TITLE:
Variation in Total Soil Organic Carbon Stocks in Relation to Some Land Use Systems in the Bamenda Highlands, Cameroon
AUTHORS:
Christian Tegha Kum, Aaron Suh Tening, Martin Ngwabie, Cornelius Tsamo
KEYWORDS:
Soil, Soil Organic Carbon, Land Use Systems, Bamenda Highlands, Soil CO2 Emissions
JOURNAL NAME:
Journal of Geoscience and Environment Protection,
Vol.9 No.9,
September
29,
2021
ABSTRACT: Climate change and food
security are among the pressing challenges facing humanity in the 21st century. Soil organic carbon (SOC) stocks, total nitrogen (TN), texture, and
bulk density (BD) are important soil properties, which control climate change.
Three land use systems (smallholder farmlands, grazing lands, and forest lands) that
coexist in the Bamenda Highlands (BH)
influence ecosystem services and induce soil degradation with the loss of SOC. The objective of
this study was to evaluate the variation of SOC and some soil physicochemical
properties as affected by the three land use systems (LUS). A total of 21
composite soil samples collected from 7 microclimatic zones of BH following “S”
shape plots to the depth of 0 - 30 cm, were analysed for moisture content (MC),
SOC, TN, BD, available phosphorus (Av.P), pH and texture. The results revealed
that grazing land had the lowest mean sand content (40.79 ± 4.07). Mean MC, TN and SOC
(%) content were significantly higher (p in
forest land than those in the
grazing land and smallholder farmlands. Conversely, BD and Av.P
were significantly higher (p in
smallholder farmlands than grazing and forest lands probably due to different litter accumulation and
agricultural practices. Moisture content and TN
revealed positive significant correlations (p 0.05) with SOC, while BD and Av.P revealed negative
significant correlations (p 0.05). Mean SOC density in smallholder farmlands (132.91 ± 9.48 tC/ha) was the lowest among the three land
use types. Losses in CO2 equivalence, as a result of land use change from forest lands to
smallholder farmlands were 137.33 t/ha while that from grazing lands to smallholder
farmlands were 109.13 t/ha. Total organic carbon (TOC)
stocks differed significantly (p 0.05) from smallholder farmlands (10.73 Mt) to
forest lands (91.13 Mt). A
sustainable farming technique that enhances SOC
sequestration and minimizes soil CO2 emissions is therefore
recommended to replace tillage ridges formation commonly practiced by
smallholder farmers.