How can science and technology solve the problem of increasing grain yield per unit area?

The North China Plain is an important “granary” in China, with its winter wheat and summer maize planting areas accounting for 73.6% and 30.6% of the national total for wheat and maize respectively. However, its agricultural production has long been trapped in the dilemma of “high input, low efficiency”—fertilizer usage has increased more than 4 times compared with 40 years ago, while grain output has only risen by 1.2 times. Problems such as over-exploitation of water resources and soil degradation have also become increasingly prominent. How to balance agricultural production and ecological protection while ensuring food security?

Recently, a team led by Professor Weifeng Zhang and Peng Ning from the College of Resources and Environmental Sciences at China Agricultural University proposed a sustainable production pathway to achieve an annual yield of 22.5 t·ha^–1 in the winter wheat-summer maize rotation system on the North China Plain, providing a scientific reference for solving this problem. The related paper has been published in Frontiers of Agricultural Science and Engineering (DOI: 10.15302/J-FASE-2025618).

The study points out that the current average annual yield of winter wheat and summer maize for farmers on the North China Plain is 12.8 t·ha^–1, while the highest yield record in the region has reached 28.1 t·ha^–1, indicating huge potential for grain yield increase. However, in traditional planting patterns, excessive fertilizer application leads to low nutrient use efficiency, continuous depletion of regional groundwater, soil organic matter content being only one-third of that in U.S. farmland, and frequent extreme climate events (such as late frost and drought) threatening crop growth. If the existing model remains unchanged, the growth in food demand by 2050 will further exacerbate resource and environmental pressures.

Through the coordinated regulation of multiple factors including “soil-crop-climate-management”, it is possible to reduce resource input while increasing yield. For example, in terms of optimizing the cropping system, appropriately delaying the sowing date of winter wheat and extending the filling period of summer maize can increase the utilization efficiency of light and heat resources at a rate of 71.7 kg·ha^–1·yr^–1; adopting the “four dense and one sparse” wide-narrow row planting technology combined with shallow-buried drip irrigation can realize precise synchronous management of water and fertilizer, reducing nitrogen input compared with traditional models while increasing wheat and maize yields.

Soil improvement is another key approach. Long-term application of organic fertilizer and straw returning can increase soil organic matter content. When soil organic matter reaches 20–30 g·kg^–1, crop yield can increase by about one-fifth, and the soil's ability to retain water and fertilizer can be enhanced. Deep plowing can break the plow layer, improve soil permeability, and when combined with no-tillage technology, it can reduce carbon emissions and achieve “carbon sequestration in soil”.

At present, the aging of agricultural labor force on the North China Plain is intensifying, and traditional experience-based planting is difficult to meet the needs of modernization. Through the “Science and Technology Courtyard” model, researchers reside in villages to conduct experiments together with farmers, transforming complex technologies into “easy to learn and use” localized solutions. For example, in the practice in Quzhou County, Hebei Province, after farmers participated in technology design, wheat and maize yields increased by 7.2% and 11.4%, respectively, and nitrogen use efficiency improved by 27%–28.1%, proving that the “scientist + farmer” collaborative innovation is an effective path for technology promotion.

The study suggests that in the future, efforts should be made to promote sustainable crop production from the following aspects: first, prioritize the strengthening of agricultural infrastructure construction and the improvement of cultivated land soil quality; second, accelerate the breeding of superior crop varieties to fully release high-yield potential; third, promote the interconnection and integration of research methods, focusing on the integrated application of superior varieties, effective methods and advanced technologies; fourth, coordinate national policies and social actions, and strengthen the construction of agricultural technology extension service capabilities.