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Maize yield in China accounts for more than one-fourth of the global maize yield, but it is challenged by frequent extreme weather and increasing food demand. Accurate and timely estimation of maize yield is of great significance to crop management and food security. Commonly applied vegetation indexes (VIs) are mainly used in crop yield estimation as they can reflect the greenness of vegetation. However, the environmental pressures of crop growth and development are difficult to monitor and evaluate. Indexes for water content, pigment content, nutrient elements and biomass have been developed to indirectly explain the influencing factors of yield, with extant studies mainly assessing VIs, climate and water content factors. Only a few studies have attempted to systematically evaluate the sensitivity of these indexes. The sensitivity of the spectral indexes, combined indexes and climate factors and the effect of temporal aggregation data need to be evaluated. Thus, this study proposes a novel yield evaluation method for integrating multiple spectral indexes and temporal aggregation data. In particular, spectral indexes were calculated by integrating publicly available data (remote sensing images and climate data) from the Google Earth Engine platform, and county-level maize yields in China from 2015 to 2019 were estimated using a random forest model. Results showed that the normalized moisture difference index (NMDI) is the index most sensitive to yield estimation. Furthermore, the potential of adopting the combined indexes, especially NMDI_NDNI, was verified. Compared with the whole-growth period data and the eight-day time series, the vegetative growth period and the reproductive growth period data were more sensitive to yield estimation. The maize yield in China can be estimated by integrating multiple spectral indexes into the indexes for the vegetative and reproductive growth periods. The obtained R2 of maize yield estimation reached 0.8. This study can provide feature knowledge and references for index assessments for yield estimation research. [ABSTRACT FROM AUTHOR]

• Capacity of vegetation cover pattern to regulate runoff and soil erosion was focused on. • Capacity of vegetation cover to mitigate runoff and soil erosion is rainfall-dependent. • Soil loss was more readily to be regulated by spatial pattern of vegetation cover than runoff. Coupling vegetation cover pattern with soil erosion and runoff generation positions a multi-discipline hotspot. Due to the widely occurred patchy vegetation cover and water-limited environment, regulation of vegetation cover pattern on runoff and soil erosion in arid and semiarid environment was addressed widely. In tropical and subtropical environment, patchy vegetation cover pattern also widely occurred in human-dominated landscapes. However, the effect of vegetation cover pattern on runoff generation and sediment yield and its dependence on rainfall characteristics attract little attention, and are unclear. Correspondingly, this study addresses two relevant issues: (1) the rainfall-dependent capacity of vegetation cover pattern to mitigate runoff and soil erosion; (2) rainfall-runoff and rainfall-erosion regimes mitigated by vegetation cover pattern. Eighteen 10 m-by-5 m plots were constructed for the three-year (2015–2017) observation in a humid and red-soil-covered environment in southern China. The results show that vegetation cover pattern affected the response of runoff generation and soil erosion to rainfall. The soil loss was more readily to be regulated by the fraction and spatial pattern of vegetation cover than runoff; the potential of the fraction of vegetation cover in regulating soil loss positively response to rainfall depth and rainfall intensity; and rising rainfall depth led to a weakened relationship between vegetation coverage and runoff volume. Our results illustrated that the increased rainfall intensity promotes the regression relationship between vegetation coverage and runoff volume. In this humid environment, vegetation cover pattern regulates the response of runoff and sediment discharge to rainfall characteristics; and the effectiveness of vegetation cover pattern on regulation runoff and sediment discharge was rainfall-dependent. This study indicates that including connectivity parameters in quantifying the spatial pattern of vegetation may lead to different understanding of the effectiveness of vegetation cover on hydrology and soil erosion. [ABSTRACT FROM AUTHOR]

Improving the morphological structure of active materials is a reliable strategy for the fabrication of high-performance supercapacitor electrodes. In this study, we introduce a feasible approach to constructing the graphene/polypyrrole (PPy) composite film implanted onto the current collector through a two-step electrochemical deposition method utilizing MnO 2 as an intermediary template. The reduced graphene oxide (rGO) hydrogel film is first hydrothermally grown on a carbon cloth (CC) substrate to obtain a porous rGO@CC electrode on which MnO 2 is electrodeposited. Then the as-prepared rGO/MnO 2 @CC electrode is subjected to the electrochemical polymerization of pyrrole, with MnO 2 acting as an oxidizing template to facilitate the oxidative polymerization of pyrrole, ultimately yielding an rGO/PPy composite film on CC. The PPy synthesized via this methodology exhibits a distinctive interconnected structure, resulting in superior electrochemical performance compared with the electrode with PPy directly electrodeposited on rGO@CC. The optimized electrode achieves an impressive specific capacitance of 583.6 F g -1 at 1 A g -1 and retains 83% of its capacitance at 20 A g -1 , with a capacitance loss of only 9.5% after 5000 charge-discharge cycles. The corresponding all-solid-state supercapacitor could provide a high energy density of 22.5 Wh kg -1 and a power density of 4.6 kW kg -1 , with a capacitance retention of 82.7% after 5000 charge-discharge cycles. Furthermore, the device also demonstrates good flexibility performance upon bending at 90 and 180°. This work presents an innovative method for the preparation of carbon material/conducting polymer electrodes with specific structural characteristics and superior performance.