The Effects of Different Water and Nitrogen Methods on Fluorescence Characteristic and growth of rice in Black Soil Region on Songnen Plain, Northeast China

In order to study the combined effects of different water and nitrogen methods on the fluorescence characteristic and growth of rice, to investigate a suitable method with higher efficiency utilization of water and nitrogen for rice growth in black soil region on Songnen plain, northeast China. An experiment with two water treatments (control irrigation vs. flood irrigation) and six nitrogen fertilizer levels (0, 60, 85, 110, 135, 160 kg/ha) was carried out in field conditions. The results showed that the actual photochemical quantum efficiency (ΦPSII), the electron transfer rate (ETR) and the excitation energy capture efficiency (Fv′/Fm′)\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ ({{F_{v}^{{\prime }} } \mathord{\left/ {\vphantom {{F_{v}^{{\prime }} } {F_{m}^{{\prime }} }}} \right. \kern-0pt} {F_{m}^{{\prime }} }}) $$\end{document} had no found significant difference (P > 0.05) across the two water treatments. Among nitrogen treatments, the ΦPSII, ETR and Fv′/Fm′\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ {{F_{v}^{{\prime }} } \mathord{\left/ {\vphantom {{F_{v}^{{\prime }} } {F_{m}^{{\prime }} }}} \right. \kern-0pt} {F_{m}^{{\prime }} }} $$\end{document} with flood irrigation reached the maximum values with 110 kg/ha treatment. Between the two water treatments, the control irrigation had the highest values in root length, root mass, root surface area and root volume, and all of them approached the climax values with 110 kg/ha treatment. Across all treatment, the highest harvest index was 110 kg/ha nitrogen rate. The water consumption (ET) was increased with the increase of nitrogen fertilizer application. However, both water use efficiency and nitrogen use efficiency achieved the highest values with 110 kg/ha treatment. Therefore, the results of this experiment provide a scientific reference for efficient utilization of water and nitrogen in black soil region on Songnen plain in northeast of China.