Global synthesis of nitrogen management in sugarcane systems: Decoding climate-soil-management drivers of Brazil-China contrasts

Abstract

Context

Global sugarcane systems exhibit critical N management disparities; Brazil applies only one-third to one-seventh of the N fertilizer amount used in China, but achieves 30–50 % higher yields. Decoding these mechanisms is critical for closing yield gaps and optimizing global N-efficient production.

Objective

This study aimed to determine the response of sugarcane cropping systems to N fertilizers across different countries and to provide optimized N management strategies for sugarcane production.

Methods

We synthesized 967 observations from 81 articles published between 2000 and 2023. By differentiating data between Brazil and China, this study employed subgroup, random forest, and regression analyses to quantify how climatic conditions, soil properties, and agronomic practices influence the N fertilization responsiveness of sugarcane.

Results

Synthetic N fertilization increased cane yield (+20.0 %) and N uptake (+59.6 %) in Brazil compared to + 35.2 % and + 82.5 % in China, respectively, with Chinese soils exhibiting greater NO₃^- and NH₄⁺ contents. Brazilian systems showed broader variability in mean annual temperature (MAT), mean annual precipitation (MAP), soil organic matter (SOM), and soil total N (STN) than Chinese systems. MAT and STN levels emerged as the primary drivers of cane yield and N uptake responses in Brazil, respectively, in contrast to STN levels and N application rate dominance in China. Optimal thresholds were MAT > 20 ℃ and MAP > 1300 mm (Brazil) versus SOM < 30 g·kg⁻¹ and STN < 0.5 g·kg⁻¹ (China). N use efficiency (NUE) correlated positively with STN in Brazil (N rate-independent) but inversely in China. The threshold for partial factor productivity of N (PFPN) in Brazil and China occurred at N fertilizer application rates of 71.6 and 159.1 kg N·ha⁻¹, respectively, while the response threshold for cane yield appeared at 140 and 276 kg N·ha⁻¹.

Conclusion

Chinese sugarcane showed a stronger N response than Brazilian sugarcane. Brazilian soils with high SOM maintain inherent N mineralization compared to China's SOM-deficient systems with constrained native N availability. Brazilian N management requires climate-adapted approaches, whereas China requires soil health restoration through organic C and N enrichment to boost N efficiency.

Significance

This meta-analysis systematically compared the N supply patterns in Brazilian and Chinese sugarcane cropping systems, revealing that soil N provisioning is a critical determinant for sustaining high and stable yields, while providing actionable insights for optimizing global sugarcane N management strategies.