Abstract

Abakaliki is predominantly agrarian but continuous cropping is largely practiced due to population pressure. Consequently, there is effort to evolve strategies that would ensure sustainable productivity. This necessitated a research which was carried out to study carbon sequestration and assessment of fertility status of soil for agronomic potentials under different land use systems. Six different land uses each of 20 m × 20 m equivalent to 0.04 ha were identified with Global Positioning System (GPS) and used for the study. Auger and Core samples were randomly collected at 0-15 cm depth in ten different points in each land use for determination of carbon sequestration and fertility assessment. Data were subjected to standard deviation. Results of standard deviation showed high carbon sequestration of 66.83±16.03, 43.73±5.69, 34.51±1.57 and 32.90±0.85 t ha-1 for alley cropping, forest, fallow and grazing land uses compared to 4.56±11.82 and 3.48±12.30 t ha-1 for mixed cropping and continuously cultivated soil. Bulk densities and total porosities were not limiting to soil fertility for alley cropping, forest, fallow and grazing land uses but moderately limiting for mixed cropping and continuously cultivated soil. Soil pH, available phosphorus, nitrogen, organic carbon, calcium, magnesium and exchangeable acidity were generally high and not limiting to fertility status in alley cropping, forest, fallow and grazing land uses but low and limiting in mixed cropping and continuously cultivated soil. Alley cropping, forest, fallow and grazing fell into grade 2 ranking while mixed cropping and continuously cultivated soil were in Grades 3 and 4 fertility ranking for agronomic potentials, respectively. Deep feeder crops are recommended for alley cropping, forest, fallow and grazing land uses while shallow and nitrogen fixers are suitable for mixed cropping and continuously cultivated soil. It is advocated that farmers adopt good and efficient land use management systems for high carbon sequestration, soil fertility sustainability and climate change mitigation.

Key words: Agronomic, assessment, carbon sequestration, fertility status, land uses.