We investigated characteristics (scales and composition) of soil seed banks at eight study sites in the rocky mountain region of Beijing by seed identification and germination monitoring. We also surveyed the vegetation communities at the eight study sites to explore the role of soil seed banks in vegetation restoration. The storage capacity of soil seed banks at the eight sites ranked from 766.26 to 2461.92 seeds·m -2 . A total of 23 plant species were found in soil seed banks, of which 63 80% of seeds were herbs in various soil layers and 60% of seeds were located in the soil layer at 0 5cm depth. Biodiversity indices indicated clear differences in species diversity of soil seed banks among different plant communities. The species composition of aboveground vegetation showed low similarity with that based on soil seed banks. In the above- ground plant community, the afforestation tree species showed high importance values. The plant species originating from soil seed banks represented natural regeneration, which also showed relatively high importance values. This study suggests that in the rocky mountain region of Beijing the soil seed banks played a key role in the transformation from pure plantation forest to near-natural forest, promoting natural ecological processes, and the role of the seed banks in vegetation restoration was important to the improvement of ecological restoration methods. 相似文献
Autumn‐sown winter‐type faba bean (Vicia faba L.) has been shown to have a yield advantage over spring sowing. Still, adoption of this overwintered pulse crop remains limited in temperate locations, due to inadequate winter hardiness. This research sought to understand how the prevailing temperature during emergence and seedling development, that is pre‐acclimation, influences freezing tolerance. Seedlings grown under a controlled “warm” 17/12°C (day/night) pre‐acclimation environment were initially less freezing tolerant than those grown under a “cold” 12/5°C temperature treatment. Stem and particularly root tissues were primarily responsible for slower cold acclimation, and there was a genotype specific response of above‐ground tissues to pre‐acclimation treatment. Both above and below‐ground tissues should be tested across a range of pre‐acclimation temperatures when screening faba bean germplasm for freezing tolerance. 相似文献
The effectiveness of co-feeding loach ( Misgurnus anguillicaudatus ) larvae with live and microparticle diets on weaning performance was described here. Dry weight, total length, length and weight-specific growth rate (SGR) and survivals were monitored at 23–25 °C from the 4th day post hatching (dph) in different diet regimes, which included: microparticle diets (A), live cladocerans (B), enriched cladocerans (C), half microparticle diets plus half live cladocerans (D) and half microparticle diets plus half enriched cladocerans (E). The SGR (L and W) were significantly lower in treatment A than in other treatments after completing metamorphosis (day 4–20, P <0.05). On 30 dph, dry weight (mg) and total length (mm) were significantly lower in treatment A than in other treatments ( P <0.05). There were no significant differences in growth in treatments B, C, D and E before 30 dph. However, when live feed was withdrawn from 31–60 dph, in metamorphosed fish, there were significant differences ( P <0.05) among the treatments in survival and growth. Metamorphosed fish in treatment E had higher survival than the fish in other treatments at the end of the experiment. The SGR (L and W) of weaned fish in treatments B and C were similar but lower than in treatments A, D and E respectively. However, dry weight and total length in treatment A were significantly lower than in treatments D and E. It is suggested that weaning of M. anguillicaudatus from early development would appear to be feasible and that larval co-feeding improves the growth and the survival. 相似文献
Biochar addition can expand soil organic carbon (SOC) stock and has potential ability in mitigating climate change. Also, some incubation experiments have shown that biochar can increase soil inorganic carbon (SIC) contents. However, there is no direct evidence for this from the field experiment. In order to make up the sparseness of available data resulting from the long‐term effect of biochar amendment on soil carbon fractions, here we detected the contents and stocks of the bulk SIC and SOC fractions based on a 10‐year field experiment of consecutive biochar application in Shandong Province, China. There are three biochar treatments as no‐biochar (control), and biochar application at 4.5 Mg ha?1 year?1 (B4.5) and 9.0 Mg ha?1 year?1 (B9.0), respectively. The results showed that biochar application significantly enhanced SIC content (3.2%–24.3%), >53 μm particulate organic carbon content (POC, 38.2%–166.2%) and total soil organic carbon content (15.8%–82.2%), compared with the no‐biochar control. However, <53 μm silt–clay‐associated organic carbon (SCOC) content was significantly decreased (14%–27%) under the B9.0 treatment. Our study provides the direct field evidence that SIC contributed to carbon sequestration after the biochar application, and indicates that the applied biochar was allocated mainly in POC fraction. Further, the decreased SCOC and increased microbial biomass carbon contents observed in field suggest that the biochar application might exert a positive priming effect on native soil organic carbon. 相似文献
Biochars produced from different feedstocks (such as wood, pig manure) possess varying physical and chemical properties, which have influence on crack and evaporation rate of biochar-amended soil (BAS). Furthermore, influence of compaction state and drying-wetting cycles on evaporation rate and cracking of BAS has not been investigated comprehensively. The objective of this study was to investigate the effects of biochar types, compaction state of BAS, and drying-wetting cycles on crack propagation and retained water (or evaporation rate).
Material and methods
An animal and plant feedstock-based biochars were produced in-house from pig manure (PM) and wood (W), respectively. In addition, nano structured chalk and wheat biochar (CWB) were also produced. Soil amended with individual biochars was compacted in petri-glass discs at two densities. Disc specimens were subjected to multiple drying-wetting cycles, and evaporation rate of specimens and crack area were monitored throughout the experimental period (70 days). Images were captured after every 24 h and processed using image processing technique to obtain the crack intensity factor (CIF).
Results and discussion
The results show that plant-based W BAS showed the high water retention, i.e., low evaporation rate and low CIF. Furthermore, the crack potential of CW BAS was seen to be higher. In dense compacted soil, maximum CIF% can be reduced from 3.9 to 0.4% for W BAS, from 3.9 to 1.7% for PM BAS, and from 3.9 to 1.6% for CW BAS.
Conclusion
WB was able to resist cracking more efficiently than other types of biochar. Evaporation was found to be minimal for plant-based W BAS at 10% biochar percentage. Higher biochar content in soil was seen to increase the water retention of BAS significantly. Dense state of BAS at high biochar content (i.e., 10%) was effective in reducing evaporation rate and crack progression.
Journal of Soils and Sediments - Information related to spatial distribution and dominants of soil organic matter (SOM) is critical for evaluating soil quality and assessing the carbon... 相似文献