TITLE:
Soil Properties and Land Capability Evaluation in a Mountainous Ecosystem of North-West Cameroon
AUTHORS:
P. Azinwi Tamfuh, E. Temgoua, P. Wotchoko, A. Boukong, D. Bitom
KEYWORDS:
Land Evaluation, Fertility Capability Evaluation, Nutrient Status, Mountainous Ecosystem, Bafut, North-West Cameroon
JOURNAL NAME:
Journal of Geoscience and Environment Protection,
Vol.6 No.7,
July
6,
2018
ABSTRACT: Up to date, tropical mountainous ecosystems still lack in depth information on soil and environmental characteristics which are major factors limiting optimum crop production. The objective of this work was to study soil characteristics and to evaluate the land capability level for the production of some common tropical crops in mountainous ecosystem soils of North West Cameroon. Soil sampling was done following a randomized complete block design (RCBD) with four replications for three topographic positions (upslope, midslope and footslope) and at two depths (0 - 20 cm and 20 - 100 cm). It was completed by standard laboratory analyses. The fertility capability classification (FCC) system enabled to identify soil limitations and to classify soils into FCC units. Land and climate were evaluated by simple limitation and parametric methods. Globally, the soils were dark-colored, sandy clayey to clayey, compact and very acidic (pHH2O = 4.3 - 5.8). The organic matter (3.7% - 5.1% dry matter), total nitrogen (0.08% - 0.56%) and available phosphorus (22.1 to 30.9 mg⋅kg−1) recorded for the 0 - 20 cm depth then reduced with depth but midslope values were also lower. The C/N ratio varied between 9 and 45. Low C/N values appeared mostly in 0 - 20 cm depth at the upslope and downslope soils and subsurface soils of midslope position. Exchangeable Ca was very low to low (1.43 - 3.6 cmol + kg−1), Mg was very low to low (0.39 - 1.5 cmol + kg−1), K was low to medium (0.2 - 0.54 cmol + kg−1) and Na was very low (−1). The sum of exchangeable bases was very low (3.02 - 5.19 cmol + kg−1), cation exchange capacity was low to moderate (8.60 - 25.6 cmol + kg−1) and base saturation was very low to low (19.27% - 36.97%). Leaching of bases under heavy rainfall is a major cause of soil acidification under humid topical ecosystems. The Ca/Mg/K ratio was unbalanced and Mg was the most relatively concentrated base in all the soils. There was a clear variation of most of the soil properties along the slope and with depth. The soils were classified in the FCC system as aek for the upslope soils, Caek for the midslope soils and Cagk for the footslope soils. The principal limitations to production of huckleberry, beans, maize and potatoes were heavy rainfall, wetness, steep slope, soil texture/structure and low soil fertility. These constraints might be overcome by farming at the end of the raining season, contour ploughing, terracing, fertilization and liming.