an increase of 1% in crop water productivity makes available at least an extra 24 litres of water a day per person. Moreover, farming systems with efficient use of water resources are commonly responsive to external and internal drivers of change. (Source: ILRI, 14 January 2011)

14/02/2011


Working across borders - Harnessing the potential of cross-border activities to improve livelihood security in the Horn of Africa drylands

The Humanitarian Policy Group of the Overseas Development Institute, London, UK, argues in their study of September 2010 ‘Working across borders’ that there remains limited understanding of the nature, magnitude and value of cross-border livelihood activities in the Horn of Africa. The key messages are Mobile pastoralist systems often cross international borders. There is a need for more research, policy and practice efforts to better understand and exploit the potential of cross-border activities to enhance drought management, contribute to national economies, and improve local livelihoods and food security in the Horn of Africa. Governments in the region should cooperate in granting legal and economic legitimacy to informal cross-border trade exchanges and step up collective efforts to control trans-boundary animal diseases. Regional bodies can play a pivotal coordination role and provide the enabling policy environment and legal framework to regulate cross-border dynamics. Donors should support these processes. There is also a need to recognize that a timely, adequate and comprehensive response to drought must also focus on border areas and support cross-border activities. (Source: Reliefweb, September 2010)

5/11/2010


In drought-prone Sahel, scientists roll out innovative system for producing vegetables

Dov Pasternak, an agricultural scientist with the Niger hub of the India-based ICRISAT, announced new progress in disseminating an innovative system for irrigated vegetable production called the ‘African Market Garden’. Speaking at the African Green Revolution Forum that took place 2-4 september 2010 in Accra Ghana, Pasternak explained that ‘the “African Market Garden” combines efficient drip irrigation to save water, energy and labor with improved crop management to boost farmers' vegetable yields and economic returns.’ The centrepiece of the new system is a, low-pressure drip irrigation unit, which is installed in a field that comprises clusters measuring 500 square meters. The African Market Garden drastically reduces one of the main limitations of traditional vegetable growing - its excessive labor and energy requirements. In addition to the reduced drudgery for women and lower production costs, the system of community market gardening makes the new system more accessible to farmers by better enabling them to manage the set-up costs. (Source: Sciencedaily, 5 September 2010)

5/11/2010


Plant scientists move closer to making any crop drought-tolerant

A collaborative team of scientists, led by researchers at the Medical College of Wisconsin (USA) has made a significant advance on the discovery last year of pyrabactin (by Sean Cutler of the University of California, Riverside). Pyrabactin is a synthetic chemical that mimics a naturally produced stress hormone in plants to help them cope with drought conditions. Plants naturally produced a stress hormone, abscisic acid (ABA), in modest amounts to help them survive drought by inhibiting growth. ABA has already been commercialized for agricultural use. But it has at least two disadvantages: it is light-sensitive and costly to make. Pyrabactin, on the other hand, is relatively inexpensive, easy to make, and not sensitive to light. But its drawback is that, unlike ABA, it does not turn on all the ‘receptors’ in the plant that need to be activated for drought-tolerance to fully take hold. By understanding how pyrabactin works and with more research like the current one, the drawbacks of pyrabactin can be studied, and other more effective chemicals can be developed more readily for bringing drought-resistance to plants. (Source: Check Biotech, 26 August 2010)

5/11/2010