The Journal of Integrative Agriculture recently published a study by Haotian Chen, Yunyi Gu, Shengkai Yang, and a team of researchers from Yangzhou University that explores a promising strategy for modern rice production. As the global population continues to expand and water resources become increasingly scarce, agricultural scientists are searching for ways to produce more food with fewer resources. This research demonstrates that a synergistic approach combining specific water management techniques with soil amendments can successfully address the dual challenges of water scarcity and the rising demand for premium-quality rice. By moving away from traditional continuous flooding and incorporating wheat straw biochar, the study reveals a path toward more sustainable and productive rice farming.

The core findings of the two-year field experiment indicate that the co-application of mild alternate wetting and drying irrigation and biochar significantly outperforms traditional rice cultivation methods. In terms of productivity, the combination led to a grain yield increase of 18.7 percent in the first year and 13.4 percent in the second year. This improvement is particularly notable because the biochar was only applied once at the beginning of the study, yet its positive effects persisted into the following season. The researchers identified that the yield boost was primarily driven by an increase in the number of spikelets per panicle and a higher percentage of filled grains, rather than simply increasing the number of tillers. This suggests that the plants became more efficient at utilizing nutrients and water to produce viable grain.

Beyond simple yield increases, the study provides extensive evidence that this cultivation method comprehensively improves the quality of the rice. One of the most significant physical improvements was seen in milling quality, where the head rice rate—the proportion of whole grains remaining after milling—increased by nearly 25 percent. Furthermore, the appearance of the rice improved as chalkiness was reduced by up to 38 percent. Chalkiness is often viewed as a defect in rice because it makes the grains more brittle and less attractive to consumers. By reducing these opaque areas, the researchers produced a grain that is physically stronger and more commercially valuable.

The research also delved into the chemical and sensory properties of the rice, finding that the combination of biochar and controlled irrigation optimized the starch and protein composition. The resulting rice exhibited a higher apparent amylose content, which is a key factor in determining the cooking and eating quality. This change led to a lower gelatinization temperature and enthalpy, meaning the rice requires less time and energy to cook. Additionally, the rice flour showed higher peak viscosity, which generally correlates with a more desirable texture when eaten. From a nutritional standpoint, the study found a favorable shift in protein fractions, specifically an increase in digestible glutelin and a decrease in less nutritious prolamin.

An unexpected but highly beneficial result of the study was the impact on starch digestibility. The researchers discovered that rice grown with this synergistic method had a significantly slower starch digestion rate. In a world where metabolic diseases such as diabetes are on the rise, producing staple foods that cause a slower, more controlled release of glucose into the bloodstream is a major public health advantage. This effect is attributed to the increased amylose content and the specialized structure of the starch granules formed under these specific growth conditions. This suggests that biochar and smart irrigation can play a role in producing “healthier” staples without sacrificing the taste or texture that consumers expect.

The physiological mechanisms behind these improvements are rooted in what the authors call the rewatering and compensatory effects. The mild drying periods encourage the rice plants to develop stronger, more active root systems, while the subsequent rewatering phases trigger a surge in leaf photosynthetic rates. The presence of biochar in the soil helps stabilize moisture levels in the root zone, preventing the plants from experiencing severe stress during the drying cycles. This enhanced root and leaf activity allows the plant to accumulate more carbohydrates in its stems and then efficiently move those sugars into the developing grains during the final stages of growth. This coordinated metabolism ensures that the grains are well-filled and rich in the components that define high-quality rice.

Source: Chen, H., Gu, Y., Yang, S., Zhong, X., Jia, M., Cai, W., Zhu, K., Gu, J., Huang, K., Zhang, H., Wang, Z., Zhang, Z., Liu, L., Zhang, J., & Zhang, W. (2026). Co-applying mild alternate wetting and drying with biochar synergistically improves rice yield and quality. Journal of Integrative Agriculture.