scholarly journals Ecological studies on the conditions and emergence of propagules in Sagittaria trifolia L., a perennial paddy weed. V. Factors controlling seasonal variations in the development and emergence of tubers in paddy fields.

1989 ◽  
Vol 34 (4) ◽  
pp. 299-307
Author(s):  
Kazuyuki ITOH ◽  
Masuji MIYAHARA
Keyword(s):  
Seasonal Variations ◽  
Paddy Fields ◽  
Ecological Studies

Seasonal variations of CH4 and N2O emissions in response to water management of paddy fields located in Southeast China

Chemosphere ◽  
2012 ◽  
Vol 89 (7) ◽  
pp. 884-892 ◽  
Author(s):  
Huijing Hou ◽  
Shizhang Peng ◽  
Junzeng Xu ◽  
Shihong Yang ◽  
Zhi Mao
Keyword(s):  
Water Management ◽  
Seasonal Variations ◽  
Paddy Fields ◽  
N2o Emissions ◽  
Southeast China ◽  
Ch4 And N2o ◽  
Response To Water

scholarly journals Estimating the Gross Primary Production and Evapotranspiration of Rice Paddy Fields in the Sub-Tropical Region of China Using a Remotely-Sensed Based Water-Carbon Coupled Model

2021 ◽  
Vol 13 (17) ◽  
pp. 3470
Author(s):  
Guojing Gan ◽  
Xiaosong Zhao ◽  
Xingwang Fan ◽  
Henwang Xie ◽  
Weirong Jin ◽  
...  
Keyword(s):  
Primary Production ◽  
Seasonal Variations ◽  
Gross Primary Production ◽  
Regional Scale ◽  
Coupled Model ◽  
Rice Paddy ◽  
Remotely Sensed ◽  
Paddy Fields ◽  
Tropical Region ◽  
Rice Paddy Fields

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.

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