Soil Organic Carbon Distribution in a Humid Tropical Plain of Cameroon: Interrelationships with Soil Properties

Table 2

Description of study sites and classification of representative soil profiles.

Site characteristics	Bamia series	Santchou series	Lelem series	Ntengie series	Bamengwi series
Geographical coordinates	Lat: 05° 17′ 51.5″ N, Long: 09° 55′ 00.9″ E	Lat: 05° 16′ 23.5″ N, Long: 09° 58′ 26.0″ E	Lat: 05° 12′ 02.5″ N, Long: 09° 59′ 54.0″ E	Lat: 05° 21′ 59.1″ N, Long: 10° 00′ 27.9″ E	Lat: 05° 15′ 03.09″ N, Long: 10° 05′ 22.77″ E
Land use/vegetation	Intensely cultivated farmland dominated by mixed crops, including cocoa, cocoyam, plantain, oil palm, and maize	Uncultivated grassland	Uncultivated patch (relics) of gallery forest, having wild palms, lianas, mixed trees, shrubs, and grass	Cultivated farmland with mixed crops, including maize, sweet potato, cowpea, okra, huckleberry, and pepper	Cultivated farmland with mixed perennial crops, including oil palm, cocoa, coffee, banana, and plantain
Soil management -Tillage type -Fertilization	Minimum tillage; Occasional fertilization	None; None	None; None	Conventional tillage; Regular fertilization	Minimum tillage; Occasional fertilization
Physiography	Foot slope, 2–5 % (strongly sloping), medium-gradient hill on straight concave slope, good external drainage and moderate internal drainage. Piedmont of the escarpment which limits the plain	Plain, 0 % (flat terrain), poor external drainage and moderate internal drainage	Plain, almost flat terrain (0-1%), good external drainage and moderate internal drainage	Plain, flat terrain (0–1%), good external and internal drainage	Plain, flat terrain (0–1%), good external drainage and moderate internal drainage
Relief/elevation	Foot slope, 751 m asl	Plain, 711 m asl	Plain, 716 m asl	Plain, 723 m asl	Plain, 740 m asl
Erosion	Signs of slight geologic erosion with presence of gentle rills on soil surface	No signs of erosion	No signs of erosion	No signs of erosion	No signs of erosion
Parent material	Granite	Alluvial sediments (for subsurface soil) and organic matter (for surface layer)	Alluvial sediments	Alluvial sediments	Alluvial sediments
Soil moisture regime	Udic	Udic/aquic	Udic/aquic	Udic/aquic	Udic/aquic
Soil temperature regime	Isohyperthermic	Isohyperthermic	Isohyperthermic	Isohyperthermic	Isohyperthermic
Soil classification: IUSS working group WRB, [58]	Eutric Cambisol	Abruptic Gleysol (Humic)	Endoclayic Luvisol (Gleyic)	Humi-Dystric Fluvisol	Gleyi-Humic Fluvisol (Eutric)
Soil classification: Soil survey staff [59]	Typic Eutrudepts	Mollic Endoaquents	Oxyaquic Paleudalfs	Oxyaquic Udifluvents	Mollic Udifluvents