Rice Genomics and Genetics 2025, Vol.16, No.5, 260-266 http://cropscipublisher.com/index.php/rgg 263 grains. The environmental improvement and nutrient increase brought by fish also make the metabolic function of rice stronger, and it has a stronger ability to adapt to drought, high temperature and other conditions, and better overall health (Wan et al., 2019; Li et al., 2025). These changes will eventually be reflected in the rice, which will be more nutritious and taste better. 5 Water and Fertilizer Dynamics in Integrated Systems 5.1 Impact of redox conditions on rice quality In the rice-fish system, the redox state of water and soil affects the quality of rice. The presence of aquatic animals such as fish will change the redox potential in the rice field. This change will affect the nutrient activity in the soil and the efficiency of rice nutrient absorption (Nayak et al., 2018; Kaewpuangdee et al., 2024). The activity of fish makes the redox process more active, and also makes the soil more aerated and the nutrient cycle smoother. These changes help the rice root system develop better, and also improve the whole polished rice rate and transparency, making the rice quality better (Li et al., 2021). 5.2 Nutrient input from aquatic animal waste When fish swim in rice fields, they excrete a lot of feces. These feces are natural fertilizers, containing nitrogen, phosphorus, and potassium, which are very important nutrients for rice growth (Lv et al., 2020; Liu et al., 2023). With this method, you don't need to apply too much chemical fertilizer. In this way, the soil becomes more fertile and the rice grows better. If there are enough nutrients in the soil, the protein in the rice will also increase, and the nutrition will naturally be higher. 5.3 Enhanced nutrient use efficiency through system buffering The rice-fish system itself has the ability to regulate, which can help stabilize the supply of nutrients and reduce loss. Fish swimming back and forth in the system will promote nutrient circulation and reduce the situation where fertilizers are washed away or leaked by rainwater (Xie et al., 2011). This mechanism allows rice to have sufficient nutrient support throughout the growth period, which helps rice grow stronger and produce higher yields. This buffering capacity of the system can also reduce the impact of some adverse external conditions on rice, and improve the stress resistance and sustainable development of rice fields. 6 Case Studies and Empirical Evidence 6.1 Guangxi's "high-quality rice + high-quality fish" ecological and efficient breeding technology The "rice-fish symbiosis" model cleverly combines rice planting with fish farming, which not only improves the ecological benefits of farmland, but also brings tangible economic benefits to farmers. The Hehua carp mixed in the rice field can effectively reduce rice pests and diseases by foraging for pests and residues in the rice field without additional feed, thereby reducing the use of pesticides, fertilizers and herbicides (Figure 2) (Li et al., 2022). This all-weather "symbiosis and co-growth" model not only improves the ecological environment of the rice field, but also helps to improve the quality of rice and fish, and achieve green and sustainable development of agriculture. Guangxi rice field fish farming has a long history. Traditional rice field fish farming is mainly based on Hehua carp, with mature breeding models and breeding technologies, including Hehua fish brand building and publicity and other industrial links. According to statistics, the current rice field fish farming area in Guangxi is about 53 000 hectares, mainly distributed in Guilin and Liuzhou, accounting for more than 90% of the total rice field fish farming area in the region. Among them, Quanzhou County, Sanjiang Dong Autonomous County, and Rongshui Miao Autonomous County have the largest area, followed by Guanyang County and Xing'an County. In the past 10 years, with the support of relevant departments, the infrastructure of traditional rice field fish farming, such as pits (ditches), shade sheds, escape prevention fences, and shed melon planting, has been greatly improved, and the breeding output has increased from the original 15 kg/mu to 30 kg/mu. Among them, the ditch-pit rice field breeding model performed best, with a high yield of 50 kg/mu, making a huge contribution to the rice field fish farming industry in Guangxi. Under the "high-quality rice + high-quality fish" ecological high-yield breeding
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