Arid Lands Research Articles

Dust emission efficiency of compacted soils as a function of amount of abrader and soil texture

Abrasion by blown sand is a main wind erosion process for compacted soils, such as dry lake basins and the undisturbed grassland that are widely distributed in arid land. Dust emission efficiency (δ) is defined as the ratio of the dust flux to the sediment transport rate from a soil surface. Previous studies mostly focused on the influence of wind velocity or soil properties on δ and rarely considered the amount of abrader in blown sand; furthermore, most of their experiments used loose soils involving three physical mechanisms of dust emission. In this study, we explored the mechanism of dust emission from compacted soils caused by saltation bombardment of the abrader making use of wind tunnel experiments and using the mass flux of the abrader (q) to represent the abrasion intensity of blown sand. The results showed that dust flux (F) generated from the compacted soil by abrasion and bombardment was linear with q, and δ was always positively correlated with q and with the silt and clay content in soils. Taking into account both the amount of abrader and the texture of the soil being abraded, we proposed and validated a model of dust emission efficiency for compacted soil.

Indigenous communities’ perceptions reveal threats and management options of wild edible plants in semiarid lands of northwestern Kenya

BackgroundUnderstanding how local communities perceive threats and management options of wild edible plants (WEPs) is essential in developing their conservation strategies and action plans. Due to their multiple use values, including nutrition, medicinal, construction, and cultural as well as biotic and abiotic pressures, WEPs are exposed to overexploitation, especially within arid and semiarid lands, and hence the need to manage and conserve them. We demonstrate how an understanding of indigenous communities’ perceptions could be achieved through an integrated participatory approach involving focus group discussions (FGDs) and field plot surveys.MethodsWe conducted three FGDs between October 2020 and April 2021 within three community units in northwestern Kenya with different socioeconomic and environmental characteristics. We subsequently surveyed 240 field plots of size 1 ha each to assess threats facing WEPs within a 5 km buffer radius in every study community. We compared ranks of threats and management options across community units.ResultsRankings of threats and management options differed across the three study communities. We obtained strong positive linear relationships between field and FGD rankings of threats facing WEPs. Climate change, overstocking, overharvesting, and invasive species were the highest-ranked threats. Mitigation of climate change, local knowledge preservation, selection, propagation, processing, and marketing of WEPs ranked high among possible management options irrespective of the socioeconomic and environmental characteristics of the community unit.ConclusionsOur approach emphasizes the relevance of leveraging indigenous communities’ perceptions and conducting field plot surveys to assess threats and management options for WEPs. Evaluating the effectiveness and cost–benefit implications of implementing the highly ranked management options could help determine potentially suitable habitats of the WEPs for conservation and management purposes, especially for priority WEPs.

Essential Oil Composition of Grindelia squarrosa from Southern Idaho.

Grindelia squarrosa is an arid lands herb that has been used in Native American traditional medicine, is a potential source of pharmacologically active compounds, and has been explored as a source of biofuel. The purpose of this work was to examine the essential oil composition of G. squarrosa from southern Idaho. Gas chromatographic methods revealed the essential oil of G. squarrosa var. serrulata to be rich in monoterpenoids, α-pinene (21.9%), limonene (17.1%), terpinolene (10.6%), and borneol (6.5%). The essential oil composition of G. squarrosa from Idaho is similar to that previously reported from specimens collected from Montana and confirms the volatile phytochemistry of plants growing in North America. The major essential oil components were screened for antimicrobial activity against respiratory and dermal pathogens. (-)-β-Pinene showed strong antibacterial activity against Streptococcus pneumoniae (MIC 39.1 μg/mL) and (-)-borneol showed strong activity against Staphylococcus aureus (MIC 78.1 μg/mL).

