AUTHOR=Hamani Abdoul Kader Mounkaila , Abubakar Sunusi Amin , Si Zhuanyun , Kama Rakhwe , Gao Yang , Duan Aiwang 

TITLE=Suitable split nitrogen application increases grain yield and photosynthetic capacity in drip-irrigated winter wheat (Triticum aestivum L.) under different water regimes in the North China Plain

JOURNAL=Frontiers in Plant Science

VOLUME=13

YEAR=2023

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2022.1105006

DOI=10.3389/fpls.2022.1105006

ISSN=1664-462X

ABSTRACT=<p>Chemical fertilizer overuse is a major environmental threat, critically polluting soil and water resources. An optimization of nitrogen (N) fertilizer application in winter wheat (<italic>Triticum aestivum</italic> L.) in association with various irrigation scheduling is a potential approach in this regard. A 2-year field experiment was carried out to assess the growth, yield and photosynthetic capacity of drip-irrigated winter wheat subjected to various split applications of urea (240 kg ha<sup>−1</sup>, 46% N). The eight treatments were, two irrigation scheduling and six N application modes in which, one slow-release fertilizer (SRF). Irrigation scheduling was based on the difference between actual crop evapotranspiration and precipitation (ETa-P). The two irrigation scheduling were I<sub>45</sub> (Irrigation scheduling when ETa-P reaches 45 mm) and I<sub>30</sub> (Irrigation scheduling when ETa-P reaches 30 mm). The six N levels were N<sub>0-100</sub> (100% from jointing to booting), N<sub>25-75</sub> (25% during sowing and 75% from jointing to booting), N<sub>50-50</sub> (50% during sowing and 50% from jointing to booting), N<sub>75-25</sub> (75% during sowing and 25% from jointing to booting), N<sub>100-0</sub> (100% during sowing), and SRF<sub>100</sub> (240<sub> kg</sub> ha<sup>−1</sup>, 43% N during sowing). N top-dressing application significantly (<italic>P&lt;</italic>0.05) influenced wheat growth, aboveground biomass (ABM), grain yield (GY) and its components, photosynthetic and chlorophyll parameters, and plant nutrient content. According to the averages of the two winter wheat-growing seasons, the I<sub>45</sub>N<sub>50-50</sub> and I<sub>45</sub>SRF<sub>100</sub> treatments, respectively had the highest GY (9.83 and 9.5 t ha<sup>−1</sup>), ABM (19.91 and 19.79 t ha<sup>−1</sup>), net photosynthetic rate (35.92 and 34.59 µmol m<sup>−2</sup>s<sup>−1</sup>), stomatal conductance (1.387 and 1.223 mol m<sup>−2</sup>s<sup>−1</sup>), <italic>SPAD</italic> (69.33 and 64.03), and chlorophyll fluorescence <italic>F<sub>V</sub>/F<sub>M</sub></italic> (8.901 and 8.922). The present study provided convincing confirmation that N applied equally in splits at basal-top-dressing rates could be a desirable N application mode under drip irrigation system and could economically compete with the costly SRF for winter wheat fertilization. The I<sub>45</sub>N<sub>50-50</sub> treatment offers to farmers an option to sustain wheat production in the NCP.</p>