Organic matter sequestration under sugarcane cultivation in Nagari Lawang, a wet tropical region, West Sumatra Indonesia

Organic matter sequestration in soil is important not only to improve soil properties but also to avoid environmental problems such as global warming due to high carbonic gases in the atmosphere. This research was aimed to calculate the amount and rate of OM sequestration under sugarcane cultivation. The soil was sampled at 4 ages of sugarcane cultivation (±15, ±50, ±80, and ±100 Y) from a 1-m soil profile and from forest as a comparison. The results showed that the SOM was higher by longer cultivation of the sugarcane. Compared to the forest nearby, the amount of SOM stock under sugarcane reached 0.88, 0.77, 0.95, and 0.99 respectively, for the sugarcane 15, 50, 80, and 100 years’ old. Within 1-m soil profile, the SOM stock under forest (412.68 T/Ha) was >100 years (409.28 T/Ha) >80 years (390.02 T/Ha) >15 years (361.45T/Ha) >50 years (319.55 T/Ha) of sugarcane cultivation. The OM sequestration rate for the 1-m soil profile under sugarcane cultivation was -0.40 T/Ha/Y (between 15-50 Y), 0.78 T/Ha/Y (between 50-80 Y) and 0.32 T/Ha/Y (between 80-100 Y). This implies that traditional sugarcane cultivation can avoid soil degradation as well as decrease the CO2 emission to the atmosphere causing global warming.