Responses of soil fauna community under changing environmental conditions

Soil faunas account for 23% of known animal species and play a crucial role in ecosystem processes such as mineralizing nutrients, regulating microbial community composition, forming soil aggregates, and enhancing primary productivity. However, due to global climate change, population density, community composition, and distribution patterns of soil fauna vary. Understanding the responses of soil fauna to major environmental change facilitate the conservation of biodiversity. Therefore, a review work of recent researches for analysing the effects of key environmental factors on soil fauna, such as warming, drought, food quality, and soil physical-chemical properties was studied. For most species, warming may exert a positive effect on their abundance and population development, however, it can inhibit the survival and reproduction of hibernating species. Drought leads to low soil porosity and water holding capacity, which reduces soil fauna population and changes their community composition. Drought also can reduce the coverage of flora and alter microclimate of the soil surface, which in turn indirectly reduces fauna abundance. Climate warming and elevated atmospheric carbon dioxide can reduce litter quality, which will force soil fauna to change their dietary choices (from higher-quality foods to poor quality foods) and reduce reproduction for survival. However, it is still predicted that enhanced species richness of plant (or litter) mixtures will positively affect soil fauna diversity. Habitat loss caused by the deterioration of soil physical-chemical property is primary factor affecting soil fauna. We mainly discuss the threats of increased salinity (a major factor in arid land) to soil fauna and their potential responses to anthropogenic disturbance in saline soils. The increase in soil salinity can override other factors that favour habitat specialists, leading to negative effects on soil fauna. Moreover, we find that more studies are needed to explore the responses of soil fauna in saline soils to human activities. And the relationship of important ecological processes with soil fauna density, community structure, and diversity needs to be redefined.

The Changing Faces of Farmer-Led Irrigation: Lessons from Dynamic Irrigation Trajectories in Kenya and Zimbabwe

Farmer-led irrigation is valued for its resilience and ability to cope with shocks and benefit from opportunities. Yet, typologies of farmer-led irrigation are mostly static categorisations without analysing farmers’ decision-making over time, and without studying ‘failed’ cases. We therefore analysed temporal changes in farmers’ irrigation strategies to expand, downscale or cease practices as part of wider livelihood decisions and aspirations. This longitudinal study presents irrigation trajectories of 32 farmers in the arid lands of two contrasting socioeconomic settings in Kenya and Zimbabwe. Data were collected through multiple rounds of surveys and in-depth interviews. Results show that farmers frequently alternated strategies or ceased or restarted operations over the years, both by force and choice. Although many farmers were able to start, expand or sustain irrigation, not all managed or aspired to remain engaged in irrigated farming, even if the enabling environment was conducive for market-oriented irrigation development. We therefore conclude that farmers’ needs cannot always be expressed in general terms of growth or commercial farming, nor can they always be satisfied by improving the enabling environment, which may be based on static ontologies of diverse types of farmers.

Co-designed Practical Use of Probabilistic Climate Advisories among Smallholder Farmers: A Balance between Confidence and Caution

Especially for smallholder farmers with limited land and financial resources, farming in arid and semi-arid lands (ASALs), where season-to-season rainfall fluctuation dictates production, is a risky business. Through participatory approaches, this study compares deterministic and probabilistic interpretations of climate forecasts and their use by smallholder farmers through a crop-growing season. The study revealed that deterministic advisories are good for smallholder farmers only when formulated from forecasts with higher accuracy than the historical climatological distribution. Otherwise, they cause farm loss in terms of labor and inputs. On the other hand, probabilistic advisories help farmers spread the risk to cater to all the uncertainty and in so doing bring out a balance between confidence and caution. However, farmers must be supported with enough sensitization to comprehend forecast probability, translate it into probabilistic advisories and use that to plan and manage farm activities. The findings support the hypothesis providing packaged climate products in transparent probabilistic terms in place of deterministic form can overcome inherent credibility challenges. The study’s conclusion highlights important takeaways and new understandings of the advantage of using probabilistic advisories among resource-poor smallholder farmers.

