AUTHOR=Chang Liying , Xiong Xin , Hameed Muhammad Khalid , Huang Danfeng , Niu Qingliang 

TITLE=Study on nitrogen demand model in pakchoi (Brassica campestris ssp. Chinensis L.) based on nitrogen contents and phenotypic characteristics

JOURNAL=Frontiers in Plant Science

VOLUME=Volume 14 - 2023

YEAR=2023

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2023.1111216

DOI=10.3389/fpls.2023.1111216

ISSN=1664-462X

ABSTRACT=In precision agriculture, the diagnosis of nitrogen (N) nutrition status based on plant phenotype, combined effects of soil types, agricultural practices, and environmental factors are essential for plant N accumulation, which helps to assess the N supply in plants at the right time and amount to ensure high N fertilizer use efficiency by reducing the N fertilizer applications and minimizing environmental pollution. For this purpose, three different experiments were performed. A critical N content (Nc) model was constructed based on cumulative light and temperature (LTF), N applications, and cultivation systems on yield and N uptake in pakchoi. According to the model, aboveground dry biomass (DW) accumulation was found equal or below to 1.5 t/ha, and the Nc value was observed at a constant of 4.78%. However, when DW accumulation exceeded 1.5 t/ha, Nc declined with the increase of DW accumulation, and the relationship between Nc and DW accumulation developed with the function: Nc %=4.78 x DW-0.33. A nitrogen demand model was established based on the multi-information fusion method, which integrated multiple factors, including Nc, phenotypical indexes, the temperature during the growth period, photosynthetically active radiation, and N applications. Furthermore, the model’s accuracy was verified, and the predicted N contents were consistent with the measured values (R2=0.948 and RMSE=1.96 mg/plant). At the same time, an N demand model based on N use efficiency was proposed. This study can provide theoretical and technical support for precise N management in pakchoi production.