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Changes in rice yield and yield stability in China during the past six decades.

BACKGROUND
Increasing rice yield and its stability are important to achieving the sustainability of rice production. Rice yields have increased substantially in China during recent decades, but information on the trend in yield stability has been limited. In this study, the trends in rice yield and rice yield stability from 1949 to 2015 were analysed in China's rice production.


RESULTS
The results showed that rice yields for all 16 provinces presented the increasing trend during study period. The national annual rice yield gain was 86.0 kg ha-1 during the last six decades, varying from 48.4 to 106.0 kg ha-1 in different provinces and exhibiting linear, bi-linear, or tri-linear relationships. Remarkably, the annual yield increase was smaller in provinces dominated by double rice cropping systems than in the other provinces. Notably, rice yield stagnations have occurred in recent years at provincial and national levels. Absolute residuals over time showed slight increases in 4 of 16 provinces, indicating a reduction in yield stability in these 4 provinces. However, the relative yield residuals exhibited a clear trend towards increased yield stability for all 16 provinces. The rice yields of newer cultivars planted with improved crop management practices were consistently higher and more stable in comparison with cultivars from the beginning of the study period.


CONCLUSION
This study revealed that rice yield in China has increased substantially, accompanied by improved stability over the last six decades. Given the spatial difference, this study emphasized the priority of orienting long-term on-farm studies to investigate yield stability. This article is protected by copyright. All rights reserved.