The Influence of Communication Messages on Adoption of Contagious Bovine Pleuropneumonia (CBPP) Vaccine among Arid and Semi-Arid Lands (ASAL) Pastoralists in Kenya

Purpose: The purpose was to establish influence of communication messages on adoption of Contagious Bovine Pleuropneumonia (CBPP) Vaccine among Arid and Semi-Arid Lands (ASAL) pastoralists in Kenya. Messages were studied under parameters of inoculation site, benefits, required frequency of vaccination and side effects. The focus on the vaccine messaging was informed by the slow pace of adoption of live T1 vaccines currently being used to eradicate CBPP in Kenya. Diffusion of innovation and social learning theories were used to support the study.
 Methodology: Study population were pastoralists in Narok South Sub County. 468 respondents inclusive of qualitative and quantitative samples where 440 responded to questionnaire, 24 in focus group discussions, and 4 in key informant interviews participated. Multi stage, purposive, simple random, systematic and stratified sampling techniques were then employed to come up with respondents. Statistical Package for Social Scientists (SPSS) version 20.0 was used to analyze data, which was presented using regression coefficients and ANOVA.
 Findings: CBPP messaging influenced respondents to vaccinate although some had more influence than others. Messages on inoculation site, benefits, required frequency of vaccination side effects and communal vaccinations were important for the survival of their cattle and significantly influenced the decisions of respondents to vaccinate against the disease. Moreover, messages helped them to know important information details such as vaccination venues, and costs of vaccination and availability of the veterinary officers. CBPP vaccine messages attributes were key in the success of influencing respondents. However, the messaging ran into already held misinformation by some pastoralists confirming earlier study that vaccination rate was at 20-60% because some skipped the exercise.
 Unique Contribution to Theory, Practice and Policy: CBPP vaccine messages and attributes significantly influenced CBPP vaccinations decisions among pastoralists. This study validated diffusion of innovation and social learning theories that innovation-decision process is essentially an information seeking and processing activity in which an individual is motivated to reduce uncertainty about the advantages and disadvantages of the innovation. For policy and practice, this study recommends development of communication plans, and packaging of CBPP vaccine messages for dissemination in the ASALs where disease is prevalent. Considering that CBPP is a trans-boundary disease, these plans and messages could be harmonized across ASAL counties to enable consistency and coherence.

Review on Composition, Nutritional and Medicinal Value of Camel

The camels are the most dominant and widely distributed animal in tropical and subtropical continents of Africa and Asia. They make an important contribution to human survival and utilization of these dry and arid lands. The objective of this review is to describe the general compositions of camel milk and its nutritive and medicinal values. Camels are an important source of milk, meat, hides, wool and serve as a source of prestige for their owners. Camel’s products like milk, meat and urine has nutritional value as well as therapeutic for different human diseases especially in the pastoral communities. Milk is the lacteal secretion of mammary gland of mammals. As it is well known, milk is the first natural food of young mammals during the period immediately after birth. Camel milk is one of the most valuable food resources in the nomadic society and has high nutritive and therapeutic values, due to its essential elements like minerals, vitamins, fatty acids, carbohydrates and protective proteins such as, lactoferrin, lacto peroxidase, lysozme, peptidoglycan recognition protein and immunoglobulins. Camel milk contains disease-fighting immunoglobulins, which are small in size, allowing penetration of antigens and boosting the effectiveness of the immune system. Camel milk has a medicinal properties suggesting that, this milk contains protective proteins, which may have a possible role for enhancing immune defense mechanism. Due to its protective proteins and other components, camel’s milk is important for the treatment of diseases like, dropsy, jaundice, spleen ailment, tuberculosis, asthma, anemia, autoimmune diseases (autism), constipation, crohn’s diseases, and liver cirrhosis also serve as beauty products. Pastoralists have indigenous knowledge in treating their animals and themselves using milk. Because they are living at periphery and remote area where social services are in scarce or even absence and therefore, they depends on traditional medicines. Camel milk is among the items used as traditional medicine in pastoral communities. Generally, Camel milk is extremely nutritious and safe for consumption and has a high therapeutic value, so experimental researches should be conducted specially on the medicinal value of camel milk.

The Microbiology of Biological Soil Crusts.

