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Noulè,koun, Florent,Lamers, John P.A.,Naab, Jesse,Khamzina, Asia Elsevier Scientific Pub.Co 2017 Forest ecology and management Vol.385 No.-
<P><B>Abstract</B></P> <P>In the Sudano-Sahelian zone of West Africa, where deforestation and cropland soil degradation occur at alarming rates, the (re-)introduction of trees on degraded lands can improve and sustain farming systems and landscapes. The shoot and root morphological traits of five woody species introduced to degraded cropland were assessed with a particular focus on the survival, early establishment and growth of saplings subjected to manuring (1kg per plant) and drip irrigation (0.5L of water per plant per day). Functional traits of the woody above- and belowground organs of field-grown plants were monitored for the first 15months after planting, covering two growing (rainy) seasons and one dry season. The high survival rate (>60%), combined with a very low incidence rate (<1%), for all species was evidence of successful establishment overall. The highest survival rates (94–100%) were observed in <I>Jatropha curcas</I> L., <I>Leucaena leucocephala</I> Lam. and <I>Moringa oleifera</I> Lam. The mortality rate of the most drought-sensitive species <I>Parkia biglobosa</I> Jacq. could be reduced ten-fold through supplemental irrigation during the dry season. The fast-growing <I>L. leucocephala</I>, <I>M. oleifera</I> and <I>J. curcas</I> had higher values for shoot-level traits than did the slow-growing <I>Anacardium occidentale</I> L. and <I>P. biglobosa</I>. Fertilization and irrigation enhanced the shoot growth of both the fast and slow growers during the dry and growing seasons. In contrast, belowground development was either increased or reduced by fertilization and irrigation during the growing and dry seasons, but the slow growers demonstrated a more plastic response to these treatments than did the fast growers. Among the studied traits, the relative growth rate of plant as a whole (i.e. shoots and roots combined) exhibited the greatest plastic response to resource availability, thus suggesting its application in screening candidate species for afforestation efforts. Overall, the five studied species were considered suitable for the afforestation of degraded croplands, while the early growth and establishment of saplings could be boosted by irrigation and a supply of manure.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The response of fast-growing species to manuring was pronounced in shoots. </LI> <LI> Slow growers invested more in developing roots rather than developing shoots. </LI> <LI> In the presence of water scarcity, slow growers performed better than fast growers. </LI> <LI> Relative growth rate was the most indicative measure of species suitability for afforestation. </LI> </UL> </P>
Kumar, Navneet,Khamzina, Asia,Tischbein, Bernhard,Knö,fel, Patrick,Conrad, Christopher,Lamers, John P.A. ACADEMIC PR 2019 JOURNAL OF ARID ENVIRONMENTS Vol.162 No.-
<P><B>Abstract</B></P> <P>Global warming is predicted to increase water scarcity in many drylands worldwide. In Central Asia, one of the most intensively irrigated dryland agricultural regions, climate change is likely to exacerbate the regional water supply–demand gaps, particularly in downstream areas. The withdrawal of degraded, highly salinized croplands from irrigated farming in favor of tree plantations that effectively utilize saline groundwater may contribute to irrigation water saving, which can generate valuable ecosystem services and provide rural income opportunities. To facilitate the spatial planning of afforestation in the lower Amudarya region, we developed a hydrological algorithm to map the spatio-temporal pattern of water supply–demand. The resulting map, based on seven-year continuous data of cropping pattern and corresponding irrigation dynamics, rainfall, and evapotranspiration at 250 m resolution, revealed the overly irrigated areas from which excess water can be redistributed to water-stressed areas. Furthermore, combining this information with spatial data on marginally productive croplands and with water requirement of tree plantations showed that 67% of these croplands are characterized by water availability sufficient for the introduction of salt-tolerant tree species. The algorithm developed is of potential use for defining the feasibility of introducing alternative (tree) crops with known growth and water use characteristics.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Remote sensing aided a water balance estimation in data-scarce irrigated drylands. </LI> <LI> Spatio-temporal dynamics of surface water is key for dryland afforestation planning. </LI> <LI> Cell-based hydrological algorithm offers spatial guidance for regional afforestation. </LI> <LI> Over 60% of marginal cropland receives enough water for conversion to agroforestry. </LI> </UL> </P>
Free transverse vibrations of an elastically connected simply supported twin pipe system
Müge Balkaya,Metin O. Kaya,Ahmet Sa lamer 국제구조공학회 2010 Structural Engineering and Mechanics, An Int'l Jou Vol.34 No.5
In this paper, free vibration analyses of a parallel placed twin pipe system simulated by simply supported-simply supported and fixed-fixed Euler-Bernoulli beams resting on Winkler elastic soil are presented. The motion of the system is described by a homogenous set of two partial differential equations, which is solved by a simulation method called the Differential Transform Method (DTM). Free vibrations of an elastically connected twin pipe system are realized by synchronous and asynchronous deflections. The results of the presented theoretical analyses for simply supported Euler-Bernoulli beams are compared with existing ones in open literature and very good agreement is demonstrated.