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Chinese Agricultural Science Bulletin ›› 2023, Vol. 39 ›› Issue (4): 1-6.doi: 10.11924/j.issn.1000-6850.casb2022-0083

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Effects of Nitrogen Fertilizer Topdressing Rates on SPAD Value and Dry Matter Accumulation and Distribution of Upland Cotton in Southern Xinjiang

DU Shanshan(), LUO Jing, YAO Qingqing(), SUN Huijian, HE Zhongsheng, WANG Dongli   

  1. Xinjiang Bayingol Mongolian Autonomous Prefecture Agricultural Science Research Institute, Korla, Xinjiang 841000
  • Received:2022-02-08 Revised:2022-04-05 Online:2023-02-05 Published:2023-01-31

Abstract:

To figure out the effect of nitrogen fertilizer topdressing rate on the SPAD value and dry matter accumulation and distribution of upland cotton, we selected local main cultivar ‘Ba 43541’ as the material and set 4 nitrogen fertilizer topdressing levels (no nitrogen topdressing N0, 50% reduction of conventional nitrogen topdressing N1, conventional nitrogen topdressing N2, and 50% increase of conventional nitrogen topdressing N3). Leaf SPAD value, dry matter accumulation and distribution, yield and nitrogen utilization of cotton under the 4 treatments were measured. The results showed that 50% reduction of conventional nitrogen topdressing could increase the SPAD value and SPAD accumulation value of upland cotton in every growth period, the dry matter conversion ratio of reproductive organs reached the highest of 60.53%, the yield was 6581.32 kg/hm2 and increased by 1.4%-16.5% compared with that of other treatments. The partial factor productivity and the agronomic use efficiency of nitrogen fertilizer were also significantly higher than those of other treatments. Although 50% reduction of conventional nitrogen topdressing did not significantly increase the cotton yield, it could significantly increase the partial factor productivity and the agronomic use efficiency of nitrogen fertilizer, and should be recommended in production practice.

Key words: nitrogen fertilizer topdressing, upland cotton, SPAD, dry matter accumulation and distribution