Comparative Evaluation of Short Term Organic Carbon Sequestration under Different Nutrient Managements during Cropping Cycles on a Ferric Acrisol in Ghana

Abstract

There is scanty information on the short term effect of soil management practices on soil carbon sequestration during cropping cycles in the tropics. This study is a short term experiment conducted in 2006 and 2007 to evaluate the extent to which nutrient management strategies could impact soil carbon sequestration during cropping seasons in the short term. The study was conducted on a Ferric Acrisol in the semi-deciduous forest zone of Ghana and was laid in a split plot, arranged in a randomized complete block design with three replications. Management strategies such as poultry manure - PM (4 t/ha), chemical fertilizer (CF) - NPK 15-15-15 (90-60-60 kg/ha), complementary application of poultry manure and chemical fertilizer – PM + CF (45-30-30 kg/ha NPK + 2 /ha poultry manure) and a control (no amendment) were evaluated under selected cropping systems such as continuous maize (CM), maize/soybean (M/S) intercropping and maize cowpea (M/C) rotation. Soil samples were taken from treated plots at a depth of 0 – 15 cm and analyzed for soil organic carbon. Results indicated a significant (P < 0.05) build up of soil organic carbon under PM + CF and CM system from 2006-major season to 2007 –major season. The PM + CF recorded soil organic carbon (SOC) values of 1.18 – 1.31% from 2006 -major to 2007- major season which indicated that 0.13 % carbon was sequestered within the short period. Continuous maize cropping system recorded an increase in SOC from 1.19 % in 2006 – major season to 1.31 % in 2007- major season. Crop residues under PM + CF and PM managements sequestered the highest carbon values of 49.05 and 49.11% respectively. The implication is that crops under PM + CF and PM amendments can serve as good carbon sinks to reduce global warming and at the same time produce higher soil organic carbon which can enhance high soil productivity especially on low nutrient status soils