Depletion of soil nutrients is a major cause of decline in productivity of forest plantations in successive rotations. Biochar amendment in agricultural systems has been shown to yield various beneficial effects, including increasing soil phosphorus (P) availability. However, the direct and indirect effects of biochar addition on forest soil P dynamics have largely been unexplored. The objective of this study was to examine how biochar produced from harvest residue (leaves and woodchips) affect the P dynamics in second rotation Cunninghamia lanceolata (Chinese fir) plantation soil. An incubation experiment which involved mixing of forest soil with 1% or 3% w/w leaf or woodchip biochar, pyrolyzed at 300 °C or 600 °C, was conducted for 80 days at 20 °C. After 7, 40 and 80 days of incubation, soil samples were analyzed for total and available P, inorganic and organic P pools, and soil phosphatase activity. At the end of the incubation period, bacterial community composition and diversity were analyzed by 16S rDNA sequencing. The leaf biochar produced at both pyrolysis temperatures was more alkaline and had significantly higher soluble P, nitrogen and calcium contents than the woodchip biochar. Soil total and available P increased significantly in all leaf biochar treatments after 80 days incubation compared to the untreated control soil, but the woodchip biochar treatments had no significant effects.
Purpose: This study investigates how online user intention in searching health information is affected by problematic situations.Design/methodology/approach: Based on the Theory of Reasoned Action, the Technology Acceptance Model, and Sense-making theory, we propose two dimensions of problematic situations: urgency and severity of health issues being searched online. Data were collected through a questionnaire survey among 214 Wuhan University students and analyzed using hierarchical regression analysis.Findings: Perceived usefulness, perceived ease of use, and subjective norm can influence user intention to seek health information online. The urgency of problematic situations has a negative moderating effect on the relationship between perceived ease of use and user intention and the relationship between subjective norm and user intention. The severity of problematic situations has a negative moderating effect on the relationship between subjective norm and user intention.
Research limitations:The respondents of the survey are limited to students in one Chinese university, so whether this study's results can be applied to another population or not remains to be verified. In addition, only two dimensions of problematic situations are considered in this study.
Practical implications:The paper puts forward the moderating effect of problematic situations and verifies it, which is the compensation for online health information-seeking behavior research. Besides, our analyses have implications for professional design of health care systems and related consumer information searches, and improve their performance.Originality/value: Previous work has reported the effects of problematic situation on user intention to seek health information online, ignoring its influence on other factors. This empirical study extends that work to identify the influence of problematic situation when seeking intention-behavior data in two dimensions, urgency and severity.
Slow plant growth, low biomass, and low bioavailability of heavy metals in soil are important factors that limit remediation efficiencies. This study adopted a pot cultivation method to evaluate the phytoremediation efficiency of Neyraudia reynaudiana, planted in contaminated soil from a lead-zinc mining area. The soil was inoculated with earthworms (Eisenia fetida), and mixed with the chelating agent ethylenediaminetetraacetic acid (EDTA) one month after planting. The addition of earthworms significantly increased the aboveground biomass of N. reynaudiana and activated heavy metals in the soil, thus facilitating heavy metal uptake by N. reynaudiana. The addition of EDTA significantly increased the incorporation and transport of heavy metals, reduced the uptake of heavy metals by the plant cell wall, and increased the proportions of cellular soluble constituents. Especially with regard to lead, inoculation with earthworms and EDTA application significantly promoted the accumulation efficiency of N. reynaudiana, increasing it 7.1-16.9-fold compared to the control treatment without earthworms and EDTA, and 1.5-2.3-fold compared to a treatment that only used EDTA.
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