Field Crop 2025, Vol.8, No.5, 238-246 http://cropscipublisher.com/index.php/fc 241 of weeds and reduces the number of times farmers use herbicides. Studies have shown that compared with traditional rice fields, rice-fish symbiotic fields have fewer weeds and the need for herbicides is reduced. This not only protects the environment, but also helps farmers save money on weeding. Using less chemical pesticides also reduces residual pollution in fields and water, making the ecosystem cleaner. 3.3 Enhanced biodiversity for pest regulation In addition to fish, other aquatic animals can be raised in rice fields, such as snails, shrimps, and small insects. These animals can increase the number of species in the field and form a more balanced ecosystem. In this ecosystem, some animals will eat pests, while others will compete with pests for living space, thereby suppressing the development of pests. Studies have also found that rice-fish symbiotic fields have richer species, the ecosystem has a stronger "self-repair" ability, and has a better control effect on pests (Ibrahim et al., 2023). Because there are so many "helpers", farmers can use less pesticides, while maintaining a good level of yield and ecology. This system that relies on nature to help is more environmentally friendly and easier to sustain in the long run. It not only protects the environment, but also allows farmers to earn more. 4 Eco-environmental Benefits Beyond Chemical Reduction 4.1 Improved water quality and aquatic health Rice-fish symbiosis not only reduces pesticides and fertilizers, but also significantly improves water quality. The water in rice fields often comes from wastewater from aquaculture, such as water from fish farming. There are a lot of nutrients such as nitrogen and phosphorus in the water. Rice in the field will absorb these excess nutrients, so that the water becomes clean. In addition, microorganisms in the field will also help to transform these nutrients. Studies have shown that this can greatly reduce the total nitrogen, total phosphorus and chemical oxygen demand in the water (Liu et al., 2023). Clearer water is also good for fish and other aquatic animals. Harmful blue algae are less likely to break out, and the entire water ecology will be more balanced and healthier. Moreover, fish swimming in the water can make the water flow better, which helps to increase the oxygen in the water. In this way, fish and other aquatic organisms can live better, and farmland can continue to produce (Ahmed et al., 2020). 4.2 Biodiversity conservation in agroecosystems The rice-fish system can also increase the number of species in the field. The addition of fish will affect many animals and plants in the rice field, such as snails, insects, and microorganisms. These animals and microorganisms live at different "trophic levels", forming a more complex ecosystem. Studies have found that rice-fish co-culture can increase the number of predators of invertebrates, but reduce weeds and pests (Wan et al., 2019). Because there are more species, the entire ecosystem is more "resistance". If one link fails, other parts can also take over. More importantly, the addition of fish can help attract and protect some natural enemies that threaten pests. There are also many small aquatic and terrestrial animals that find their "home" in this environment, which is equivalent to helping them preserve their habitat (Berg et al., 2016; Hou et al., 2024). Therefore, this system is not only good for farmers, but also for the environment. It can provide more ecosystem benefits, such as natural insect control, water purification, and preservation of biodiversity. 4.3 Climate regulation and carbon sequestration Another great benefit of the rice-fish system is that it also helps mitigate climate change. Why? Because it helps the soil store more carbon. The increase in organic matter in the soil is like "saving money" for the land, storing carbon underground. This reduces the amount of carbon dioxide and other greenhouse gases entering the air. For example, in rice fields where fish or shrimp are raised, as long as fertilizer use is properly arranged, direct and indirect greenhouse gas emissions can be reduced, and rice yields will not decrease (Cui et al., 2023). These systems can also help regulate the temperature and humidity in the fields, making the agricultural landscape more comfortable and more suitable for plant and animal growth (Arunrat and Sereenonchai, 2022). Rice-fish farming is contributing to climate regulation and sustainable agricultural development by reducing emissions and increasing carbon storage in many ways (Zhang et al., 2024).
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