|Contributions||Open University. Biosystems, Energy and Environment Research Unit.|
|The Physical Object|
Biomass production and stability of bispecific mixtures were highly influenced by their species composition. For the same species at the same site, it has also been shown that mixture biomass production depended on the species involved due to differences in species competitive ability (Wendling et al., ). While facilitation effect were Cited by: 1. Water addition increased soil microbial biomass, but water reduction had no effect. • Species mixture decreased soil total and individual group microbial biomass. • Water reduction increased species mixture effects on soil microbial biomass. • Soil microbial biomass increased with the abundance of broadleaved trees. •Cited by: 2. A species’ biomass in monoculture was fairly predictive of its biomass in mixture, such that high-yielding species in monoculture were also high yielding in mixture . Species mixtures may increase the efficiency of water use; thus, reducing the investment required for roots (Canarini et al., ). Species mixture had no significant effect on litterfall biomass, which might be partly attributable to that both Populus tremuloides and Pinus banksiana are shade intolerant (Ma et al., ).
Average biomass yield ranged from to Mg ha −1 with the highest yielding treatments being grass monocultures or an eight species grass–legume mixture. An increase in species richness from one to eight species increased yield an average of 28%, but increasing species richness from 8 to 12 or 24 species had no yield advantage at most. Overall, mixtures produced equivalent or more biomass and N content as monoculture species. Environmental and cropping system factors affected relative productivity of mixtures. Mixtures performed better in coarse‐textured soils and following corn harvest. Biomass productivity is often obtained as a byproduct of a biomass study with a different primary objective. In biomass studies of second growth hardwood stands (Young ) and second growth softwood stands (unpublished) more than plots were established with all trees cut a few centimeters above ground and each plot the annual rings were counted on sample trees to determine . some minor species in the production of cross-laminated timber (Image: Edinburgh Napier University) potential for mixtures of downy birch and aspen as a woodfuel crop (Scott Wilson) Growing for biomass Forestry for biomass production.
Biomass production was measured for three years in perennial grasses grown as pure stands, in legume‐grass mixtures, and legume‐grass‐forb mixtures across a species richness gradient. In unfertilized species‐rich mixtures, average biomass yields per experimental site and year were in the range from 3 to 9 metric ton DM ha −1 yr −1. Future studies should examine changes in biomass production for mixture composition with time for selection of optimal regional specific species mixtures. Perennial biofuel crops help to reduce both dependence on fossil fuels and greenhouse gas emissions while utilizing nutrients more efficiently compared to annual crops. In this exploratory study, we show how combining the strength of tree diversity experiment with the long-term perspective offered by forest gap models allows testing the mixture yielding behavior across a full rotation period. Our results on a SW France example illustrate how mixing maritime pine with birch may produce an overyielding (i.e., a positive net biodiversity effect). Understanding. of phenological diversity to increase biomass production are limited, as studies explicitly testing productivity benefits from mixtures have focused on spring-sown mixtures (Wortman et al., ; Smith et al., ). Fall sown mixtures provide the opportunity to enhance biomass production .