Soil soluble organic carbon and nitrogen pools under mono- and mixed species forest ecosystems in subtropical China

Abstract

Purpose The objective of the present study was to assess the differences in soil total C and N, microbial biomass C and N, soil soluble organic C and N among eight monoand mixed species forest ecosystems (18-year-old restoration) in subtropical China. Materials and methods Soil samples were taken at the 0-10 and 10-20-cm depths from each of the eight forest ecosystems: Masson pine (CP1); Pitch pine (CP2); mixed Slash pine and Sweetgum (CBMP1); mixed Slash pine and Camphortree (CBMP2); mixed Masson pine, Sweetgum, and Chinese Gugertree (CBMP3); mixed Sweetgum and Chinese Gugertree (BMP); Chinese Gugertree (BP1); and Sweetgum (BP2). Soil soluble organic C and N pools were measured using hot water and KCl extraction methods. Microbial biomass C (MBC) and N (MBN) were measured by fumigation-extraction method. Soil total C and N were determined using an isotope ratio mass spectrometer. Results and discussion Concentrations of soil soluble organic N (SON) extracted by KCl solution (35.1-116.9 and 11.2-78.2 mg kg -1 ) were greater than those by hot water (20.7-72.8 and 8.4-30.6 mg kg -1 ) in the 0-10 and 10-20-cm soils, while concentrations of soluble organic C (SOC) extracted by KCl solution were lower than those extracted by hot water in the 0-10 cm. Soil soluble C and N pools extracted by both hot water and KCl solution and the MBC and MBN were greatest under the broadleaf forest ecosystems, followed by the mixed conifer-broadleaf forest ecosystems, and then the conifer forest ecosystems. Conclusions Different restored forest ecosystems had significant impacts on soil SOC and SON, and MBC and MBN. The broadleaf forest ecosystems could be a better choice for the restoration of red soil chemical and biological prosperities than the conifer-broadleaf forest ecosystem and coniferous forest ecosystems. A further study is necessary to sample over seasons in order to understand whether the significant impacts on soil properties are related to the sample time. In addition, soil microbial community composition and microbial activity should be measured in such studies to understand mechanisms involved in the dynamics of soil SOC and SON pools.

Effects of single and mixed species forest ecosystems on diversity and function of soil microbial community in subtropical China

“…This suggested that soils under broadleaf forest plantations were less stressful and in the better status for restoration of the productivity and function of the eroded red soil. It was in accordance with the result that the broadleaf forest ecosystems could be a better choice for the restoration of L-(+)-Arabinose red soil chemical and biological prosperities than the conifer-broadleaf forest ecosystems and coniferous forest ecosystems (Jiang et al 2010a).…”

“…This confirms the role of the C substrate quality in determining C utilization (Paul and Clark 1989). This is explained that, at the same experimental sites, soil soluble C and N pools extracted by both hot water and KCl solution and the MBC and MBN were the greatest under the broadleaf forest ecosystems, followed by the mixed conifer-broadleaf forest ecosystems, and then the conifer forest ecosystems (Jiang et al 2010a). …”

Soil microbial properties under different vegetation types on Mountain Han

“…The elevation of SWC increased bacterial biomass [51] while weakening fungal biomass [20]. Needles decompose slowly, leading to a thicker humus layers under conifer vegetation than broadleaf, which may have been a barrier to precipitation into soil and eventually lowered SWC in topsoil under conifer [52,53].…”

Warming and grazing affect soil labile carbon and nitrogen pools differently in an alpine meadow of the Qinghai–Tibet Plateau in China

“…Relative small changes in the sizes and distribution of soil C and N pools may therefore induce substantial effects on atmospheric greenhouse gas concentrations and on global C and N cycling at large (Belay-Tedla et al 2009;Xu and Chen 2006). Such alterations in labile and less labile C and N pools may not only lead to new dynamic processes in the short term but can also influence the long-term terrestrial C and N storage and consequently feedback to the atmosphere Burton et al 2010;Jiang et al 2010;Xing et al 2010). Studies have also demonstrated that labile C and N pools in some situations could be sensitive to alterations in soil moisture, temperature and plant community structure resulting from climate change (Zak et al 1993;Xu et al 2009).…”