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【Objective】 Global warming is expected to increase the frequency of extreme weather events such as floods and droughts; understanding their statistical characteristics is important for developing mitigation strategies. Taking Anhui province as an example, this paper analyzes the change in its precipitation over the past six decades. 【Method】 Daily precipitation measured from 1960 to 2019 from 24 meteorological stations across the province was used to analyze its spatiotemporal variation using trend analysis and mutation testing. 【Result】 ①Temporally, precipitation in summer in the province accounts for about 40% of the annual precipitation; spatially, precipitation increases from the north to the south, and there are more precipitation and rainy days in the mountainous areas than in the flatted plains. The highest precipitation and rainy days are in Dabie Mountains in the south, and the lowest precipitation is in the Huaibei plain. ②The annual precipitation in 22 stations has been increasing largely due to the increase in heavy rains over the past six decades. ③Among the 24 stations, 12 have seen abrupt changes in precipitation pattern, but all these occurred in Jianghuai plain (1969 and 2012) and the mountainous areas (2008). 【Conclusion】 The precipitation in Anhui province varies spatially, and the probability of extreme precipitations that lead to flooding has tended to increase. These results provide guidance for improving water resource management and developing mitigation strategies to ameliorate flooding and drought in the province.

Under the conditions of global climate change, soils have undergone more complex and frequent cycles of wetting and drying, which has had a significant impact on soil respiration. In order to explore the response of CO2 emissions from salt-affected soils to biochar (BC) at different pyrolysis temperatures under drying-rewetting conditions, an indoor microcosmic culture experiment was conducted to add maize straw BC at different pyrolysis temperatures (300°C and 600°C) to salt-affected soils to study the influence of BC at different pyrolysis temperatures on the characteristics of CO2 emissions under drying-rewetting conditions. The results indicated that the addition of BC significantly altered the CO2 emission rate from the soil, subsequently influencing the mineralization of soil organic carbon. BC produced at varying pyrolysis temperatures exhibited distinct effects on the CO2 emission rates. Specifically, BC pyrolyzed at high temperatures inhibited the mineralization of soil organic carbon, whereas BC produced at low temperatures facilitated this mineralization process. This finding will provide a theoretical and scientific foundation for assessing the carbon sequestration potential of coastal wetlands and for the development of carbon sequestration technologies.

Restricted by economic and social development conditions and the level of domestic regulatory system construction, the traditional host country-centered regulatory approach makes it difficult to ensure "responsible investment" by overseas farmland investment companies. The jury is still out on whether international law can directly impose obligations and responsibilities on companies. Therefore, it is realistically necessary for the investor's home country to regulate any behavior that infringes on the human rights and environment of residents of the host country during the company's overseas farmland investment. We used a panel fixed effects model and the dummy variable method to construct regression indicators based on international treaties. This study finds that promulgating responsible investment treaties can significantly promote the scale and number of international farmland investments, which also further led to the problem of differentiation among overseas farmland investors. We further discussed the lack of binding force of current international rules and the difficulty in coordinating the interests of multiple parties. In the regulatory system of the home country, there are still problems, such as insufficient supply of adequate laws, and lack of administrative guidance. Measures such as deepening negotiations on international rules for responsible overseas farmland investment, further leveraging the role of land ownership in responsible overseas farmland investment, improving existing domestic legislation, and strengthening administrative guidance on overseas farmland investment can be used as countermeasures. [ABSTRACT FROM AUTHOR]

In recent years, coal gasification slag has been widely used as an adsorbent in many countries worldwide. To better understand remediation of soil heavy metal pollution by coal gasification slag, it is necessary to examine and analyze the influence mechanism of the adsorption characteristics of coal gasification slag on the migration of heavy metal ions in the soil. In this study, we used a soil water movement model and convection-dispersion equation and constructed a model of heavy metal migration after soil improvement by coal gasification slag; then, we evaluated and predicted the influence of heavy metal infiltration with liquid on groundwater after soil improvement. Combined with the soil column experiment, HYDRUS-1D software was used to predict the migration behavior of heavy metals in the soil. The results showed that the dispersion of the sample with coal gasification slag was smaller than that of the original soil sample, and the permeability coefficient of the soil was reduced by 59.34%; after adding coal gasification slag, the adsorption rates of Cd2+ and Pb2+ on the soil samples were higher than 95% and 99% respectively. The constructed heavy metal migration model was fitted well and predicted the migration behavior of heavy metals in the soil satisfactorily. The addition of coal gasification slag can effectively prevent the infiltration of Cd2+ and Pb2+ in the soil and can mitigate groundwater pollution. Therefore, using the adsorption characteristics of coal gasification slag to study the migration behavior of Cd2+ and Pb2+ in soil has important practical significance for soil adsorption and provides a new idea for the comprehensive utilization of coal gasification slag. [ABSTRACT FROM AUTHOR]