Impact of controlled-release urea on rice yield, nitrogen use efficiency and soil fertility in a single rice cropping system

Qiang Wang,Lina Jiang,Ping Zou,Zhaoming Chen,Junwei Ma

doi:10.1038/s41598-020-67110-6

Qiang Wang, Lina Jiang + Show 3 more

Open Access

https://doi.org/10.1038/s41598-020-67110-6

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Journal: Scientific Reports	Publication Date: Jun 26, 2020
Citations: 33	License type: open-access

Affiliation: ZheJiang Academy of Agricultural Sciences

Abstract

Overuse of nitrogen (N) fertilizer has led to low N use efficiency (NUE) and high N loss in single rice cropping systems in southeast China. Application of controlled-release urea (CRU) is considered as an effective N fertilizer practice for improving crop yields and NUE. Here, field experiments were conducted during 2015–2017 to assess the effects of two CRUs (resin-coated urea (RCU) and polyurethane-coated urea (PCU)) on rice yields, NUE and soil fertility at two sites (Lincheng town (LC) and Xintang town (XT)). Four treatments were established at each site: (1) control with no N application (CK), (2) split application of conventional urea (U, 270 kg N ha−1), (3) single basal application of RCU (RCU, 216 kg N ha−1), and (4) single basal application of PCU (PCU, 216 kg N ha−1). The N application rate in the CRU treatment compared to the U treatment was reduced by 20%. However, the results showed that, compared to split application of urea, single basal application of CRU led to similar rice grain yields and aboveground biomass at both sites. No significant difference in the N uptake by rice plant was observed between the U and CRU treatments at either site. There were no significant differences in the N apparent recovery efficiency (NARE) among the U, RCU and PCU treatments, with the exception of that in XT in 2015. Compared to application of U, application of CRU increased the N agronomic efficiency (NAE) and N partial factor productivity (NPFP) by 17.4–52.6% and 23.4–29.8% at the LC site, and 15.0–84.1% and 23.2–33.4% at the XT site, respectively, during 2015–2017. Yield component analysis revealed that greater rice grain yield in response to N fertilizer was attributed mainly to the number of panicles per m2, which increased in the fertilized treatments compared to the CK treatment. The application of CRU did not affect the soil fertility after rice harvest in 2016. Overall, these results suggest that single basal application of CRU constitutes a promising alternative N management practice for reducing N application rates, time- and labor-consuming in rice production in southeast China.

Highlights

Overuse of nitrogen (N) fertilizer has led to low N use efficiency (NUE) and high N loss in single rice cropping systems in southeast China
These results reveal that a single basal application of controlled-release urea (CRU) can maintain rice grain yields even if the N application rate is reduced by 20% compared to that in the split application of urea
The results of present study showed that reductions in the current application rates of N fertilizer by 20% and the use of single basal applications of CRU (RCU and polyurethane-coated urea (PCU)) could maintain rice grain yields at levels that is similar to those resulting from split applications of urea in the middle and lower Yangtze River basin

Summary

Introduction

Overuse of nitrogen (N) fertilizer has led to low N use efficiency (NUE) and high N loss in single rice cropping systems in southeast China. The application of CRU did not affect the soil fertility after rice harvest in 2016 Overall, these results suggest that single basal application of CRU constitutes a promising alternative N management practice for reducing N application rates, time- and labor-consuming in rice production in southeast China. The results of a field experiment conducted by Li et al.[20] showed that CRU significantly increased the grain yield of late rice and the apparent N recovery by 6–18% and 3–17%, respectively, compared to urea application at the same N rate. Compared to single application of urea, split application can significantly increase rice grain yields and NUE, but other studies have reported no significant difference in rice grain yield between a one-time application of urea and a split application of urea in central China[20]. Many studies have shown that CRU can be applied once as basal fertilizer with no effect on rice grain yields[7]

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