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| DOI：10.13522/j.cnki.ggps.2022092 |
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| The Effects of Different Irrigation and Nitrogen Fertilization on Photosynthesis, Protective Enzyme Activity of Flag Leaf and Yield of Drip-irrigated Winter Wheat |
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ZHAO Jinke, XU Xuexin, QU Wenkai, LIU Shuai, XU Yufan, MENG Fangang, JIA Jing, ZHAO Changxing
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Qingdao Agricultural University, College of Agriculture/Shandong Provincial Key Laboratory of Dryland Farming Agricultural Technology, Qingdao 266109, China
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| Abstract: |
| 【Objective】 Crop growth and its ultimate yield depend not only on irrigation and fertilization amounts but also on the timing of their application. Taking winter wheat as an example, this paper investigates how irrigating and nitrogen-fertilizing time affects photosynthesis, protective enzyme activity of flag leaf and grain yield.【Method】The field experiment was conducted in the 2019—2020 season with Jimai 22 used as the model plant. We compared two nitrogen fertilizations: 180 kg/hm2 (N1) and 210 kg/hm2 (N2), with each applied at jointing and anthesis stages (S2), or at jointing, anthesis and filling stages (S3). Crops in both N treatments were drip-irrigated with the irrigation amount determined by crop demand for water. The control (CK) was traditional border irrigation coupled with 240 kg/hm2 of N fertilization, with 90 kg/hm2 of the N used as basal fertilizer and the remaining top-dressed at jointing and anthesis stages, respectively. In each treatment, we measured the photosynthesis, senescence of flag leaf, yield formation and water-nitrogen use efficiency.【Result】Increasing irrigation frequency led to an increase in LAI, SPAD of the flag leaf, net photosynthetic rate, stomatal conductance, transpiration rate, as well as the content of SOD, POD, CAT, and grain filling rate. In contrast, the content of MDA decreased as the irrigation frequency increased. When nitrogen application was increased from 180 kg/hm2 to 210 kg/hm2, there was no significant change in the physiological indices. Maintaining water content in the top 0~20 cm of soil at 100% of the relative water content delayed the commencement of the decrease in photosynthesis and senescence of flag leaf, while increasing the grain weight and grain filling rate significantly during the middle-late anthesis. Compared with CK, N1+S3 increased grain quality by 5.3%, yield by 6.2%, nitrogen fertilizer partial productivity (PFPn) and irrigation water use efficiency (IUE) by 42.1% and 44.8%, respectively. Considering crop growth traits, yield, IUE and PFPn, N1+S3 is optimal for water and fertilizer use efficiency, and can be used as an improved water-nitrogen practice for drip-irrigating winter wheat in the Eastern North China Plain. |
| Key words: drip irrigation integration of water and fertilizer; winter wheat; photosynthetic characteristics; senescence characteristics; yield |
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