In the face of the current popular crayfish food culture, as well as the strong development trend of rice-crayfish farming (RCF), how to exploit their unique advantages to develop the RCF model is a direction of agricultural development in Hainan Province that deserves attention. In this paper, we systematically analyze the feasibility of developing RCF in Hainan Province by investigating the changes in RCF development in Hubei Province in recent years, combined with the current state of rice production and RCF trial data in Hainan Province. The results show that: 1) Using abandoned land to develop RCF contributes to the total rice production of Hainan Province. The rice yield of RCF in the late-season is 16.30% higher than that of rice monoculture (RM), but the rice yield of RCF is severely affected by the proportion of culture ditch. 2) Compared to RM, the RCF model can reduce the application of N fertilizer to a certain extent. The nitrogen partial factor productivity (NPFP) in the early- and late-season of RCF are 32.34% and 74.43% higher than those of the RM, respectively. 3) In Hubei, the RCF model has promoted the expansion of rice cultivation area. Therefore, introducing the RCF model in Hainan can help increase the area of the rice cultivation and land utilization while reducing the abandonment of arable land. 4) Drawing on the RCF model in Hubei, Hainan would expect to gain remarkable economic benefits, since anti-seasonal RCF has huge market prospects.

Organic fertilizer is utilized to improve the organic carbon levels in arable soils, which is helpful for soil quality improvement and crop yield increase. However, the after-effect of organic fertilizer varies among regions with different temperature and precipitation conditions, and the extent of the impact remains unknown. This study aimed to investigate the impact of varying temperature and rainfall conditions on the accumulation of soil organic carbon after organic fertilizer application. A meta-analysis of 168 peer-reviewed studies published between 2005 and 2022 involving a total of 464 trials was conducted. The following was discovered: (1) In the major grain-producing areas of China, there was a significant positive correlation (p < 0.01) between latitude and soil organic carbon content. Meanwhile, temperature and precipitation had a significant negative correlation (p < 0.01) with soil organic carbon content. (2) The increase in temperature inhibited the increase in soil organic carbon storage. The improvement effect of organic fertilizer application in the low-temperature areas was significantly increased by 60.93% compared with the mid-temperature areas, and by 69.85% compared with the high-temperature areas. The average annual precipitation affected the after-effect of organic fertilizer as follows: 400–800 mm > 400 mm > more than 800 mm. (3) The influence of climatic conditions on the after-effect of organic fertilizer was more significant depending on the specific tillage practice. To increase organic fertilizer use efficiency and eliminate greenhouse gas emissions, liquid organic fertilizers with abundant trace nutrients and amino acids, which take advantage of releasing nutrients more swiftly and have a better fertilization effect, could be an alternative to traditional organic fertilizers.