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This paper focuses on county-level grain production and food security in North China; selects 17 indicators from both climatic conditions and human activities; applies yield fluctuation coefficients, spatial econometric modelling, the random forest method, and factor analysis to study the characteristics of grain production in North China and the influencing factors; and evaluates the situation of food security in North China based on grain production capacity. The following results were obtained: (1) The spatial and temporal changes in grain production located in North China from 2000 to 2020 are obvious. The grain output in North China from 2000 to 2020 maintains fluctuating growth at a rate of 0.38 × 1011 kg/10a. The east and south are the key areas for grain production in North China. Grain output was relatively stable except for 2003. with the cold spots of grain production being mainly in the northwestern area and the hot spots in the central and southern areas. (2) The changes in grain production in North China from 2000 to 2020 were less affected by climate and mainly influenced by human activity indicators. (3) As time progresses, the area of food shortage zones decreases in size, becoming evenly distributed and dispersed from the initial concentration in northern Hebei and most of Shanxi; the change in the supply–demand equilibrium zones is not obvious; and the area of surplus grain zones increases markedly in size, with a tendency to expand from the south and centre of the study area to the west and north. The grain production capacity of counties in the northwest and north is generally low, and even counties located in surplus grain areas have potential food security risks. However, in the east and south, due to their high grain production capacity, the per capita grain supply situation may be alleviated even in counties located in grain shortage areas. This study can deepen the understanding of the characteristics of food production in North China and enrich the research on food security. Analyses of factors influencing food production will improve a deeper understanding of food security. Food security evaluation based on food production capacity will contribute to a more precise and comprehensive understanding of the food security pattern in North China. [ABSTRACT FROM AUTHOR]

The urban ecological environment is crucial to the quality of life of residents and the sustainable development of the region, and the assessment and prediction of the ecological environment quality can provide a scientific guidance for ecological environment management and improvement. We proposed a novel approach to assess and simulate the urban ecological environment quality using the Geographic Information System Ecological Index (GISEI). First, we calculated the remote sensing ecological index (RSEI) for Xi'an in 2020. Second, we selected land use data, mean annual temperature, and mean annual relative humidity as ecological indicators. We regressed these indicators on the RSEI to obtain the GISEI of Xi'an in 2020. Finally, we simulated the GISEI of Xi'an in 2030 by predicting the ecological indicators and analyzed the changes in the ecological environment quality. The results of the study show that the ecological environment quality in Xi'an in 2020 is better overall. By 2030, most of the ecological environment quality in Xi'an will be worse, and the proportion of the excellent area will decrease from 42.8% to 3.8%. The more serious ecological degradation is mainly located in the regions bordering the Qinling Mountains and the Guanzhong Plain, and the ecological environment quality in most areas of the Qinling Mountains will deteriorate from excellent to good. [ABSTRACT FROM AUTHOR]

As eco–environmental effects have become important considerations in the construction and planning of production, living, and ecological spaces, we used a combination of quantitative and qualitative methods to analyze the eco–environmental effects' spatiotemporal evolution and present appropriate ideas for ecological restoration based on the land use data. The results show that during the research period both an improvement and degradation of the regional eco–environment occurred simultaneously. In the earlier period, the ecological environment tended to be worse, while in the later period, the eco–environmental quality was dramatically enhanced. Pasture ecological land in the study area had the strongest positive impact on the eco–environmental quality, while the negative effect of agricultural production land was severe. The quality of the regional eco−environment was enhanced (degraded) due to the extension (contraction) of ecological land. The construction of an ecological environment is a complex engineering task. Although the eco−environment in most areas of the study area showed an improving trend, the overall eco–environment remains relatively fragile. In the course of supporting high–quality regional social and economic growth and pursuing high–level environmental preservation strategies, we should take corresponding measures to protect and repair the regional ecological environment. [ABSTRACT FROM AUTHOR]

The Ms ≥8.0 strong earthquakes occurring in Chile since 1800 were analyzed using the ternary, quaternary, and quinary commensurability methods and the butterfly structure diagram, and it was believed that the earthquake signal in Chile in 2014 is relatively strong, a large earthquake is likely to occur in Chile in 2014. An analysis of spatial epicenter migrations showed that the longitudinal and latitudinal epicenter migrations have symmetry and synchronism, and there were five obvious northward migrations and four southward migrations. The symmetry axis of the longitudinal migrations is at about 71. 7° W and that of the latitudinal migrations is at about 30° S; these spatial symmetry axes are located at the subduction zone on the western margin of South America, where two major plates (the Nazca Plate and the South American Plate) converge.

