The evaluation and exploitation of semi-arid lands: Australian experience

1977 ◽  
Vol 278 (962) ◽  
pp. 493-505 ◽  
Keyword(s):  
Unit Area ◽  
Arid Lands ◽  
Annual Rainfall ◽  
The North ◽  
Resource Degradation ◽  
Resource Inventory ◽  
Australian Experience ◽  
Vast Area ◽  
Semi Arid ◽  
Socio Economic Factors

Arid and semi-arid lands are areas where rainfall is too low or too unreliable for cropping or sown pastures. Australian arid and semi-arid lands comprise a single vast area extending to the 250 mm mean annual rainfall isohyet in the south and the 750 mm isohyet in the north. The grazeable areas are used for grazing of sheep or cattle under very extensive management, producing wool and meat for export. The industries have a low production per unit area, but are very efficient in terms of production per unit of labour. Graziers and administrators have had an overoptimistic perception of the land and climate which has led to varying degrees of resource degradation. Applied research into resource inventory, range condition and trend, stock carrying capacities, and droughts is described. The land and climate of arid and semi-arid Australia are comparable with those of other parts of the world, but socio-economic factors are very different.

scholarly journals The Case for New Domestic Animals

Oryx ◽  
1974 ◽  
Vol 12 (3) ◽  
pp. 351-360 ◽  
Author(s):  
Michael A. Crawford
Keyword(s):  
Wild Species ◽  
Domestic Animals ◽  
Arid Lands ◽  
Temperate Zone ◽  
Wild Animals ◽  
The North ◽  
Cattle Farming ◽  
Semi Arid

You do not grow bananas in the north of Scotland or raspberries in the Serengeti. Similarly temperate-zone cattle are not suited to Africa's semi-arid lands but giraffe and eland thrive. So these and other wild species, says the author, should be domesticated for such lands—40 per cent of Africa south of the Sahara is semi-arid—with cattle farming restricted to the highlands. In addition, research on new systems of management should aim to make use of the wild animals’ preferences for different grasses, bush and browse—from the tree-top using giraffe to the root-digging warthog.

SUSTAINABLE YIELD GROUNDWATER IN ARID AND SEMI-ARID LANDS IN TEXAS

2017 ◽  
Author(s):  
Ronald Green ◽  
◽  
F. Paul Bertetti ◽  
Beth Fratesi ◽  
Nathaniel J. Toll
Keyword(s):  
Arid Lands ◽  
Sustainable Yield ◽  
Semi Arid

scholarly journals Geochemical and isotopic evidence of groundwater salinization processes in the Essaouira region, north-west coast, Morocco

2021 ◽  
Vol 3 (7) ◽  
Author(s):  
Otman EL Mountassir ◽  
Mohammed Bahir ◽  
Driss Ouazar ◽  
Abdelghani Chehbouni ◽  
Paula M. Carreira
Keyword(s):  
Groundwater Recharge ◽  
West Coast ◽  
Exchange Process ◽  
Environmental Isotopes ◽  
Annual Rainfall ◽  
Groundwater Salinization ◽  
Rock Interaction ◽  
North West ◽  
The North ◽  
Water Rock Interaction

AbstractThe city of Essaouira is located along the north-west coast of Morocco, where groundwater is the main source of drinking, domestic and agricultural water. In recent decades, the salinity of groundwater has increased, which is why geochemical techniques and environmental isotopes have been used to determine the main sources of groundwater recharge and salinization. The hydrochemical study shows that for the years 1995, 2007, 2016 and 2019, the chemical composition of groundwater in the study area consists of HCO3–Ca–Mg, Cl–Ca–Mg, SO4–Ca and Cl–Na chemical facies. The results show that from 1995 to 2019, electrical conductivity increased and that could be explained by a decrease in annual rainfall in relation to climate change and water–rock interaction processes. Geochemical and environmental isotope data show that the main geochemical mechanisms controlling the hydrochemical evolution of groundwater in the Cenomanian–Turonian aquifer are the water–rock interaction and the cation exchange process. The diagram of δ2H = 8 * δ18O + 10 shows that the isotopic contents are close or above to the Global Meteoric Water Line, which suggests that the aquifer is recharged by precipitation of Atlantic origin. In conclusion, groundwater withdrawal should be well controlled to prevent groundwater salinization and further intrusion of seawater due to the lack of annual groundwater recharge in the Essaouira region.

scholarly journals Climatic Zone and Soil Properties Determine the Biodiversity of the Soil Bacterial Communities Associated to Native Plants from Desert Areas of North-Central Algeria

2021 ◽  
Vol 9 (7) ◽  
pp. 1359
Author(s):  
Elisa Bona ◽  
Nadia Massa ◽  
Omrane Toumatia ◽  
Giorgia Novello ◽  
Patrizia Cesaro ◽  
...  
Keyword(s):  
Soil Properties ◽  
Bacterial Communities ◽  
Arid Environment ◽  
Climatic Zone ◽  
Indigenous Plants ◽  
North Central ◽  
The North ◽  
Desert Areas ◽  
Plant Microbiota ◽  
Semi Arid

Algeria is the largest country in Africa characterized by semi-arid and arid sites, located in the North, and hypersaline zones in the center and South of the country. Several autochthonous plants are well known as medicinal plants, having in common tolerance to aridity, drought and salinity. In their natural environment, they live with a great amount of microbial species that altogether are indicated as plant microbiota, while the plants are now viewed as a “holobiont”. In this work, the microbiota of the soil associated to the roots of fourteen economically relevant autochthonous plants from Algeria have been characterized by an innovative metagenomic approach with a dual purpose: (i) to deepen the knowledge of the arid and semi-arid environment and (ii) to characterize the composition of bacterial communities associated with indigenous plants with a strong economic/commercial interest, in order to make possible the improvement of their cultivation. The results presented in this work highlighted specific signatures which are mainly determined by climatic zone and soil properties more than by the plant species.