Biological soil crusts are thin, inconspicuous communities along the soil atmosphere ecotone that, until recently, were unrecognized by ecologists and even more so by microbiologists. In its broadest meaning, the term biological soil crust (or biocrust) encompasses a variety of communities that develop on soil surfaces and are powered by photosynthetic primary producers other than higher plants: cyanobacteria, microalgae, and cryptogams like lichens and mosses. Arid land biocrusts are the most studied, but biocrusts also exist in other settings where plant development is constrained. The minimal requirement is that light impinge directly on the soil; this is impeded by the accumulation of plant litter where plants abound. Since scientists started paying attention, much has been learned about their microbial communities, their composition, ecological extent, and biogeochemical roles, about how they alter the physical behavior of soils, and even how they inform an understanding of early life on land. This has opened new avenues for ecological restoration and agriculture.

Epidemiological Dynamics of Foot-and-Mouth Disease in the Horn of Africa: The Role of Virus Diversity and Animal Movement.

The Horn of Africa is a large area of arid and semi-arid land, holding about 10% of the global and 40% of the entire African livestock population. The region's livestock production system is mainly extensive and pastoralist. It faces countless problems, such as a shortage of pastures and watering points, poor access to veterinary services, and multiple endemic diseases like foot-and-mouth disease (FMD). Foot-and-mouth disease is one of the most economically important livestock diseases worldwide and is endemic in most developing countries. Within Africa, five of the seven serotypes of the FMD virus (FMDV) are described, but serotype C is not circulating anymore, a burden unseen anywhere in the world. The enormous genetic diversity of FMDV is favored by an error-prone RNA-dependent RNA polymerase, intra-typic and inter-typic recombination, as well as the quasi-species nature of the virus. This paper describes the epidemiological dynamics of foot-and-mouth disease in the Horn of Africa with regard to the serotypes and topotypes distribution of FMDV, the livestock production systems practiced, animal movement, the role of wildlife, and the epidemiological complexity of FMD. Within this review, outbreak investigation data and serological studies confirm the endemicity of the disease in the Horn of Africa. Multiple topotypes of FMDV are described in the literature as circulating in the region, with further evolution of virus diversity predicted. A large susceptible livestock population and the presence of wild ungulates are described as complicating the epidemiology of the disease. Further, the husbandry practices and legal and illegal trading of livestock and their products, coupled with poor biosecurity practices, are also reported to impact the spread of FMDV within and between countries in the region. The porosity of borders for pastoralist herders fuels the unregulated transboundary livestock trade. There are no systematic control strategies in the region except for sporadic vaccination with locally produced vaccines, while literature indicates that effective control measures should also consider virus diversity, livestock movements/biosecurity, transboundary trade, and the reduction of contact with wild, susceptible ungulates.

The conflicts of agricultural water supply and demand under climate change in a typical arid land watershed of Central Asia

Study Region. The Bosten Lake basin. Study Focus. The irrigated agriculture distributed in arid/semi-arid areas is of great significance for. food security and sustainable development. However, the shortage of water resources. limits agricultural development in these areas, and the water distribution pattern under. climate change is also uncertain. In this research, the Bosten Lake basin was selected. as the study area, and the monthly agricultural water supply (AWS) and demand. (AWD) in the historical and future periods were evaluated. New Hydrological Insights for the Region. Supported by the hydrological model and evapotranspiration model, the AWS and. AWD of the watershed were first evaluated, and 37 GCMs under CMIP6 were used to. expand the study to future periods, a novel downscaling scheme consisting of IDW and. BMA is used to increase the reliability of the results. The supply and demand of. agricultural water in the future scenarios within the region are revealed. In the. forthcoming future (the 2030 s), the watershed will maintain the warming and wetting. trend in the historical period. In the long-term future (the 2060 s), agricultural water. scarcity will become more severe, especially under the high emission scenario. (ssp585). The adaption strategies to address climate change have also been. proposed, and efficient water conveyance is highly recommended. This study is. expected to provide a reference for water resources management in arid/semi-arid. watersheds.