Food security plays an important role in maintaining national stability and sustainable development of human society, and its research has become a hot issue at present. Shandong is the main grain producing area in China, and its grain production plays an important role in national food security. Accordingly, this paper is based on the county climate change, grain yield, sown area, fertilizer use, total power of rural machinery, and total population data in Shandong Province from 1995 to 2020. The evolution process of the food security pattern was studied by the methods of spatial analysis and comprehensive evaluation, the influencing factors of food security were quantitatively analyzed, and the adaptive countermeasures to alleviate the food security risks in this region were discussed. The results show that: Grain production increased by 30.62% from 1995 to 2020. The total population and per capita food availability also increased. Since 2000, more than a quarter of counties have experienced a high risk of food insecurity. The spatial agglomeration of grain production was enhanced, and the local agglomeration characteristics were significantly different. The average temperature in the growing season, the sown area, and the total power of agricultural machinery had a significant positive impact on grain production, while the annual average temperature had a significant negative impact on grain production. Improving the food supply system, strengthening the protection of cultivated land, improving the efficiency of fertilizer utilization, and increasing investment in agricultural science and technology can effectively alleviate food security risks. [ABSTRACT FROM AUTHOR]

Pine wilt disease is a devastating forest disaster caused by Bursaphelenchus xylophilus, which has brought inestimable economic losses to the world's forestry due to lack of effective prevention and control measures. In this paper, a porous structure CuBTC was designed to deliver avermectin (AM) and a control vector insect Japanese pine sawyer (JPS) of B. xylophilus, which can improve the biocompatibility, anti-photolysis and delivery efficacy of AM. The results illustrated the cumulative release of pH-dependent AM@CuBTC was up to 12 days (91.9%), and also effectively avoided photodegradation (pH 9.0, 120 h, retention 69.4%). From the traceable monitoring experiment, the AM@CuBTC easily penetrated the body wall of the JPS larvae and was transmitted to tissue cells though contact and diffusion. Furthermore, AM@CuBTC can effectively enhance the cytotoxicity and utilization of AM, which provides valuable research value for the application of typical plant-derived nerve agents in the prevention and control of forestry pests. AM@CuBTC as an environmentally friendly nanopesticide can efficiently deliver AM to the larval intestines where it is absorbed by the larvae. AM@CuBTC can be transmitted to the epidemic wood and dead wood at a low concentration (10 mg/L). [ABSTRACT FROM AUTHOR]

Temperature is one of the main factors affecting insect growth, development and reproduction. The effects of temperatures (10, 15, 20, 25 and 30°C) on the development and reproduction of Cinara cedri Mimeur (Hemiptera: Aphidoidea: Lachnidae) fed on Cedrus deodara (Roxb.) G. Don were evaluated in this study. With the increase of temperature from 10 to 30°C, the development duration at different development stages gradually shortened. There was a significant positive correlation between the developmental rates and temperature, following a quadratic regression model. The lower developmental threshold temperature (C) and effective accumulated temperatures (K) for completing a generation were 4.13°C and 263.4 degree-days, respectively. The highest fecundity was observed at 20°C with 25.74 first-instar nymphs/female. Both the highest intrinsic rate of increase (r, 0.11 ± 0.03) and net reproduction rate (R0, 19.06 ± 2.05) were observed at 20°C, whereas the lowest values of r (0.05 ± 0.01) at 10°C and R0 (5.78 ± 0.88) at 30°C were observed. The results suggest that temperature significantly affects the biology of C. cedri and the optimal temperature for its development is 20°C. [ABSTRACT FROM AUTHOR]

Sulfoxaflor, the first commercially available sulfoximine insecticide, has been used for the control of sap-feeding insect pests such as plant bugs and aphids on a variety of crops. However, its sublethal effects on the mirid bug Apolygus lucorum, one of the key insect pests of Bt cotton and fruit trees in China, have not been fully examined. Here, we evaluated the demography and feeding behaviour of A. lucorum exposed to sulfoxaflor. The leaf-dipping bioassay showed that the LC10 and LC30 of sulfoxaflor against 3rd-instar nymphs of this insect were 1.23 and 8.37 mg L-1, respectively. The LC10 significantly extended the nymphal duration and decreased the oviposition period by 5.29 days and female fecundity by 56.99% in the parent generation (F0). The longer duration of egg, 5th-instar nymphs, preadult, and male adult longevity were observed in the F1 generation (F1) at LC10. At the LC30, the duration of egg and 1st-instar nymph, female adult longevity, and oviposition period of the F1 were significantly shorter, while the nymphal duration in the F0 and duration of 5th-instar nymphs, preadult survival rate, and male adult longevity in the F1 significantly increased. The net reproductive rate (R0), intrinsic rate of increase (r), and finite rate of increase (λ) in the F1 were not significantly affected by these two concentrations, whereas the mean generation time (T) was lower at the LC30. Additionally, the probe counts and cells mixture feeding time were markedly lengthened by the LC10 and LC30, respectively, when A. lucorum nymphs exposed to sulfoxaflor fed on Bt cotton plants without insecticides. These results clearly indicate that sulfoxaflor causes sublethal effects on A. lucorum and the transgenerational effects depend on the tested concentrations. [ABSTRACT FROM AUTHOR]

