Abstract

Composts have different potentials of sequestering carbon into underground soils. The present study assessed soil carbon sequestration potential of Tithonia diversifolia chimato composts (CC). CC was made by blending Tithonia diversifolia with maize stalks (Td/MS) as follows: 0:100, 20:80, 50:50, 60:40, 80:20 and 100:0. Soil treatments pots were arranged in fully randomized design in which a homogeneous mixture of 1.0 kg of CC and 4 kg of soil was placed in pots. 3 maize seeds were planted per pot and standard agronomical practices were followed till harvesting. Soil organic carbon was determined using standard methods before and after each cropping season. Maximum soil carbon retention was observed in treatments supplemented with chimato composts prepared using Td/MS ratios of 50:50 (89.1%) and 60:40 (92.3%) compared to those 0:100 (20%), 20:80 (23.2%) and 40:60 (10.9%) which experienced greatest soil organic carbon loss. Significant positive correlation was observed (r = 0.996; P < 0.05) between initial T. diversifolia used in making chimato composts and soil organic carbon retention wheras significant negative correlation was observed (r = 0.983) between the same with soil organic carbon losses. The observation is attributable to high levels of maturity and stability of CC prepared with Td/MS = 50:50 and Td/MS = 60:40 such that relatively significant stable C was being oxidized and decomposed to meet microbial and plant N requirements. Considerable nitrogen loss was observed in treatments with chimato composts prepared using Td/MS = 100:0 (58.9%) and Td/MS = 80:20 (47.7%) and maximum nitrogen was retained in supplemented with chimato composts prepared using Td/MS = 50:50 (59.1%) and Td/MS = 60:40 (42.3%). The results suggest CC with Td/MS ? 50:50 and Td/MS ? 60:50 have great potential of combating climate change through sequestration of huge quantities of carbon into underground soil.

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