TOTAL AND HOT-WATER EXTRACTABLE CARBON RELATIONSHIP IN CHERNOZEM SOIL UNDER DIFFERENT CROPPING SYSTEMS AND LAND USE

Abstract

A study was conducted to determine the hot water extractable organic carbon (HWOC) in 9 arable and 3 non arable soil samples on Haplic Chernozem. The hot water extractable carbon represents assimilative component of the total organic matter (OM) that could contain readily available nutrients for plant growth. The obtained fraction of organic carbon (C) makes up only a small percentage of the soil OM and directly reflects the changes in the rhizosphere. This labile fraction of the organic matter was separated by hot water extraction at 80°C. In our study the HWOC content in different samples ranged from 125 mg g-1 to 226 mg g-1. On the plots that are under native vegetation, higher values were determined (316 mg g-1 to 388 mg g-1). Whereas samples from arable soils were lower in HWOC. It was found that this extraction method can be successfully used to explain the dynamics of the soil OM. Soil samples with lower content of the total OM had lower HWOC content, indicating that the preservation of the OM depends on the renewal of its labile fractions.

Keywords

• organic matter
• hot water extractable carbon
• chernozem
• cropping