Abstract

Plantation development stage (forest age sequence) influences environmental conditions and litter inputs, which can modify labile C and N pools. Changes in labile C and N pools during stand development could vary considerably with soil parent material. However, empirical evidence is scarce regarding the extent of interactive effects between parent material and stand development stage on labile C and N pools in plantations of Chinese fir (Cunninghamia lanceolata (Lamb.) Hook.), the dominant plantation tree in southern China. We examined the concentrations of soil labile C and N (dissolved organic carbon, DOC, dissolved organic nitrogen, DON, dissolved inorganic nitrogen, DIN, microbial biomass carbon, C-mic, microbial biomass nitrogen, N-mic) and basic soil properties within a soil depth of 100 cm for three stand development stages (young, middle-aged and mature) of Chinese fir plantations grown on soils derived from granite or siltstone. The parent material influenced the responses of the DON, DIN and N-mic pools to stand development stage, whereas no interaction effect of parent material and stand on the C-mic and DOC pools was observed. The parent material had a clear effect on the standing pools of labile C and N. Siltstone soils tended to have greater pool sizes of DOC, DON, DIN, and N-mic and greater ratios of C-mic/total carbon (TC) and N-mic/total nitrogen (TN). The stand development stage did not affect the DOC, C-mic and C-mic/TC ratio. The mineral N and N-mic pools increased significantly and the DON and DON/TN ratio declined sharply from young to middle-aged stands in both soil type. The changes in the DON, DIN and N-mic pools and the N-mic/TN ratio from middle-aged to mature stands depend on the parent material. The concentrations of DOC, DON, DIN, C-mic and N-mic were positively correlated with multiple soil parameters, such as the TC, TN, C/N ratio, water-stable aggregates (WSA), and water content, but negatively correlated with the bulk density (BD). DOC, DON, C-mic and N-mic significantly decreased with soil depth, but the extent of the decrease in DOC and DON was greater in course-textured granite soils. Overall, the turnover rates of the labile C pools are higher in the siltstone soils where internal N cycling during a traditional rotation similar to 25 years maintain the supply of mineral N and improve N incorporation into microbial biomass. These results highlight the need to identify soil physicochemical properties before afforestation. The rotation length and N fertilizer application in Chinese fir plantations should be adjusted based on the soil parent material.

Keywords

Bedrock; Stand age; Nutrient cycling; Labile C turnover; Forest management practices

Published in

Geoderma
2019, Volume: 338, pages: 247-258
Publisher: ELSEVIER SCIENCE BV

SLU Authors

• Tigabu, Mulualem

  • Southern Swedish Forest Research Centre, Swedish University of Agricultural Sciences
    
  • Fujian Agriculture and Forestry University

Sustainable Development Goals

SDG15 Protect, restore and promote sustainable use of terrestrial ecosystems, sustainably manage forests, combat desertification, and halt and reverse land degradation and halt biodiversity loss


UKÄ Subject classification

Soil Science
Environmental Sciences related to Agriculture and Land-use


Publication identifier

DOI: https://doi.org/10.1016/j.geoderma.2018.11.050

Permanent link to this page (URI)

https://res.slu.se/id/publ/99009