Agriculture expansion and deforestation in seasonally dry forests of north-west Argentina

2005 ◽  
Vol 32 (2) ◽  
pp. 140-148 ◽  
Author(s):  
H. RICARDO GRAU ◽  
N. IGNACIO GASPARRI ◽  
T. MITCHELL AIDE
Keyword(s):  
Global Trends ◽  
North West ◽  
Conservation Policies ◽  
Seasonally Dry ◽  
The North ◽  
Agriculture Expansion ◽  
Soybean Price ◽  
Different Levels ◽  
Semi Arid ◽  
Arid Chaco

In Argentina, deforestation due to agriculture expansion is threatening the Semi-arid Chaco, one of the largest forested biomes of South America. This study focuses on the north-west boundary of the Argentine Semi-arid Chaco, where soybean is the most important crop. Deforestation was estimated for areas with different levels of soil and rainfall limitation for agriculture between 1972 and 2001, with a finer analysis in three periods starting in 1984, which are characterized by differences in rainfall, soybean price, production cost, technology-driven yield and national gross domestic product. Between 1972 and 2001, 588 900 ha (c. 20% of the forests) were deforested. Deforestation has been accelerating, reaching >28 000 ha yr−1 after 1997. The initial deforestation was associated with black bean cultivation following an increase in rainfall during the 1970s. In the 1980s, high soybean prices stimulated further deforestation. Finally, the introduction of soybean transgenic cultivars in 1997 reduced plantation costs and stimulated a further increase in deforestation. The domestic economy had little association with deforestation. Although deforestation was more intense in the moister (rainfall >600 mm yr−1) areas, more than 300 000 ha have already been deforested in the drier areas, suggesting that climatic limitations are being overcome by technological and genetic improvement. Furthermore, more than 300 000 ha of forest occur in sectors without major soil and rainfall limitations. If global trends of technology, soybean markets and climate continue, and no active conservation policies are applied, vast areas of the Chaco will be deforested in the coming decades.

Climatology and Trends of Climate Extremes of Temperature and Precipitation in Belo Monte Hydropower Plant – Eastern Amazon, Brazil

2021 ◽  
Author(s):  
Wanderson Luiz-Silva ◽  
Pedro Regoto ◽  
Camila Ferreira de Vasconcellos ◽  
Felipe Bevilaqua Foldes Guimarães ◽  
Katia Cristina Garcia
Keyword(s):  
Climate Change ◽  
Climate Extremes ◽  
Annual Rainfall ◽  
The South ◽  
North Central ◽  
Adaptation Capacity ◽  
The North ◽  
South Central ◽  
Daily Data ◽  
Belo Monte

<p>This research aims to support studies related to the adaptation capacity of the Amazon region to climate change. The Belo Monte Hydroelectric Power Plant (HPP) is in the Xingu River basin, in eastern Amazonia. Deforestation coupled with changes in water bodies that occurred in the drainage area of Belo Monte HPP over the past few decades can significantly influence the hydroclimatic features and, consequently, ecosystems and energy generation in the region. In this context, we analyze the climatology and trends of climate extremes in this area. The climate information comes from daily data in grid points of 0.25° x 0.25° for the period 1980-2013, available in http://careyking.com/data-downloads/. A set of 17 climate extremes indices based on daily data of maximum temperature (TX), minimum temperature (TN), and precipitation (PRCP) was calculated through the RClimDex software, recommended by the Expert Team on Climate Change Detection and Indices (ETCCDI). The Mann-Kendall and the Sen’s Curvature tests are used to assess the statistical significance and the magnitude of the trends, respectively. The drainage area of the Belo Monte HPP is dominated by two climatic types: an equatorial climate in the north-central portion of the basin, with high temperatures and little variation throughout the year (22°C to 32°C), in addition to more frequent precipitation; and a tropical climate in the south-central sector, which experiences slightly more pronounced temperature variations throughout the year (20°C to 33°C) and presents a more defined wet and dry periods. The south-central portion of the basin exhibits the highest temperature extremes, with the highest TX and the lowest TN of the year occurring in this area, both due to the predominant days of clear skies in the austral winter, as to the advance of intense masses of polar air at this period. The diurnal temperature range is lower in the north-central sector when compared to that in the south-central region since the first has greater cloud cover and a higher frequency of precipitation. The largest annual rainfall volumes are concentrated at the north and west sides (more than 1,800 mm) and the precipitation extremes are heterogeneous across the basin. The maximum number of consecutive dry days increases from the north (10 to 20 days) to the south (90 to 100 days). The annual frequency of warm days and nights is increasing significantly in a large part of the basin with a magnitude ranging predominantly from +7 to +19 days/decade. The annual rainfall shows a predominant elevation sign of up to +200 mm/decade only in the northern part of the basin, while the remainder shows a reduction of up to -100 mm/decade. The duration of drought periods increases in the south-central sector of the basin, reaching up to +13 days/decade in some areas. The results of this study will be used in the future as an important input, together with exposure, sensibility, and local adaptation capacity, to design adaptation strategies that are more consistent with local reality and to the needs of local communities.</p>

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