The Innovation Team of Fertilizer and Fertilization Technology of the Institute of Agricultural Resources and Regional Planning (IARRP) of the Chinese Academy of Agricultural Sciences (CAAS) revealed the benefits of using controlled-release fertilizers in optimizing the distribution of inorganic nitrogen in the soil and coordinating nitrogen absorption by maize plants. This, in turn, could lead to increased or maintained maize yields and improved economic and environmental outcomes. The research findings were published in the journal "Pedosphere."

Controlled-release fertilizers can provide a steady supply of nutrients to crops over an extended period of time, which can improve nutrient efficiency and crop productivity. The main difference between controlled-release urea and ordinary urea lies in the release rate of nutrients into the soil. Controlled-release fertilizers reduce nutrient disturbance in the soil-plant system and help maintain a balanced nutrient relationship. However, research on the underlying mechanisms of their effects is limited. The core mechanisms of controlled-release technology are related to the intensity of nutrient disturbance in the soil-plant system and the nutrient balance relationship. By releasing nutrients gradually, controlled-release urea reduces nutrient losses through leaching or volatilization, optimizing nutrient availability for plants while minimizing environmental impact.

This study found that the application of controlled-release urea (PCU) led to several positive effects on maize yield, nitrogen (N) absorption, and N balance based on a 3-year field experiments. Specifically, compared to ordinary urea (U) application, PCU increased maize yield by 4.3%, N uptake rate by 16.7%, N fertilizer utilization rate by 21.2%, while reducing apparent N loss rate by 36.2%. Additionally, PCU increased net economic benefits by 8.8%. When a 20% reduction in N was applied, 0.8PCU either increased or maintained maize yield, resulting in better comprehensive benefits (Figure 1). The mechanism of action of CRU lies in optimizing the spatial and temporal distribution of soil N. It maintains N around the root zone at different stages of maize growth, particularly in the mid to late stages. Additionally, it keeps higher levels of inorganic N in the plow layer of the soil (Figure 2, Figure 3).

Figure 1: Schematic diagram illustrating the effects of controlled-release urea on the agronomic, economic, and environmental benefits of maize.

Figure 2: Spatial and temporal distribution of inorganic nitrogen in different fertilization treatments.

Figure 3: Variation of inorganic nitrogen content in the soil during different stages of maize growth under different fertilization treatments.

Sun Mingxue, a master's student at the IARRP, and Associate Researcher Li Juan are joint first authors of this article. Researcher Yang Xiangdong and Professor Sun Zhentao from the College of Land and Environment, Shenyang Agricultural University, are the corresponding authors. The research received funding from the National Key R&D Program, the National Natural Science Foundation of China, and the Chinese Academy of Agricultural Sciences Science and Technology Innovation Project.

Paper link: https://www.sciencedirect.com/science/article/pii/S1002016023000991