Dry matter production, radiation interception and radiation use efficiency of potato in response to temperature and nitrogen application regimes

- Higher temperatures severely curbed potato dry matter and radiation use efficiency.
- N supply enhanced leaf area, light interception and dry matter production.
- In high temperature seasons, less N should be supplied to potato crops.

A meta-analysis of 12 irrigated field experiments conducted from 2003 to 2014 was performed to examine the combined effects of climate variability and nitrogen (N) application on dry matter production of potatoes in a humid temperate climate. Seasonal mean temperature ranged from 15.3 to 17.7 °C while N rate varied from 0 to 180 kg ha−1. Statistical analysis using mixed modelling detected two clear features: Both temperature and N supply were important factors for dry matter production. Higher temperatures were associated with decreased dry matter production mainly through its negative effect on radiation use efficiency (RUE) when comparing inter-annual variation in dry matter production. The loss of tuber dry matter was c. 10% per °C, which is higher than estimated in previous studies. Specifically, compared to mean air temperature from end of tuber initiation to maturity, mean air temperature from emergence to end of tuber initiation was more important for dry matter production. N supply promoted dry matter production (p < 0.001) mainly by increasing accumulated intercepted radiation during the growing season (p < 0.001) rather than radiation use efficiency. Elevated temperature reduced the potential tuber dry matter production as well as the N supply that was needed to maximize tuber dry matter yield. Therefore, in a season when temperature is high, less N should be supplied to potato crops.