Economic agglomeration plays an important role in China's social transformation process of industry feeding agriculture and urban supporting rural areas, and is one of the core weapons to promote agricultural economic growth and green and efficient development. Based on panel data of 41 cities in the Yangtze River Delta (YRD) from 2010 to 2020, this paper constructs an “environment-resource-energy-economy” agricultural input-output system, taking into account carbon emissions and surface pollution, and provides a more comprehensive accounting of agricultural green total factor productivity (AGTFP), the non-linear effects of economic agglomeration on AGTFP and shock responses were empirically analyzed using a panel threshold model and a panel vector autoregression (VAR), respectively. The findings show that: (1) during the period 2010–2020, the AGTFP in the YRD showed an overall rising trend with regional spatial agglomeration characteristics. (2) Economic agglomeration has a triple threshold effect on AGTFP, which was a weak facilitative effect in the early stage, inhibited by the siphoning effect of resource loss and arable land fragmentation in the growth stage, promoted by the radiation effect of external increasing return to scale in the form of sharing, matching and learning in the maturity stage, and finally tends to decline. (3) The shock response of economic agglomeration to AGTFP showed a continuous positive shock, peaking in the first period and then gradually converging to zero. (4) The heterogeneity analysis demonstrated that economic agglomeration has a considerable impact on boosting AGTFP in non-metropolitan areas and cities on the outskirts of YRD. In the future, China should effectively play a positive role in economic agglomeration on AGTFP and enhance the mutual coordination of economic agglomeration and agricultural green development in the process of urban cluster economic growth.

To explore the impact of land-use change on carbon storage, this study coupled the InVEST model and the FLUS model to analyse the spatial and temporal characteristics of carbon storage in the Qiantang River source region from 2000 to 2030. The carbon storage in the study area is evaluated which declined rapidly from 166.22 × 106 t in 2000 to 164.41 × 106 t in 2020, and the spatial distribution of carbon storage could be characterized by “the northwest and the southwest of region with higher, the east and the centre of the region with lower”. The carbon storage was simulated based on the historical trend development scenario, the food security scenario, and the ecological protection scenario. The carbon storage with the food security scenario could achieve 162.74 × 106 t in 2030. The carbon storage with the ecological protection scenario had an increase of 62.60 t/km2 compared to the historical natural tendency development. Interestingly, the food security scenario had the smallest carbon loss value which is about $1.39 × 109, and its net carbon storage value was the largest which is about $3.71 × 109. The results of this study could provide a scientific reference for the conservation of carbon storage and land use management for climate change and sustainable development. This paper also can lay the foundation for subsequent further studies such as artificial intelligence.

In the last decade, more and more attention has been paid to the efficiency of ecological products’ value in the literature. Studying the value-conversion efficiency of forest ecological products can measure and reflect the huge value contained in forests, which is of great significance to promote the transformation between “clear water and green mountains” and “gold and silver mountains” as well as solve the problem of economic development and environmental protection. Studying the value-conversion efficiency of forest ecological products can scientifically evaluate the results of the mutual transformation of “clear water and green mountains” and “gold and silver mountains”, which is of great significance for deepening the theory of the “two mountains”. This paper took Zhejiang Province as the research object, constructed an index system of forest ecological products’ value accounting, used the super-SBM model and Malmquist index to calculate the conversion efficiency of forest ecological products’ value, and proposed optimization paths according to the research results. The results showed that: (1) From 2000 to 2020, the value of forest ecological products in Zhejiang Province showed a fluctuating upward trend. In 2020, the total value of forest ecological products was RMB 973.717 billion. Among them, the value of material products was RMB 12.560 billion, the value of ecological regulatory products was RMB 726.323 billion, and the value of cultural service products was RMB 234.834 billion. (2) There were great differences in the value-conversion efficiency of forest ecological products among cities in Zhejiang Province, but the overall trend was steady and developing in a positive direction. (3) The total-factor productivity of forest ecological products in Zhejiang Province showed a fluctuating trend, and its growth was mainly limited by the technical efficiency and technological progress index. (4) The main reasons for the conversion-efficiency loss of forest ecological products’ value in Zhejiang Province were excessive input and insufficient output. The specific reasons for the loss of efficiency in different cities were different, so it is necessary to find improvement paths according to local conditions. Our research provides a new perspective for the academic community to evaluate the value-realization effect of ecological products as well as a decision-making reference for policy makers of ecological environmental protection and construction.

Green agricultural science and technology progress (GASTP) plays an important role in the green transformation of agriculture. This study calculates the contribution rate of GASTP by using the Super-SBM model in the Yangtze River Delta (YRD) from 2011 to 2020. The exploratory spatial data analysis (ESDA) method and the Fixed Effect (FE) panel data model method were adopted to empirically analyze the spatio-temporal patterns of GASTP and its driving mechanism in the YRD. The results showed that: (i) except for Shanghai from 2011 to 2015, the contribution rate of GASTP in the YRD was generally lower than 1 in Anhui Province, Jiangsu Province, and Zhejiang Province, (ii) the level of GASTP had a positive spatial correlation with the study period, except for 2017, and (iii) per capita GDP, agricultural mechanization level, agricultural financial support, and planting structure are four influencing factors of GASTP in the YRD, while total retail sales of social consumer goods and total exports did not have significant effects on GASTP in the YRD. Therefore, we need to increase the opportunities to exchange GASTP experience between cities, improve the environment for agricultural technology extension, and develop follow-up monitoring mechanisms.

Rural solid waste management is a severe challenge in China. The Public-Private Partnership (PPP) is an effective method for rural solid waste management. However, policy efforts aimed at stimulating the adoption of PPP in rural solid waste management have been limited in their success. This study aims to empirically investigate the determinants of rural solid waste management PPP adoption in China. First, this study builds a theoretical model that consists of factors related to the institutional environment and market and proposes theoretical hypotheses. Then, using the balanced provincial panel data of 150 samples from 2015 to 2019, this study applies various count regression models and truncated regression models to empirically test the theoretical hypotheses. The results show that provinces with higher fiscal transparency, financial burdens, and market demand tend to adopt more PPP, while provinces with lower per capita GDP and market openness index ratings have a stronger motivation to initiate more PPP. In contrast, investment institutional environment factors have no impact on PPP adoption. To stimulate the development of PPP in rural solid waste management, this study proposed that a good-governed government and a strong market demand are critical foundations, and also a debt-risk prevention and evaluation system should be established to avoid local debt risks resulting from over-adoption of PPP.