Detection of vertebrates from natural and artificial inland water bodies in a semi-arid habitat using eDNA from filtered, swept, and sediment samples.

Biomonitoring is vital for establishing baseline data that is needed to identify and quantify ecological change and to inform management and conservation activities. However, biomonitoring and biodiversity assessment in arid environments, which are predicted to cover 56% of the Earth's land surface by 2100, can be prohibitively time consuming, expensive, and logistically challenging due to their often remote and inhospitable nature. Sampling of environmental DNA (eDNA) coupled with high-throughput sequencing is an emerging biodiversity assessment method. Here we explore the application of eDNA metabarcoding and various sampling approaches to estimate vertebrate richness and assemblage at human-constructed and natural water sources in a semi-arid region of Western Australia. Three sampling methods: sediment samples, filtering through a membrane with a pump, and membrane sweeping in the water body, were compared using two eDNA metabarcoding assays, 12S-V5 and 16smam, for 120 eDNA samples collected from four gnammas (gnamma: Australian Indigenous Noongar language term-granite rock pools) and four cattle troughs in the Great Western Woodlands, Western Australia. We detected higher vertebrate richness in samples from cattle troughs and found differences between assemblages detected in gnammas (more birds and amphibians) and cattle troughs (more mammals, including feral taxa). Total vertebrate richness was not different between swept and filtered samples, but all sampling methods yielded different assemblages. Our findings indicate that eDNA surveys in arid lands will benefit from collecting multiple samples at multiple water sources to avoid underestimating vertebrate richness. The high concentration of eDNA in small, isolated water bodies permits the use of sweep sampling that simplifies sample collection, processing, and storage, particularly when assessing vertebrate biodiversity across large spatial scales.

Variation in Spatial Distribution of Spider Fauna Between Agricultural and Arid Land of Shujabad, Punjab, Pakistan

Spiders are the little creature that have key role in ecosystem especially in terms of biodiversity controlling agent. This survey-based study was conducted on spiders to assess their diversity in two different habitat conditions of Pakistan. In this study, 29 species, 15 genera and 7 families were collected. Lycosidae family had the highest diversity 55% followed by Araneidae (29%), Gnaphosidae (3%), Salticidae (3%), Oxyopidae (0.35%), Tetragnathidae (7%) and Thomisidae (3%). The Hippasa, Pardosa, Eriovixia, Araneus, Tetragnatha, Sitticus and Gnaphosa were most dominant genus out of observed 15 genera. Furthermore, the dominant species in agricultural land includes; Pardosa sutherlandi, Araneus nympha, Eriovixia lagleizai and Tetragnatha javana. The arid land was dominated by Hippasa holmerae, Hippasa pisaurina, Pardosa leucopalpis, Thomisus dostinikus and Gnaphosa harpax. Moreover, results for Simpson and Shannon indices revealed that the maximum diversity was found in habitat C as 82% on Simpson scale and 84% on Shannon scale. The Sorenson similarity indices revealed there is no more overlap between the different habitats species diversity. The study concluded that the agricultural land having scattered plants like mangos had higher diversity of spiders. 

A novel TF molecular switch-mechanism found in two contrasting ecotypes of a psammophyte, Agriophyllum squarrosum, in regulating transcriptional drought memory

