Solar radiation utilization characteristics of double‐season rice in China

Abstract

AbstractDouble‐season rice (Oryza sativa L.) (i.e., early‐ and late‐season rice; ESR and LSR, respectively) cropping system is a major rice production system in China. Early‐season rice generally produces less biomass and consequently lower grain yield than LSR. However, limited information is available on the critical physiological factors that contribute to the difference in biomass production between ESR and LSR. To address this knowledge gap, field experiments were conducted to compare solar radiation utilization characteristics between ESR and LSR in 2 yr. Results showed that aboveground biomass and grain yield in ESR were 3–23% and 3–11% lower than those in LSR, respectively. The ESR had a 10–13% lower radiation interception percentage and a 13–28% lower radiation interception amount (RIA) but a 7–12% higher radiation use efficiency (RUE) than LSR. These results suggest that radiation interception capacity is a critical physiological factor that contributes to the differences in biomass production and grain yield between ESR and LSR. In addition, this study found a close relationship between RUE and the ratio of radiation interception amount (RIA)/nitrogen uptake amount (RIA/NUA ratio), suggesting that the RIA/NUA ratio is a useful physiological parameter in determining RUE in rice.