In the quest to sustain the ever-growing global population, rice remains one of the most vital staple crops, constituting a primary food source for nearly half of humanity. Ensuring stable increases in rice production while reducing environmental impacts poses one of the most urgent agricultural challenges today. China, as the largest producer and consumer of rice worldwide, has made remarkable strides in increasing per hectare yields from 2.1 tons in 1950 to an impressive 6.8 tons in 2020. This achievement, however, came at a substantial ecological cost, including excessive water usage and inefficient nitrogen fertilizer application, which culminate in soil degradation and heightened greenhouse gas emissions.
Traditional methods that fueled China’s rice production gains have largely relied on a “high input, high output” approach, consuming disproportionate amounts of water and nutrients. Studies reveal that the country’s water resource utilization efficiency in rice cultivation falls between 40% and 50% lower than the global average. Meanwhile, nitrogen fertilizer utilization languishes at only 34%, considerably below the worldwide standard. These inefficiencies not only threaten the long-term sustainability of rice farming but also contribute to environmental stress through methane emissions and soil nutrient depletion.
Recognizing these challenges, a pioneering study led by Professor Jianchang Yang of Yangzhou University critically reevaluates yield optimization in rice production. The research highlights the “harvest index” — the ratio of grain yield to the total aboveground biomass — as a pivotal metric that can be fine-tuned to reconcile the goals of yield enhancement and resource conservation. Modern rice cultivars typically exhibit a harvest index near 0.5, but there remains significant potential to surpass this benchmark by manipulating specific physiological traits.
The study identifies three critical physiological parameters that can synergistically drive improvements in both rice yield and resource utilization efficiency. Firstly, increasing the “grain-to-leaf ratio” enhances the number of grains produced per unit leaf area, balancing photosynthetic output with reproductive demand. Secondly, boosting the “sugar-to-spikelet ratio,” which quantifies the stem’s non-structural carbohydrate reserves relative to grain count prior to flowering, promises to provide vital energy reserves for efficient grain filling. Lastly, optimizing the “proportion of productive tillers” minimizes the allocation of water and nutrients to ineffective shoots, thereby streamlining canopy architecture and maximizing light interception.
Grounded in these physiological insights, scientists have developed innovative green technologies aimed at revolutionizing rice cultivation practices. The first of these is the moderate alternating wet and dry irrigation (AWMD) system, a precision irrigation technique that monitors groundwater levels and applies water based on crop growth stages and soil types. For example, in sandy soils, irrigation triggers between 8 to 10 centimeters water level drops during tillering, whereas clay soils allow deeper declines of 25 to 30 centimeters at booting without compromising plant health. By alternating wet and dry cycles, this approach curbs the proliferation of methanogenic bacteria, drastically reducing methane emissions by approximately 48% to 58%, while simultaneously conserving up to 35% of irrigation water compared to conventional continuous flooding.
Complementing irrigation innovations, the “three-standard nitrogen fertilizer application technology” dynamically calibrates nitrogen inputs by evaluating soil fertility, leaf chlorophyll content, and rice variety specifics. This approach employs SPAD readings — a measure of chlorophyll density — taken from the third and first leaves as physiological indicators to optimize top-dressing timing and quantity across critical growth stages like tillering and booting. Fertilizer formulations are precisely tailored: varieties with larger panicles receive more “flower-preserving fertilizer” to support reproductive stability, while small-panicle types are allocated higher proportions of “flower-promoting fertilizer” to enhance grain number. This targeted fertilization regime has elevated nitrogen use efficiency from a modest 34% to a more sustainable 51%, nearly aligning with global averages.
The third major advancement is “water–nitrogen coupling regulation technology,” a mathematical model-driven approach that captures the interactions between soil moisture status and nitrogen availability. By quantifying these synergies under varying environmental conditions, the technology prescribes the optimal nitrogen content required at specific soil water potentials. For instance, during the tillering stage, when the soil water potential registers at –10 kPa, maintaining plant nitrogen content around 2.94% optimizes resource use efficiency. Trials in Jiangsu and Heilongjiang provinces employing this model observed a yield boost of 9.3% alongside an impressive 27% enhancement in water use efficiency, underscoring the power of precise agro-ecological management.
Together, these technologies have been scaled and adopted across China’s seven primary rice-producing regions, including Anhui, Hubei, and Sichuan. Their implementation spans more than 10 million hectares, generating substantial economic gains estimated at $2.2 billion between 2021 and 2022 alone. Beyond the immediate financial benefits, these innovations mark a decisive step toward more sustainable and resilient rice production systems that embrace environmental stewardship without compromising productivity.
Looking ahead, researchers emphasize the crucial need to integrate cutting-edge smart agricultural technologies to simplify the complexity of field management. Automation, sensor networks, and data analytics could streamline irrigation and fertilization practices while continuously monitoring crop physiological status for real-time decision-making. Such integration promises to further reduce greenhouse gas emissions, conserve water resources, and mitigate soil degradation, harmonizing food security objectives with global climate action goals.
Moreover, the mainstreaming of these green technologies marks a paradigm shift in rice farming from input-heavy traditional practices to knowledge-intensive precision agriculture. Understanding the intricate physiological dynamics underlying crop growth enables agronomists and farmers to exploit rice’s latent yield potential without recourse to environmentally detrimental practices. The study led by Professor Yang and his colleagues thus sets an inspiring precedent for applying physiological and ecological insights directly into the field.
In conclusion, the fusion of physiological optimization with innovative agronomic technologies offers a compelling blueprint for transforming rice production systems worldwide. By tuning harvest index components, refining irrigation cycles, and tailoring nutrient regimes, it is possible not only to meet rising food demands but to do so sustainably. Continued research and broad-scale adoption of such practices will be essential to ensure that rice cultivation does not remain a contributor to environmental harm but becomes a model for green agriculture in the face of 21st-century challenges.
Subject of Research: Not applicable
Article Title: Innovation and implement of green technology in rice production to increase yield and resource use efficiency
News Publication Date: 16-Jul-2025
Web References: http://dx.doi.org/10.15302/J-FASE-2025610
References: DOI: 10.15302/J-FASE-2025610
Image Credits: Junfei GU, Xianlong PENG, Shiwei GUO, Jianwei LU, Xiaojun SHI, Yixiang SUN, Jianchang YANG
Keywords: Agriculture