BackgroundPrior drought stress may change plants response patterns and subsequently increase their tolerance to the same condition, which can be referred to as “drought memory” and proved essential for plants well-being. However, the mechanism of transcriptional drought memory in psammophytes remains unclear. Agriophyllum squarrosum, a pioneer species on mobile dunes, is widely spread in Northern China’s vast desert areas with outstanding ability of water use efficiency. Here we conducted dehydration-rehydration treatment on A. squarrosum semi-arid land ecotype AEX and arid land ecotype WW to dissect the drought memory mechanism of A. squarrosum, and to determine the discrepancy in drought memory of two contrasting ecotypes that had long adapted to water heterogeneity.ResultPhysiological traits monitoring unveiled the stronger ability and longer duration in drought memory of WW than that of AEX. A total of 1,642 and 1,339 drought memory genes (DMGs) were identified in ecotype AEX and WW, respectively. Furthermore, shared DMGs among A. squarrosum and the previously studied species depicted that drought memory commonalities in higher plants embraced pathways like primary and secondary metabolisms; while drought memory characteristics in A. squarrosum were mainly related to response to heat, high light intensity, hydrogen peroxide, and dehydration, which might be due to local adaptation to desert circumstances. Heat shock proteins (HSPs) occupied the center of the protein-protein interaction (PPI) network in drought memory transcription factors (TF), thus playing a key regulatory role in A. squarrosum drought memory. Co-expression analysis of drought memory TFs and DMGs uncovered a novel regulating module, whereby pairs of TFs might function as molecular switches in regulating DMG transforming between high and low expression levels, thus promoting drought memory reset.ConclusionBased on the co-expression analysis, protein-protein interaction prediction, and drought memory metabolic network construction, a novel regulatory module of transcriptional drought memory in A. squarrosum was hypothesized here, whereby recurrent drought signal is activated by primary TF switches, then amplified by secondary amplifiers, and thus regulates downstream complicated metabolic networks. The present research provided valuable molecular resources on plants’ stress-resistance basis and shed light on drought memory in A. squarrosum.

Opuntia spp.: An Overview of the Bioactive Profile and Food Applications of This Versatile Crop Adapted to Arid Lands

Opuntia spp. are crops well adapted to adverse environments and have great economic potential. Their constituents, including fruits, cladodes, and flowers, have a high nutritional value and are rich in value-added compounds. Cladodes have an appreciable content in dietary fiber, as well as bioactive compounds such as kaempferol, quercetin, and isorhamnetin. Fruits are a major source of bioactive compounds such as phenolic acids and vitamin C. The seeds are mainly composed of unsaturated fatty acids and vitamin E. The flowers are also rich in phenolic compounds. Therefore, in addition to their traditional uses, the different plant fractions can be processed to meet multiple applications in the food industry. Several bakery products have been developed with the incorporation of cladode flour. Pectin and mucilage obtained from cladodes can act as edible films and coatings. Fruits, fruit extracts, and fruit by-products have been mixed into food products, increasing their antioxidant capacity and extending their shelf life. Betalains, obtained from fruits, can be used as food colorants and demonstrate promising applications as a sensor in food packaging. This work reviews the most valuable components of the different fractions of this plant and emphasizes its most recent food applications, demonstrating its outstanding value.

Contributions of plant litter to soil microbial activity improvement and soil nutrient enhancement along with herb and shrub colonization expansions in an arid sandy land

Shrubs and herbs are two important types of vegetation that play a pivotal role in combating land desertification in arid sandy land. Yet, the effects of plant litter on sandy soil microbial activities and soil nutrients during the shrub and herb colonization process are still unclear. Here, contributions of plant litter to soil microbial activity improvement and soil nutrient enhancement along herb and shrub colonization expansion interfaces were studied in an arid sandy landscape. Plant litter mass, soil water content, pH, nutrient content, extracellular enzyme activities, and microbial community structure (taxon composition, α-diversity, β-diversity, and co-occurrence pattern) of soils at depths of 0–10 cm were examined relative to the colonization processes of shrubs and herbs (shrub and herb vegetation → sand-shrub and sand-herb interface → a sand dune) in an arid sandy land. We found that the processes of both herb and shrub colonization significantly increased litter cumulative mass at the soil surface to soil depths of 5 cm, and shrub colonization contributed several folds more litter than herb colonization. Plant litter input significantly decreased soil pH, accelerated soil extracellular enzyme activities, increased abundances of some microbial phyla (Actinobacteria, Chloroflexi, Acidobacteria, Gemmatimonadetes, Patescibacteria, Armatimonadetes, Ascomycota, Moritierellomycota, and Chytridiomycota), enhanced both prokaryotic and fungal α-diversities, altered both prokaryotic and fungal communities, and promoted complexity of microbial networks during both herb and shrub colonization. As a result, microorganisms actively participated in litter decomposition and soil nutrient enhancement. Nevertheless, shrub colonization process exhibited greater potential in nutrient input than herb colonization process due to its greater plant litter input, though both colonization played a comparable role in accelerating soil enzyme activity and improving soil microbial community diversity and co-occurrence. Therefore, xeromorphic shrubs are still more important plants than herbs should be used for vegetation construction and ecological restoration in arid sandy land.

