6 research outputs found

    Soil–Plant Indices Help Explain Legume Response to Crop Rotation in a Semiarid Environment

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    Crop productivity is typically affected by various soil–plant factors systematically as they influence plant photosynthesis, soil fertility, and root systems. However, little is known about how the productivity of legumes is related to crop rotation systems. The objectives of this study were to determine the effect of rotation systems on legume productivity and the relationships among legume productivity and soil–plant factors. Three annual legumes – chickpea (Cicer arietinum L.), pea (Pisum sativum L.), and lentil (Lens culinaris Medikus), were included in various diversified rotation systems and compared with legume monoculture in the 8-year rotation study. Soil N and water conditions, and canopy and root systems were evaluated at the end of 8-year rotation in the semiarid Canadian prairies. Results showed that diversified rotation systems improved leaf greenness by 4%, shoot biomass by 25%, nodule biomass by 44%, and seed yield by 95% for chickpea and pea, but such effects were not found for lentil. Pea monocultures increased root rot severity by threefold compared with diversified rotations, and chickpea monoculture increased shoot rot severity by 23%, root rot severity by 96% and nodule damage by 219%. However, all the legume monocultures improved soil N accumulation by an average 38% compared to diversified systems. Pea and chickpea displayed considerable sensitivity to plant biotic stresses, whereas lentil productivity had a larger dependence on initial soil N content. The 8-year study concludes that the rotational effect on legume productivity varies with legume species, the frequency of a legume appearing in the rotation, and the integration of relevant soil and plant indices

    Van der Waals Coupled Organic Molecules with Monolayer MoS<sub>2</sub> for Fast Response Photodetectors with Gate-Tunable Responsivity

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    As a direct-band-gap transition metal dichalcogenide (TMD), atomic thin MoS<sub>2</sub> has attracted extensive attention in photodetection, whereas the hitherto unsolved persistent photoconductance (PPC) from the ungoverned charge trapping in devices has severely hindered their employment. Herein, we demonstrate the realization of ultrafast photoresponse dynamics in monolayer MoS<sub>2</sub> by exploiting a charge transfer interface based on surface-assembled zinc phthalocyanine (ZnPc) molecules. The formed MoS<sub>2</sub>/ZnPc van der Waals interface is found to favorably suppress the PPC phenomenon in MoS<sub>2</sub> by instantly separating photogenerated holes toward the ZnPc molecules, away from the traps in MoS<sub>2</sub> and the dielectric interface. The derived MoS<sub>2</sub> detector then exhibits significantly improved photoresponse speed by more than 3 orders (from over 20 s to less than 8 ms for the decay) and a high responsivity of 430 A/W after Al<sub>2</sub>O<sub>3</sub> passivation. It is also demonstrated that the device could be further tailored to be 2–10-fold more sensitive without severely sacrificing the ultrafast response dynamics using gate modulation. The strategy presented here based on surface-assembled organic molecules may thus pave the way for realizing high-performance TMD-based photodetection with ultrafast speed and high sensitivity
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