Controlled-release urea derived from various coating materials on the impacts of maize production: A meta-analysis

Controlled release urea (CRU) represents an efficacious solution that can increase maize yield, reduce negative environmental impacts, and improve soil quality. Nevertheless, the impact of various coating materials on maize production remains to be elucidated. A global meta-analysis based on 822 observations of 220 studies indicated that application of CRU instead of urea increased maize yield by 6.46 %, nitrogen use efficiency (NUE) by 33.23 %, soil organic carbon (SOC) by 4.07 %, and soil pH by 1.01 %, and significantly decreased nitrous oxide (N2O) emission and ammonia (NH3) volatilization by 3.61 % and 54.08 %, respectively. The effectiveness of different CRU coating materials on maize production varied depending on nitrogen application rate, soil pH, SOC content, and soil texture. Furthermore, resin-based coated urea (RCU) was the most effective in reducing NH3 volatilization (78.84 %) and increasing SOC content (11.26 %). Sulfur-based coated urea (SCU) was found to be the most effective in reducing N2O emissions (22.18 %), while sulfur+resin-based coated urea (R+SCU) appeared to have the greatest impact on increasing yield (11.29 %). Additionally, polymer-based coated urea (PCU) was the most effective method in increasing NUE (35.37 %) and soil pH (1.67 %). In conclusion, it is recommended that the most appropriate types of CRU be selected based on the amount of nitrogen applied and the soil conditions in order to enhance the effectiveness of CRU in maize production. These findings present significant implications for sustainable maize production and can inform the development of more effective CRU products. [Display omitted] •The effects of controlled release urea (CRU) on maize were quantified.•Effects of coating materials CRU on maize production were quantitatively analyzed.•Compared with conventional urea, CRU significantly increased maize yield.•The CRU type should be selected according to nitrogen rate and soil conditions.