Effects of Irrigation Interval and Planting Spacing on the Establishment and Growth of Faidherbia albida (Del.) A. Chev. Transplants in Arid Land Soils

The study aimed to assess the establishment of Faidherbiaalbida transplants under the effect of irrigation intervals and plantingspacing in the field conditions. It consisted of three irrigation intervals of5, 10 and 15 days and three planting spacings of 1x1 m, 1x2 m, and 2x3m; and it was conducted in the premises of the Forest Research Center,Khartoum, during May 2008 to June 2009. The results showed that thetemporal growth rate of F. albida shoot heights was greater in winter(November-February), but it was seriously slowed during the summerperiod (March-June). The shoot height, diameter and biomass growth ofF. albida increased with decreasing irrigation intervals; the growth ofthese parameters was highest in 5 days interval and lowest in 15 daysinterval. Planting spacings had no direct definite effect on F. albidaseedlings’ growth parameters. Even though, in the longer irrigationintervals, transplants’ growth tented to be greater in the wider spacing.Root biomass development seemed to be higher in the longer irrigationinterval regimes. There were no significant differences in the foliarnutrient content of the transplants between the different irrigationintervals. The values of mineral elements measured in this study areindicative of moderate nutrient supply for the F. albida transplants

Factors Influencing Farmers’ Adaptations to Climate Change and Variability in Arid and Semi-Arid Lands of Kitui and Kajiado Counties, Kenya

A study was conducted in the arid and semi-arid lands of Kitui and Kajiado counties to determine factors that influence farmers’ adaptation to climate change and variability. Quantitative and qualitative approaches were applied in the study to gain insights into the adaptation strategies used by farmers to cope with climate change and variability and factors that influence their adoption. A mix of purposeful and multistage stratified random sampling methods were used to select households which formed the unit of analysis in the study. Results of the Chi-square test for independence indicated that there was an association between the adoption of different adaptation strategies to climate change and variability and the study sites (p< 0.05). In addition, scrutiny of the results of logistic regression analysis showed that gender, education level, farming experience, age, and county of the respondent significantly (p<0.05) influenced the adoption of adaptation strategies to climate variability and extremes in the study area. The study identified the need for increased agricultural extension training and sensitisation on climate change among farmers to ensure that feasible adaptation strategies are promoted and factors influencing their adoption are leveraged

Reclamation during oasification is conducive to the accumulation of the soil organic carbon pool in arid land

Reclamation during oasification is conducive to the accumulation of the soil organic carbon pool in arid land

Vapor buoyancy increases clear-sky thermal emission

The molar mass of H2O (18 g mol−1) is smaller than that of dry air (29 g mol−1), which makes humid air lighter than dry air with the same temperature and pressure. This vapor buoyancy (VB) effect has been traditionally considered small in large-scale climate dynamics and even neglected in some leading climate models. Here, using theory and aquaplanet simulations with prescribed surface temperatures, we show that VB increases tropospheric air temperature, and that the warmer atmosphere emits more clear-sky thermal radiation by about 2–4 W m−2 in the dry subtropical areas, a significant radiative effect. We then analyze Coupled Model Intercomparison Project Phase 6 simulations with prescribed sea surface temperatures and realistic topography. The results show that VB can increase clear-sky thermal radiation by up to 5 W m−2 over the ocean and about 15 W m−2 over the subtropical arid land regions. The radiative effect over arid land is amplified by a substantial increase of surface temperature due to VB. Our results highlight the role of VB in regulating Earth’s energy balance both at the top of the atmosphere and at the land surface. This study points to new ways to improve climate models and their simulated energy balance.