Publications

Hu, S.; Mo, X. (2014). Prediction of crop productivity and evapotranspiration with two photosynthetic parameter regionalization methods. JOURNAL OF AGRICULTURAL SCIENCE, 152(1), 119-133.

Abstract
Parameter regionalization is the foundation for the spatial application of an ecosystem model at the canopy level and has been improved greatly by remote sensing (RS). Photosynthetic rate is restricted by the carboxylation rate, which is limited by the activity of the enzyme Rubisco. By including RS normalized difference vegetation index (NDVI) and census data of grain yield at the county level in an ecosystem model (vegetation interface processes (VIP) model), the pattern of photosynthetic parameter V (cmax) (maximum catalytic activity of Rubisco) of winter wheat was obtained and then used to simulate the wheat yield and evapotranspiration (ET) in the North China Plain (referred to as the V (cmax) method). To evaluate its performance, the simulated yield and ET were compared with those derived by the leaf area index (LAI) method using the retrieved LAI from NDVI to drive the VIP model. The results showed that the V (cmax) method performed better than the LAI method in highly productive fields, while the LAI method described the inter-annual variations of yield more favourably in fields with low productivity. Over the study area, average yield (4520kg/ha) and seasonal ET (360mm) simulated by the LAI method was slightly lower than those simulated using the V (cmax) method (4730kg/ha for yield and 372mm for ET). Compared with the census data of yield, the relative root mean square error (RMSE) of grain yield with V (cmax) method (0 center dot 17) was lower than that of the LAI method (0 center dot 20). In conclusion, the physical model with spatial V (cmax) pattern from remote sensing is reliable for regional crop productivity prediction.

DOI:
10.1017/S0021859612000901

ISSN:
0021-8596; 1469-5146