Effect of plantation on soil quality indicators and carbon sequestration in Safrabasteh Poplar Research Station in Guilan province

Abstract

Vegetation has a major impact on carbon sequestration and soil quality. In order to assess the effect of vegetation type on soil attributes, two different plantation of pure Bald Cypress (Taxodium distichum) and mixed Alder (Alnus subcordata) with Poplar (Populus deltoides) were selected in Safrabasteh Poplar Research Station, Guilan province. In each site morphological, physical and chemical soil properties were studied and compared with each other. The results showed that wet aggregate stability measured as mean weight diameter, bulk density and saturated hydraulic conductivity were significantly different between the two sites. The wet aggregate stability and soil hydraulic conductivity were significantly higher in soil of bald cypress stand compared to soil of alder and poplar stand. The soil with bald cypress stand had more organic carbon and lower bulk density compared to the soil with alder and poplar stand. The organic carbon content had a positive correlation with size of aggregates and a negative correlation with CaCO3 content of soils. The highest concentration of carbon was measured for aggregates with diameter greater than 6 mm. In contrast, aggregates with diameter of 0.25-0.6 mm had the highest concentration of CaCO3. The organic carbon contents of organic and mineral layers for soil with poplar and alder stand were 112.5 and 85.73 ton/ha and for soil with bald cypress stand were 123.08 and 102.97 ton/ha, respectively. The findings of this research indicate that vegetation cover has major impact on carbon sequestration and thereby controls quality indicators of soils. Bald cypress accumulated significantly more organic carbon in soil compared to the mixed alder and poplar stand.

Keywords

• soil quality properties
• carbon sequestration
• mean weight diameter