• ISSN 1008-505X
  • CN 11-3996/S

高磷条件下追氮时期对水蓼磷积累能力和土壤磷去除潜力的影响

Effects of nitrogen fertilizer topdressing time on the phosphorus-accumulation capacity and soil phosphorus-removal potential of Polygonum hydropiper under phosphorus-enriched soils

    摘要
  • 摘要:
    目的 施氮能够提高植物对磷的提取能力。本研究探讨了不同追氮时期对磷富集植物水蓼磷积累能力及土壤磷去除效果的影响，为施氮措施促进植物提取土壤中过剩磷提供科学依据。
    方法 采用土培盆栽试验，以磷富集植物矿山生态型水蓼(ME)和非矿山生态型水蓼(NME)为研究材料，在施氮(N)量为 100 mg/kg土且氮肥基追比为1∶1条件下，设5个追氮时期，分别为移栽后第5、6、7、8和9周，以不追施氮肥处理为对照(CK)，每个处理均施磷(P) 800 mg/kg土。移栽10周后收获，分析生物量、磷积累量、根际土壤有效磷含量、有效株数、磷提取率、最大潜在收获量和最大磷去除潜力，以明晰不同追氮时期下两种生态型水蓼磷积累能力及土壤磷去除效果的差异。
    结果 与不施氮对照相比，追施氮肥处理均显著提高了两个生态型水蓼的生物量和磷积累量。ME地上部生物量和磷积累量在第8周追氮时达最大值，分别为52.11 g/plant和219.71 mg/plant，分别是不施氮的1.78和1.80倍，并显著高于NME。ME根际土壤有效磷含量在第6和8周追氮时增加，显著高于不施氮，同时也明显高于非根际土壤，有利于植株对磷的吸收积累。第8周追氮处理的ME地上部有效株数最小且明显低于NME，地上部磷提取率最大且明显高于NME，最大潜在收获量和最大磷去除潜力也最高。
    结论 追施氮肥促进了水蓼对根际土壤磷的活化和吸收，提高了水蓼的磷积累能力和土壤磷去除效果。移栽后第8周追氮提升矿山生态型水蓼磷积累能力和去除土壤磷的效果最明显，其地上部磷积累量和最大磷去除潜力分别达219.71 mg/plant和97.45 kg/hm2，并且矿山生态型磷提取能力高于非矿山生态型。

     

    Abstract:
    Objectives Nitrogen (N) fertilization enhances the phytoextraction efficiency of phosphorus (P) by plants. We investigated the effects of N topdressing stages on P accumulation and P removal efficiency in the P-accumulating plant, Polygonum hydropiper, to provide a scientific base for utilizing N fertilization to promote phytoremediation of soil P excess.
    Methods A soil-based pot experiment was conducted using mining ecotype (ME) and non-mining ecotype (NME) as study materials. Under the condition of N application at 100 mg per kg soil and a base-topdressing N ratio of 1∶1, five topdressing N stages were established, specifically at the 5th, 6th, 7th, 8th, and 9th weeks after transplantation. The treatment without N was used as the control (CK). P was applied at 800 mg per kg soil for all treatments. After 10 weeks after transplanting, the plants were harvested for investigation of biomass, P accumulation, and soil available P concentration. The plant effective number, P extraction ratio, maximum potential yield and maximum potential P removal were calculated.
    Results Compared with CK, all the N topdressing treatments increased the biomass and P accumulation of ME and NME plants. ME achieved maximum shoot biomass and P accumulation at the 8th week topdressing treatment, reaching 52.11 g/plant and 219.71 mg/plant, respectively, which were 1.78 and 1.80 times those of CK and significantly higher than those of NME. Rhizosphere soil available P concentration in ME increased significantly at the 6th and 8th week topdressing treatment, exceeding both the control and the non-rhizosphere soil value, facilitating P uptake. The 8th week topdressing treatment in ME yielded the lowest plant effective number (significantly lower than that of NME) but the highest aboveground P extraction rate (significantly higher than that of NME), along with peak values of both maximum potential yield and maximum potential P removal.
    Conclusions N topdressing enhanced P accumulation and P removal efficiency in Polygonum hydropiper by promoting rhizosphere P activation and absorption. The 8th week post-transplantation topdressing stage optimized ME’s P accumulation and soil P removal efficiency, with maximum shoot P accumulation (219.71 mg/plant) and maximum potential P removal (97.45 kg/hm²), and the P extraction capacity of ME was higher than that of NME.

     

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