Abstract
Rice serves as the staple food for over 50% of the global population. Remotely-sensed based estimation of the gross primary production (GPP) and evapotranspiration (ET) of rice paddy fields is essential to assess global food security. In this study, we tested the application of a recently proposed remotely-sensed based water-carbon coupled model (PML-V2) in the lower reaches of the Poyang Lake plain, which is one of the nine production bases for crops in China. Evaluation using the eddy covariance measurements showed that, after parameter localization, the model reproduced the seasonal variations of GPP and ET for both the early rice and the late rice. The model performed reasonably well in the validation period because the key parameters (e.g., the quantum efficiency and the stomatal conductance coefficient) exhibited predictable seasonal variations. At the regional scale, the spatial distribution in multi-year GPP of rice (1365 ± 326 gCm−2year−1) can be explained by the vegetation cover fraction (R2 > 0.9); in comparison, the multi-year ET (1003 ± 65 mm/year) exhibits smaller spatial variations due to the high evaporation rate of the saturated soil surface of paddy fields. The water use efficiency of rice in this region varies around 1.35 gC/kgH2O with a standard deviation of 0.30. Our study shows that GPP and ET of rice can be estimated by remote sensing models without detailed crop management information, which is usually unavailable at regional scales.
Highlights
IntroductionThe fast-growing population is driving a fast-growing need in the food supply globally
Compared to the early rice, gross primary production (GPP) of the late rice increases more rapidly at the beginning of the growing stage (Figure 3); GPP peaks at the middle stages for the late rice, and the peaks were larger than those for the early rice, i.e., 16.64 gCm−2 day−1 and 14.45 gCm−2 day−1 for 2017 and 2018, respectively
Our results showed that water use efficiency (WUE) for rice at the Xiangtang station ranges from 1.41 gC/kgH2 O to 1.86 gC/kgH2 O for the early rice and late rice, which was consistent with the review of Wang et al [62]
Summary
The fast-growing population is driving a fast-growing need in the food supply globally. In 2050, the increase of new cropland is projected to be about 1 billion ha [1], and the food production needs to be 70% higher to meet the caloric requirements of the global population [2]. Among all the staple foods, rice is a important one because it feeds over 50% of the population worldwide [3]. Accurate estimation of rice yield and its water use, especially in the Asian monsoon region in which over 90% of the rice grows [4], is essential to guarantee global food security and sustainable development. Accurate estimation of rice yield and its water use, especially in the Asian monsoon region in which over 90% of the rice grows [4], is essential to guarantee global food security and sustainable development. 4.0/).
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
