Comparison of carbon sequestration potential of soybean (Glycine max (L.) Merill) in two conventional and conservation cropping systems (Case study: Gorgan city)

Carbon sequestration in plant organs is one of the most important ways to reduce atmospheric CO2 and also to reduce greenhouse effect and climate change. In order to investigate the effect of conventional and conservation cropping systems on carbon sequestration potential in soybean plant organs as an ecosystem service, a study was conducted in agricultural lands of Gorgan city during 2014-15.

In this study, 48 soybean fields were selected in the main directions of Gorgan city and sampling was carried out using W method during physiological ripe (late November). An electric burn furnace method was used to determine the amount of stored carbon. The stored carbon content was determined individually in soybean organs including root, stem, leaf, pod and seed. The weight of each plant organ was estimated per unit area, then using the carbon sequestration coefficient, the total amounts of carbon sequestration per unit area was obtained.

The average amount of carbon in soybean plant was estimated as 3281.4 kg/ha under the conventional cropping system and 3176.1 kg/ha under conservation cropping system. The reason for this result was the higher yield of plant biomass in conventional cropping system. Similar results were found for plant organs, so that the average amount of carbon were 1181.6 and 1249.3 kg/h seed, 792.19 and 710.27 kg/ha in leaves, 968.61 and 888.85 kg/ha in stem, 69.20 and 87.12 kg/ha in pods and 269.81 and 249.57 kg/ha in roots under conventional and conservation cropping systems, respectively. Results showed that there was a significant different between the amounts of carbon sequestration in the above ground and below ground organs of soybean. The carbon sequestration amounts were about 2993.8 kg/ha in above ground organs and about 265.59 kg/ha in the below ground organs.

In this study, it has been found that the potential of carbon sequestration in soybean plant organs is similar in conventional plant system and conservation farming system. Results showed that there was a significant different between the amounts of carbon sequestration in the above ground and below ground organs of soybean. The carbon sequestration amounts were about 2993.8 kg/ha in above ground organs and about 265.59 kg/ha in the below ground organs.

In this study, it has been found that the potential of carbon sequestration in soybean plant organs is similar in conventional plant system and conservation farming system. Keywords: Soybean, Conservation cropping system, Carbon Sequestration, Plant organs