Short-term bioavailability of carbon in soil organic matter fractions of different particle sizes and densities in grassland ecosystems.

摘要: The quality, stability and availability of organic carbon (OC) in soil matter (SOM) can vary widely between differently managed ecosystems. Several approaches have been developed for isolating SOM fractions to examine their ecological roles, but links the bioavailability OC size-density microbial communities not previously explored. Thus, presented laboratory study we investigated potential structure associated different particle-size density SOM. For this used samples from four grassland ecosystems with contrasting management intensity regimes two types: a Haplic Cambisol typical Chernozem. A combined fractionation protocol was applied separate clay-associated (CF1, <1 μm; CF2, 1-2 μm) light (LF1, <1.8 g cm(-3); LF2, 1.8-2.0 cm(-3)). These were as sources respiration experiment determine bioavailability. Measured CO2-release an index substrate accessibility linked community structure, determined by phospholipid fatty acids (PLFA) analysis. key factors controlling decomposition processes, thus OC, identified: plant composition grasslands (both which affect chemical turnover OC) specific properties individual fractions. PLFA patterns highlighted differences examined grasslands, fractions, providing first broad insights into active communities. From observed interactions abiotic biotic affecting demonstrate that increasing could enhance only intermediate pools, also passive pool.