Acid sands of South-eastern Cambodia: Their origin, properties and management for upland crops
Year: 2019
Type: dissertation
Abstract: Deep sand and sand on clay profiles occupy a large proportion of the Cambodian landscape.However, the diversity and the factors affecting origin and formation of sand profiles of Cambodia has not been explored and analysed in detail.Moreover, currently there is limited knowledge about the edaphic properties of these sands particularly those that are limiting to agricultural production.The present study concentrated on origin and properties and some management methods to ameliorate acidity of sands in south-eastern Cambodia.From texture analysis of 19 profiles sampled along toposequences in four study areas (Kampot, Tramkak, Ponhea Krek, and Rolea Bíer/Tuek Phos districts), sand fractions ranging from 63 to 200 μm and 200 to 600 μm were predominant in most profiles, except for Kampot 4, where the fraction was dominated by sand grains from 200 to 600 μm and five profiles from Kampong Chhnang province, where the three medium-coarse sand fractions (63-200, 200-600 and 600-2000 μm) were equally dominant.Clay content was generally < 100 g/kg within 0-80 cm depth but mostly increased from 60 to 160 cm depth.Sub-angular and sub-rounded grains were the major shapes of sand grains in most profiles (20-80 %).Sub-angular shapes of sand grains in Tramkak and Kampong Chhnang generally decreased from the site at the base of mountain to the lower part of the toposequence.In contrast, percentages of sub-rounded grains were higher in the profile in the lower part of the toposequence.Moderately spherical sand grains were the major class in all profiles, ranging from 40-75 % of grains.Based on the above analysis and their proximity to the mountains, the sand profiles sampled along toposequences in four study areas of south-east Cambodia showed the major influence of in situ weathering of siliceous parent materials and to a lesser extent colluvial transport of sands.There was no evidence of long range transport of the sand grains or of any aeolian processes in re-working of the sands.
Author: S. Hin
Language: English
Subfield: Soil Science
Domain: Life Sciences
SDG: Life on land
Open Access status: green
OpenAlex ID: W2994469401