The Sahelian and Saharan dune systems of Niger. A comparison of their granulometric characteristics

Author(s):  
Ibrahim Mamane Sani ◽  
Issa Ousseïni
Shore & Beach ◽  
2021 ◽  
pp. 17-21
Author(s):  
A.T. Williams

Between the years 1200 and 1600, vast quantities of sand were brought inshore from offshore bars as a result of centuries of ferocious storms, to form a series of dune systems along the South Wales coastline. Today, as a result of many housing, leisure, and industrial developments only a few remnants exist. On one such remnant at Porthcawl, Wales, UK, became a caravan site in the 1930s, which was abandoned in 1993 for political reasons. Within 27 years a minimum of 120,000 m3 of sand was transported from the adjacent beach and formed dunes >4 m in height along a 400- m frontal edge that extended some 130 m inland, approximately a third of the site. Typical vegetation found along the frontal part of the system are Ammophila arenaria (marram), Agropyron junceiforme (sand couch grass) and Euphorbia maritimum (spurge). To the rear of the system, vegetation included Agrostis tenuis and stolonifera, (bent and creeping bent grass), Cirsium avense (creeping thistle), and Caluna vulgaris (heather). A 4-m-high and c. 3000m2 area of a vigorous stand of Hippophae rhamnoides (sea buckthorn) has also formed. The rapidity of dune formation and vegetation colonization is staggering.


2021 ◽  
Vol 9 (3) ◽  
pp. 153
Author(s):  
Murilo Alceu de Águas ◽  
Joaquim José Frazão ◽  
Leonardo Mariano do Nascimento ◽  
João Paulo Souza Carneiro ◽  
Ariel Muncio Compagnon ◽  
...  

Lowlands represent a significant portion of agricultural areas in the world. Thus, understanding the spatial variability of the chemical and granulometric characteristics of hydromorphic soils can contribute to improving soil management and fertility. The objective of this work was to characterize spatial dependence, spatialized chemical attributes, granulometry, and the ideal number of samples in irrigated hydromorphic soil. Soil sampling was conducted in a grid of 10x10 m, in the layers of 0–0.1 and 0.1–0.2 m, totalling 432 composite samples. The evaluated attributes are as follows: pH in water, H+Al, SOM, Ca, Mg, Al, P, K, CTC, V%, Cu, Fe, Zn, Mn, clay, silt, and sand. The texture of the area was classified as loamy–sandy and free in the 0–0.1 and 0.1–0.2 m layers, respectively. The coefficient of variation of the attributes ranged from 2.71% (0–0.1m) to 149.07% (0.1–0.2m). All the attributes studied exhibited moderate to strong spatial dependence. The sample grid with a sampling interval of 20 m referring to the 0–0.1 m layer proved to be adequate. The ideal number of simple samples per composite is 19 for granulometry and macronutrients, and 28 for the micronutrients in the 0–0.1 m layer.


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