Interactions on mixing litters from beneath Sitka spruce and Scots pine and the effects on microbial activity and N-mineralization
1991
Williams, B.L. | Alexander, C.E.
Columns packed with loose needle litters from pure Sitka spruce (SS), Scots pine (SP) and a 1:1 mixture (SS & SP) were leached for 21 weeks with distilled water. At the start the SP litter had smaller microbial biomass C and N contents, but a significantly (P < 0.001) greater content of fluorescein diacetate active hyphae than that of SS. Enchytraeid worms, present on SS, but not SP litter, proliferated during the experiment and numbers were significantly (P < 0.01) greater in SS & SP than SS or SP. Carbon dioxide was evolved at a significantly greater rate from SS than SP, whereas SS & SP had the same respiratory activity as pure SS. Mineral N accounted for 28, 24 and 8% of the total-N in SS, SS & SP and SP, respectively. Approximately 50% of the mineral-N in SS and SS & SP was NO3(-) but in SP only 4% was present as NO3(-). The increased C and N mineralizing activities in SS & SP compared with the calculated values for a 1:1 mixture of SS and SP were attributed to an interaction between enchytraeid worms in SS and a dominantly fungal biomass in SP litter. This effect was observed on mixing litters from two separate sites and it remains to be shown that pine and spruce litter from the same site interact in the same way.
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