Traditional farming practice of rice field co-culture is a time-tested example of sustainable agriculture, which increases food productivity of arable land with few adverse environmental impacts. However, the small-scale farming practice needs to be adjusted for modern agricultural production. Screening of rice field co-culture farming models is important in deciding the suitable model for industry-wide promotion. In this study, we aim to find the optimal rice field co-culture farming models for large-scale application, based on the notion of food productivity. We used experimental data from the Jiangsu Province of China and applied food-equivalent unit and arable-land-equivalent unit methods to examine applicable protocols for large-scale promotion of rice field co-culture farming models. Results indicate that the rice-loach and rice-catfish models achieve the highest food productivity; the rice-duck model increases the rice yield, while the rice-turtle and rice-crayfish models generate extra economic profits. Simultaneously considering economic benefits, staple food security, and regional food output, we recommend the rice-duck, rice-crayfish, and rice-catfish models. Simulating provincial promotion of the above three models, we conclude that food output increases from all three recommended models, as well as the land production capacity. The rice-catfish co-culture model has the most substantial food productivity. None of the three models threatens staple food security, as they do not compete for land resources with rice cultivation.

The linkage between land tenure security and land quality improvement investment is crucial given that the land tenure security system is a widely applied policy tool for the protection of cultivation land in developing countries. Drawing on the triple land tenure security framework, this paper examines the impact of the de jure and the de facto land tenure security on farming households’ decisions about using organic fertilizer on their plots in China, based on a national survey dataset covering 2308 plots matched with 962 farming households across 8 provinces in China (Shangdong, Shangxi, Jilin, Zhejiang, Henan, Gansu, Hunan, and Sichuan) from January to July 2013. The empirical results show that the de facto land tenure security affected the use of organic fertilizer by the farming households positively. In comparison, the impact of the de jure land tenure security on the use of organic fertilizer by farming households was modest. It is suggested that the government should implement the policies effectively to promote de jure land tenure security and encourage farming households to make sustainable land investment.