Understanding the influence of COVID-19 on China's agricultural economy and the Chinese government's emergency measures to ease the economic impacts of viral spread can offer urgently-needed lessons while this virus continues to spread across the globe. Thus, this study collected over 750,000 words upon the topic of COVID-19 and agriculture from the largest two media channels in China: WeChat and Sina Weibo, and employed web crawler technology and text mining method to explore the influence of COVID-19 on agricultural economy and mitigation measures in China. The results show that: (1) the impact of COVID-19 on China's agricultural economy at the very first phase is mainly reflected in eight aspects as crop production, agricultural products supply, livestock production, farmers' income and employment, economic crop development, agricultural products sales model, leisure agriculture development, and agricultural products trade. (2) The government's immediate countermeasures include resuming agricultural production and farmers' work, providing financial support, stabilizing agricultural production and products supply, promoting agricultural products sale, providing subsidies, providing agricultural technology guidance and field management, and providing assistance to poor farmers to reduce poverty. (3) The order of government's immediate countermeasures is not all in line with the order of impact aspects, which indicates that more-tailored policies should be implemented to mitigate the strikes of COVID-19 on China's agricultural economy in the future.

Agricultural nutrients play a critical role in food production and human nutrition in China. Against this backdrop, agricultural extension services are essential for providing farmers with knowledge and information about nutrient management. By using a propensity score-matching (PSM) approach, this study examines the impact of agricultural extension on farmer nutrient management behavior. Survey data about rice farmers in seven provinces of rural China are used. The empirical results indicate that participation in agricultural extension has a positive impact on rationalizing farmer nutrient management behavior. However, this impact is trivial. Compared with non-participating farmers, the reduced ratio of total fertilizer use and total inorganic fertilizer use by participating farmers is only 1.7% to 3.7%, and the improved ratio of the total organic fertilizer use and the level of soil-testing-based fertilizer use by participating farmers is only 1.008% to 1.173%. Additionally, the causal impacts of agricultural extension participation on nutrient management behavior tend to be higher for more educated, risk-loving and larger-scale farmers. This study reveals that China faces great challenges in implementing improved nutrient management practices for hundreds of millions of farmers through extension services. The findings also have important implications for China’s extension system to meet the objectives of improving nutrient management.