Improving the estimation and partitioning of plant nitrogen in the RiceGrow model

Abstract

Plant nitrogen (N) links with many physiological progresses of crop growth and yield formation. Accurate simulation is key to predict crop growth and yield correctly. The aim of the current study was to improve the estimation of N uptake and translocation processes in the whole rice plant as well as within plant organs in the RiceGrow model by using plant and organ maximum, critical and minimum N dilution curves. The maximum and critical N (Nc) demand (obtained from the maximum and critical curves) of shoot and root and Nc demand of organs (leaf, stem and panicle) are calculated by N concentration and biomass. Nitrogen distribution among organs is computed differently pre- and post-anthesis. Pre-anthesis distribution is determined by maximum N demand with no priority among organs. In post-anthesis distribution, panicle demands are met first and then the remaining N is allocated to other organs without priority. The amount of plant N uptake depends on plant N demand and N supplied by the soil. Calibration and validation of the established model were performed on field experiments conducted in China and the Philippines with varied N rates and N split applications; results showed that this improved model can simulate the processes of N uptake and translocation well.

Does the Organ-Based N Dilution Curve Improve the Predictions of N Status in Winter Wheat?

“…established more than 20 years ago and are PDM based, which limits their application in crop models [47]. Thus, although the PDM-based curve was the most reliable predictor of RY, the other three critical N concentration dilution curves we constructed also performed sufficiently well.…”

“…This study identified that a different NNI value is necessary to enrich the indicator group for simulating the growing status, to develop ideal crop models. Most of the Nc curves in existing crop models were established more than 20 years ago and are PDM based, which limits their application in crop models [47]. Thus, although the PDM-based curve was the most reliable predictor of RY, the other three critical N concentration dilution curves we constructed also performed sufficiently well.…”

Interaction of Genotype, Environment, and Management on Organ-Specific Critical Nitrogen Dilution Curve in Wheat

“…At present, many crop growth models use organ N c dilution curves to estimate organ N distribution. The N c curve for APSIM (Agricultural Production Systems sIMulator) [ 37 ], STICS (Simulateur Multidisciplinaire pour les Cultures Standards) [ 51 ], and RiceGrow [ 52 ] models has been developed using a small dataset or special planting conditions, which have yielded great uncertainty. Especially for crop growth modeling, this difference in N dilution effects at the organ level seems to be a useful and logical method for describing their different roles as storage pools and assimilation organs.…”