减氮配施腐植酸对海岛棉植株及土壤养分的影响

Effects of nitrogen reduction combined with humic acid application on island cotton plants and soil nutrients

  • 摘要: 为探究减氮配施腐植酸对海岛棉植株及土壤养分的影响, 于2022—2023年, 采用单因素随机区组试验, 以海岛棉“新78”为材料, 设置不施氮(CK)、正常施氮600 kg·hm−2 (OF1)、减量施氮50% (300 kg·hm−2, OF2)、减量施氮300 kg·hm−2+腐植酸150 kg·hm−2 (OF3)、施腐植酸300 kg·hm−2 (OF4) 5个处理, 分析减氮及配施腐植酸对海岛棉植株干物质积累、氮磷钾积累和分配、棉田土壤养分及产量品质的影响。结果表明: 减氮配施腐植酸能有效促进海岛棉干物质积累并优化分配, 其中OF3干物质积累量最高, 两年平均较CK、OF2、OF4分别显著提高27.58%、19.81%、12.99% 与OF1无显著差异。OF3可有效促进养分向生殖器官转运, 其分配比例随生育期推进逐渐增加, 两年平均积累量较CK显著增加25.07%, 与OF1无显著差异。减氮配施腐植酸可显著提升海岛棉植株全氮、全磷、全钾积累量, 并促进氮磷钾积累向生殖器官分配。花铃期和吐絮期, OF3植株全氮、全磷、全钾的积累量显著高于CK, 虽然全氮积累量略低于OF1, 但差异不显著。OF3能够促进海岛棉养分向生殖器官分配, 吐絮期生殖器官全氮、全磷、全钾占比最高, 分别为63.65%、62.95%、59.69%。减氮配施腐植酸可显著增加土壤有机质和碱解氮含量。花铃期和吐絮期, 土壤有机质含量以OF4最高, OF3次之; 土壤碱解氮含量以OF1最高, OF3次之; 土壤速效磷、速效钾含量OF3最高, OF4次之。此外, 减氮配施腐植酸不仅能提高海岛棉产量, 还能使海岛棉纤维品质保持较高水平。两年试验中, OF3平均籽棉产量达6 581.15 kg·hm−2, 较CK、OF1、OF2、OF4分别提高36.91%、4.36%、11.57%、18.85%; 平均断裂比强度较CK、OF2、OF4分别提高3.35%、1.31%、3.79%; 平均马克隆值较CK、OF2、OF4分别改善8.75%、2.23%、8.37%, 且OF3与OF1的各项纤维指标无显著差异。因此, 在新疆海岛棉主产区生产中采用施氮300 kg·hm−2+腐植酸150 kg·hm−2的施肥策略, 可显著提高海岛棉植株氮磷钾积累量、土壤有机质和速效氮含量、籽棉产量, 实现氮肥高效利用和产量提升的双重目标。

     

    Abstract: To investigate the effect of nitrogen reduction with humic acid application on island cotton plants and soil nutrients, in 2022−2023, a one-factor randomized block trial was conducted with Island Cotton ‘New 78’ as the material, five treatments were set up: no nitrogen application (CK), normal nitrogen application of 600 kg·hm−2 (OF1), reduced nitrogen application of 50% (300 kg·hm−2, OF2), and reduced nitrogen application of 300 kg·hm−2 + humic acid 150 kg·hm−2 (OF3), and humic acid 300 kg·hm−2 (OF4), to analyze the effects of nitrogen reduction and humic acid on dry matter accumulation, nitrogen, phosphorus and potassium accumulation and distribution, soil nutrients and yield quality of island cotton plants. The results showed that: Reducing nitrogen application combined with humic acid effectively promoted dry matter accumulation and optimized dry matter distribution in island cotton. Among them, OF3 exhibited the highest dry matter accumulation, with a two-year average significantly higher than CK, OF2, and OF4 by 27.58%, 19.81%, 12.99%, respectively, while showing no significant difference compared to OF1. OF3 could effectively promote the transport of nutrients to reproductive organs, and the distribution proportion gradually increased with the progress of the growth period. The two-year average accumulation was significantly increased by 25.07% compared with CK, and there was no significant difference from OF1. Nitrogen reduction and humic acid application could significantly increase the accumulation of total nitrogen, total phosphorus and total potassium in island cotton plants, and promote the allocation of nitrogen, phosphorus and potassium accumulation to reproductive organs. At the bolling and flocculation stages, the accumulations of total nitrogen, total phosphorus and total potassium in OF3-treated plants were significantly higher than those in CK, although the accumulations of total nitrogen were slightly lower than those in OF1, but the differences were not significant. OF3 could promote the allocation of nutrients from the Island cotton plants to the reproductive organs, and the proportion of total nitrogen, total phosphorus and total potassium to reproductive organs was the highest during the flocculation stage, with the percentages of total nitrogen, total phosphorus and total potassium being 63.65%, 62.95% and 59.69%, respectively. Nitrogen reduction with humic acid can significantly increase soil organic matter and alkaline nitrogen content. During the flowering and fluttering periods, soil organic matter content was highest in OF4 and second in OF3; soil alkaline nitrogen content was highest in OF1 and second in OF3; soil available P and available K content was highest in OF3 and second in OF4. In addition, nitrogen reduction with humic acid not only improves the yield of island cotton, but also keeps the fiber quality of island cotton at a high level. In the 2-year experiment, the average seed cotton yield of OF3 reached 6 581.15 kg·hm−2, which was 36.91%, 4.36%, 11.57%, and 18.85% higher than that of CK, OF1, OF2, and OF4, respectively. The average breaking tenacity improved by 3.35%, 1.31%, and 3.79% compared to CK, OF2, and OF4, respectively, the average micronaire value was improved by 8.75%, 2.23% and 8.37% compared with CK, OF2 and OF4, respectively, and there was no significant difference in all fiber quality parameters between OF3 and OF1. Therefore, the fertilization strategy of applying 300 kg·hm−2 of nitrogen + 150 kg·hm−2 of humic acid in the production of the main production area of island cotton in Xinjiang can significantly increase the nitrogen, phosphorus and potassium accumulation of island cotton plants, improve the content of soil organic matter and quick-acting nitrogen, and obtain a higher seed cotton yield, in order to achieve the dual goals of efficient use of nitrogen fertilizer and yield enhancement.

     

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