Biomass Effect on Soil Organic Carbon in Semi-Arid Continental Conditions in Central Turkey

Abstract

Organic carbon in soil represents plant, animal and microbial origin materials associated with mineral fractions in different phases of stabilization and decomposition. Following the combatting of desertification that lasted for almost 60 years in Karapinar District located in the Konya Closed Basin of central Turkey, this study was conducted to monitor the change in organic carbon dynamics of soil and vegetation in different land uses. The research revealed a relatively high ratio of soil organic carbon in preserved soils, but the average value was below 14.5 ton C/ha. This low value has a negative impact on many of the processes of maintaining soil quality.

Increasing the amount of organic matter will ensure that carbon dioxide, the leading greenhouse gas in the atmosphere, is held in soil. With this in mind, fallow, use of excess fertilizers of nitrogen and over-irrigation must be avoided, and legumes such as vetch and Hungarian vetch cultivation is recommended for maintaining the C/ N ratio in the semi-arid Karapinar region. For this reason, the current level of 4% forage crops production needs to be increased to 12% within more than 200.000 ha of cultivated land of Karapinar. While the natural pastures under preservation had the highest organic carbon content, the lowest values were obtained from overgrazed pastures. More than 120 natural plant species were identified during the species-count in the study area, which is an indication of the richness of the pastures in a semi-arid environment. Hence, it has been concluded that any grazing of more than 1.4 sheep per hectare would exceed the self-renewal process of plants, decrease organic input to soil and trigger desertification, which was halted following 60 years of protection.