TILLAGE EFFECTS ON SOIL ORGANIC CARBON, MICROBIAL BIOMASS CARBON AND BETA-GLUCOSIDASE ENZYME ACTIVITY IN A TYPIC HAPLOXERERT SOIL

Biological indicators allow to define early changes in soil environment due to the impacts in land management over time. This study investigated the effects of long-term (2006-2015) two conventional (CT-1 and CT-2), three reduced (RT-1, RT-2 and RT-3) and a no-till (NT) on soil organic carbon (SOC), microbial biomass carbon (MBC) and beta-glucosidase enzyme activity (BGA) in eastern Mediterranean region, Turkey. Experimental design was randomized complete block with three replications. Results indicated that SOC, MBC and BGA significantly differed among tillage treatments. Non-disturbed soils under NT had nearly 75% higher SOC (8.80 gkg(-1)), 359% higher BGA (207.66 mg PNP kg(-1)h(-1)) and 68% higher MBC (185.9 mg C kg(-1) soil) compared with highly disturbed soils under CT-1 system. The BGA and MBC concentrations under NT were also significantly higher than the three RT treatments. In contrast to BGA and MBC, the SOC contents under RT systems did not differ from that of NT treatment. Higher concentrations of BGA and MBC under NT and partially under RT compared to CT treatments were most likely related to the increased organic matter contents and non-disturbed environmental conditions.