Evaluation of the carbon sequestration potential by barley crop in saline soils (Case study: Gomishan county, Golestan province)

According to current reports, the main cause of global warming and climate change is the impact of greenhouse gases, especially carbon dioxide. Carbon sequestration in soil and plant biomass is the simplest and most economically viable solution to reduce the concentration of Co2 and atmospheric carbon. Due to interactions between the rate of carbon sequestration with crop management and soil characteristics especially salinity, the study of different management options can play an effective role in increasing carbon sequestration in lands with limitation. The purpose of this research was to evaluate the carbon sequestration of barley crop in the lands of Gomishan county (Golestan province) in two different sites with high EC (>12 dS/m) and low EC (< 12 dS/m).

To conduct this study, in first survey of field performed to determine the two mentioned areas in the fall of 2018. Then, 50 fields were selected as sampling sites that included as 25 samples from barley fields with high EC and 25 samples with low EC. Soil sampling was done before planting and after harvesting in barley fields. The amount of organic carbon accumulation in the soil resulting from the difference between these two sampling steps was considered as carbon sequestration. The combustion method was used to determine the amount of organic carbon in plant organs. Then, data of soil and plant carbon sequestration were entered into ArcMap software and these data were interpolated to the area according to different geostatistical methods and presented as thematic maps.

The results showed that the carbon sequestration potential by barley crop in the agricultural lands of southern of Gomishan county had the highest potential by 2369 kg/ha. Also, the amount of organic carbon in the above ground organs was estimated higher than the below ground organs due to its higher dry weight. The study of soil carbon sequestration in fields with EC >12 dS/m showed that barley crop played an effective role in regulating the decreasing trend of carbon sequestration in saline soils, which indicates the importance of barley crop in reducing soil salinity and resulted the carbon sequestration process changes.

In this study, results showed that carbon sequestration was negative in some barley fields. This result indicated that carbon emission is higher than carbon storage in soil during growing season. Therefore, the appropriate field management can affect on land quality improving, saline reducing and carbon sequestration increasing.