“Dryland Ecosystems and its Problems” 6. Revegetation in arid and semiarid areas of West Africa<BR>Planting strategy in the Sahel region of west Africa and introduction of social forestry extension method in the semis arid areas

Abstract Growing water shortages have been a systemic risk around the world, especially in arid and semi-arid areas, with seriously threatening global food security and human well-being. Reasonable and accurate evaluations of the water shortages of cultivated lands provide scientific reference for irrigation strategies. In this study, to better understand the distribution and cause of water scarcity for the arid and semiarid areas, we used the arable land water scarcity index (AWSI), based on water footprint theory to accurately estimate the temporal and spatial patterns of the AWSI of Inner Mongolia in China over 1999–2018, and further reveal the key factors influencing the AWSI distribution. The AWSI distribution pattern of Inner Mongolia was high in southwest and low in northeast, with an average value of 0.63 and suffering from high water stress for a long time. The AWSI presented an increasing trend in 1999–2018, with slow in west (change rate2%) and fast in east (2%). The main factors that significantly affected the AWSI were precipitation, relative humidity, and agricultural planting area. This study can provide scientific reference for the formulation of agricultural water management and sustainable use strategies in arid and semiarid areas.

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Distinct assembly processes and determinants of soil microbial communities between farmland and grassland in arid and semiarid areas

Applied and Environmental Microbiology ◽

10.1128/aem.01010-21 ◽

2021 ◽

Author(s):

Aiai Xu ◽

Jie Liu ◽

Zhiying Guo ◽

Changkun Wang ◽

Kai Pan ◽

...

Keyword(s):

Microbial Community ◽

Variable Selection ◽

Microbial Communities ◽

Soil Microbial Community ◽

Environmental Gradient ◽

Soil Microbial Communities ◽

Soil Microbial ◽

Semiarid Areas ◽

Arid And Semiarid Areas ◽

Arid And Semiarid

It is critical to identify the assembly processes and determinants of soil microbial communities to better predict soil microbial responses to environmental change in arid and semiarid areas. Here, soils from 16 grassland-only, 9 paired grassland and farmland, and 16 farmland-only sites were collected across the central Inner Mongolia Plateau covering a steep environmental gradient. Through analyzing the paired samples, we discovered that land uses had strong effects on soil microbial communities, but weak effects on their assembly processes. For all samples, although no environmental variables were significantly correlated with the net relatedness index (NRI), both the nearest taxon index (NTI) and the β-nearest taxon index (βNTI) were most related to mean annual precipitation (MAP). With the increase of MAP, soil microbial taxa at the tips of the phylogenetic tree were more clustered, and the contribution of determinism increased. Determinism (48.6%), especially variable selection (46.3%), and stochasticity (51.4%) were almost equal in farmland, while stochasticity (75.0%) was dominant in grassland. Additionally, Mantel tests and redundancy analyses (RDA) revealed that the main determinants of soil microbial community structure were MAP in grassland, but mean annual temperature (MAT) in farmland. MAP and MAT were also good predictors of the community composition (the top 200 dominant OTUs) in grassland and farmland, respectively. Collectively, in arid and semiarid areas, soil microbial communities were more sensitive to environmental change in farmland than in grassland, and unlike the major impact of MAP on grassland microbial communities, MAT was the primary driver of farmland microbial communities. Importance As one of the most diverse organisms, soil microbes play indispensable roles in many ecological processes in arid and semiarid areas with limited macrofaunal and plant diversity, yet the mechanisms underpinning soil microbial community are not fully understood. In this study, soil microbial communities were investigated along a 500 km transect covering a steep environmental gradient across farmland and grassland in the areas. The results showed that precipitation was the main factor mediating the assembly processes. Determinism was more influential in farmland, and variable selection of farmland was twice that of grassland. Temperature mainly drove farmland microbial communities, while precipitation mainly affected grassland microbial communities. These findings provide new information about the assembly processes and determinants of soil microbial communities in arid and semiarid areas, consequently improving the predictability of the community dynamics, which have implications for sustaining soil microbial diversity and ecosystem functioning, particularly under global climate change conditions.

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RESEARCH NEEDS RELATED TO MUNICIPAL WASTEWATER RENOVATION AND REUSE IN ARID AND SEMIARID AREAS

Municipal Wastewater in Agriculture ◽

10.1016/b978-0-12-214880-4.50024-x ◽

1981 ◽

pp. 453-461

Author(s):

Thomas G. Bahr

Keyword(s):

Municipal Wastewater ◽

Research Needs ◽

Semiarid Areas ◽

Arid And Semiarid Areas ◽

Arid And Semiarid

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Grasses for Arid and Semiarid Areas

Forages ◽

10.1002/9781119436669.ch17 ◽

2020 ◽

pp. 313-330

Author(s):

Daren D. Redfearn ◽

Keith R. Harmoney ◽

Alexander J. Smart

Keyword(s):

Semiarid Areas ◽

Arid And Semiarid Areas ◽

Arid And Semiarid

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The role of unsaturated zone in estimating groundwater recharge in arid and semiarid areas as depicted by geochemical tracers

E3S Web of Conferences ◽

10.1051/e3sconf/20199812007 ◽

2019 ◽

Vol 98 ◽

pp. 12007

Author(s):

Tianming Huang ◽

Baoqiang Ma ◽

Yin Long ◽

Zhonghe Pang

Keyword(s):

Groundwater Recharge ◽

Unsaturated Zone ◽

Surface Boundary ◽

Recharge Rate ◽

Semiarid Area ◽

Near Surface ◽

Geochemical Tracers ◽

Semiarid Areas ◽

Arid And Semiarid Areas ◽

Arid And Semiarid

In arid and semiarid area, the recharge rate is relatively limited and the unsaturated zone (UZ) is commonly thick. The moisture in the UZ may represent the water infiltrating from precipitation during the past decades to thousands of years. Therefore, the multiple geochemical tracers in soil moisture, including Cl (chloride mass balance), 3H (tritium peak displacement), NO3, 2H, 18O, can be used to estimate diffuse recharge rate and related recharge characteristics. Based on 45 UZ profiles with maximum depth of 62 m in the Ordos Basin in NW China, a typical arid and semiarid area, we has used multiple geochemical tracers to study the following recharge informations: (1) reconstruction of groundwater recharge history, (2) determination of groundwater recharge mechanism, and (3) assessment of impact of vegetation changes on groundwater recharge. The results show that the soil texture (epically the shallow soil), vegetation and precipitation mainly control the recharge rate. This study also found that shallow groundwater in arid and semiarid areas is often not in equilibrium with near-surface boundary conditions. To estimate present recharge information, the UZ must be considered. The whole recharge process from precipitation to groundwater cannot be well understood unless the UZ have been included in arid and semiarid areas.

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