Suffering from the double blow of the new crown pneumonia epidemic and floods, food security issues have once again become a source of concern. Eastern Gansu is an important dry farming area in northwestern China, and agricultural production has been greatly affected by climate change. Based on the climate data of 17 national meteorological stations in eastern Gansu from 1961 to 2020 and the data on population, grain planting area and grain production in each region from 1986 to 2019, using the Thornthwaite Memorial model, this paper analyzed the climate production potential (TSPV), population carrying capacity and population carrying capacity index in eastern Gansu, and then revealed the relationship between population and food in eastern Gansu. The findings and results revealed that: (1) over the past 60 years, the temperature in eastern Gansu has been increasing and precipitation has been decreasing; (2) TSPV has been increasing. Moreoever, the spatial distribution was significantly different, showing a trend of decreasing from the southeast to the northwest. Lintao, Huining, and Jingtai displayed a decreasing trend, while other areas exhibited an increasing trend. Precipitation was the main limiting factor for TSPV; (3) Grain production continued to increase due to changing hydrothermal conditions and improved production efficiency. Cultivated land–population carrying capacity and climate production potential–population carrying capacity (TSPV–population carrying capacity) both exhibited a significant increasing trend (p < 0.01). Cultivated land–population capacity increased from southeast to northwest, and all stations expressed an increasing trend. TSPV–population carrying capacity increased from southeast to northwest, and the whole region displayed an increasing trend. Even in extremely reduced production years, TSPV–population carrying capacity was also greater than cultivated land–population carrying capacity. This revealed that, under ideal conditions, TSPV–population carrying capacity can fully meet the needs of the current population. (4) The population carrying capacity index showed a significant downward trend (p < 0.01). It showed a trend of decreasing from south to north, and whole area underwent a decreasing trend consistently, indicating that the population–food relationship in eastern Gansu tended to be balanced. This result was conducive to correct assessment of the relationship between people and food in the study area, and provided a reference for formulating food policies. [ABSTRACT FROM AUTHOR]

With global warming, the frequency of drought in China is gradually increasing. The study of drought characteristics and its impact on crop yield is of great significance to ecological construction and food security. Based on the SPEI index in Xinjiang from 1961 to 2020, the changing characteristics of drought and their responses to meteorological yield of three kinds of crops (cotton, wheat and corn) were analyzed. The results revealed that the SPEI in Xinjiang exhibited a decreasing trend. Drought occurred less during 1961–1996 and mainly occurred during 1997–2020. The annual variation trend of SPEI decreased regionally, and the arid trend increased from northwest to southeast. The seasonal variation in SPEI displayed an increasing trend only in winter, but a decreasing trend in spring, summer and autumn. The decreasing trend of the SPEI index in spring accounted for 90.91%, mainly distributed in the central and eastern part of Xinjiang; the decreasing trend in summer accounted for 81.82%, mainly located in the eastern part of Xinjiang; the decreasing trend in autumn accounted for 84.85%, mainly located in the south and central and eastern part of Xinjiang; the decreasing trend in winter accounted for only 33.33%, mainly located in the southwest, central and eastern part of Xinjiang; the per unit area yield of the three kinds of crops showed a significant increasing trend (p < 0.01). The meteorological yield of cotton showed an increasing trend, while that of wheat and corn showed a decreasing trend. Correlation analysis of climatic yield and SPEI, and regression analysis of standardized climatic yield residuals and SPEI in different seasons revealed that drought in spring and autumn had the greatest effect on the meteorological yield of cotton, while drought in spring and summer had the greatest effect on the meteorological yield of wheat and corn. [ABSTRACT FROM AUTHOR]

Simple Summary: Myzus persicae is a worldwide pest causing significant economic loss, especially to vegetables. However, the mainly applied insecticides were not effective, whilst also endangering the safety of pollinators. Harmonia axyridis and Aphidoletes aphidimyza are predators of aphids, but they are costly and affected by temperature and insecticides. We conducted toxicity tests and greenhouse trails to make an effective combination of neonicotinoid insecticides and predators. Both H. axyridis and A. aphidimyza effectively controlled aphids whether combined with thiacloprid or not, at above 20 °C temperature condition. Our results indicated that it is it is necessary to choose H. axyridis or A. aphidimyza to control aphids based on economic and thermal considerations. Practically, thiacloprid could be used either as an emergency option to control aphids' abundance alone or in combination with natural enemies. Excessive insecticide application has posed a threat to pollinators and has also increased insecticide resistance of Myzus persicae Sulzer. Therefore, it is urgent to develop an economical and effective strategy, especially for greenhouse vegetables. Firstly, we selected a neonicotinoid insecticide that is specifically fatal to M. persicae but relatively safe to predators and bumblebees by laboratory toxicity tests and risk assessments. Then, we tested the effectiveness of the neonicotinoid insecticide under different temperature conditions. According to the LC50 values and the hazard quotients, thiacloprid met the requirements. Greenhouse trails indicated that thiacloprid was quite efficient, while control dropped to 80% without the application of thiacloprid. As for biological control, Harmonia axyridis effectively controlled 90% of aphids with thiacloprid or not. However, Aphidoletes aphidimyza performed better above 20 °C. Our results indicated that it is cost-effective to control M. persicae with A. aphidimyza in suitable temperature conditions and H. axyridis was more effective at low temperatures. Practically, thiacloprid could be used either as an emergency option to control aphids' abundance alone or in combination with natural enemies. [ABSTRACT FROM AUTHOR]