Application of controlled release urea improved grain yield and nitrogen use efficiency: A meta-analysis.

Shuhao Zhu,Yanying Yang,Yan Xu,Rongguang Shi,Liyuan Liu,Pirjo Mäkelä

doi:10.1371/journal.pone.0241481

Abstract

The application of controlled release urea (CRU) has been proposed as a crucial method to reduce the adverse environmental effects induced by conventional urea (CU). Yet, a systematic and quantitative analysis on how CRU affects staple crop production including wheat (Triticum aestivum L.), maize (Zea mays L.), and rice (Oryza sativa L.) is lacking. Here, a meta-analysis was conducted to determine how CRU influences soil chemical properties, total nitrogen (TN) uptake, grain yield, and nitrogen use efficiency (NUE) of staple crop in China. The results indicated that CRU application significantly increased soil organic carbon (SOC), TN, and available nitrogen (AN) by 5.93%, 3.89% and 13.98% respectively overall, while soil pH showed no significant changes. Compared to the application of CU, applying CRU significantly increased grain yield by 7.23%, which was mainly owing to the higher TN uptake (9.13%) across all the studies. In addition, the application of CRU significantly increased NUE, nitrogen agronomy efficiency (NAE), utilization rate of nitrogen fertilizer (NUR), and nitrogen physiological efficiency (NPE) by an average of 23.4%, 34.65%, 25.83% and 15.8% respectively which could be attributed to the slow nitrogen (N) release characteristics of CRU. The positive effect of CRU on grain yield and NUE of staple crop was greatest when the content of SOC and TN were extremely low, indicating that it was most effective to improve grain production of infertile soil by applying CRU. The finding of this study indicated that the application of CRU should be promoted for grain production, especially for infertile soil.

Highlights

Feeding the ever-growing population without further damaging the environment is the grand challenge in the 21th century [1]
To prevent data distortion during the literature collection, the publications chosen for data analysis had to meet the following criteria: (i) the studies had to be conducted in the field instead of in a pot or greenhouse; (ii) the experiment sites had to be located in China; (iii) the studies had to be conducted with side-by-side comparisons of control and treatment groups; (iv) the means, standard deviations (SD), and sample sizes of the observations had to be reported or had the possibility of being calculated
soil organic carbon (SOC) was significantly increased by 5.93% to controlled release urea (CRU) application

Summary

Introduction

Feeding the ever-growing population without further damaging the environment is the grand challenge in the 21th century [1]. As the world’s biggest nitrogen (N) fertilizer producer and consumer, China plays an indispensable role in world food production [2]. Application of controlled release urea improved grain yield and nitrogen use efficiency: A meta-analysis fertilizer N was lost as greenhouse gas and other reactive N species, which has triggered serious environmental damage including widespread soil acidification [4], serious greenhouse effect [5] and devastating water pollution [6]. With the increasing public attention to environmental issues, Ministry of Agriculture and Rural Affairs of China formulated a policy of zero growth in chemical N fertilizer application by 2020 [7].

Methods

Results

Discussion

Conclusion