• ISSN 1008-505X
  • CN 11-3996/S

关中平原冬小麦临界磷浓度稀释曲线的构建与磷营养诊断

Construction of critical phosphorus concentration dilution curve and phosphorus nutrition diagnosis of winter wheat in Guanzhong plain

    摘要
  • 摘要:
    目的 基于关中平原冬小麦施磷量与小麦磷营养的关系，建立临界磷浓度稀释曲线，为当地冬小麦科学施磷提供理论依据。
    方法 长期定位施磷田间试验始于2009年，供试小麦品种为‘西农979’。设置4个施磷水平(P2O5) 0、60、120、180 kg/hm2，分别记为P0、P60、P120和P180处理。于2018—2021年冬小麦拔节期、孕穗期、开花期、灌浆期和成熟期取样，分析冬小麦地上部生物量、植株磷浓度，记录小麦产量。利用2018—2020年冬小麦地上部生物量和植株磷含量建立临界磷浓度稀释模型，计算磷营养指数 (PNI)。依据2020—2021年冬小麦数据验证磷营养指数诊断的可靠性。
    结果 1) 施用磷肥可显著增加冬小麦穗数和穗粒数，显著降低千粒重，2018—2021年3季冬小麦依次提高穗数50.7%～53.0%、23.1%～29.7%和17.5%～19.0%，穗粒数依次提高28.6%～34.2%、22.7%～24.1%和18.7%～19.6%，千粒重依次降低1.1%～2.9%、3.5%～7.0%和1.3%～4.9%，P60、P120和P180处理间穗数、穗粒数(2018—2019年除外)差异不显著。随着施磷量增加，冬小麦籽粒产量先持续增高而后降低，施磷处理下2018—2021年3季冬小麦依次增产104.3%～108.2%、39.8%～47.4%和27.6%～32.5%，在P120处理下产量达到最大值，2018—2021年3季依次为7100、6369和6714 kg/hm2。2) 冬小麦地上部生物量随生育进程的推进逐渐增加，地上部磷浓度随生育进程推进逐渐降低。同一取样时期，施磷量增加，地上部生物量和磷浓度也随之增加。据此，本研究2019—2020年建立的临界磷浓度稀释曲线模型为Pc=6.00DM–0.43，模型RMSE值为0.09，n-RMSE值为3.45%，表明模型模拟值的可靠性和稳定性达到要求。3) 随着施磷量增加，磷营养指数 (PNI) 增大，磷营养指数 (PNI) 在P120处理下最接近1。各施磷量处理下，冬小麦磷营养指数 (PNI) 随生育期的变化较小。
    结论 依据不同施磷量下冬小麦地上部生物量和磷浓度，建立的临界磷浓度稀释曲线模型与磷营养指数 (PNI) 模型能够准确诊断关中平原冬小麦不同生育阶段的磷素盈亏状况，可用来指导关中平原冬小麦植株各生育期磷素含量评估和磷肥施用。

     

    Abstract:
    Objectives Based on the relationship between winter wheat phosphorus application rate and wheat phosphorus nutrition in Guanzhong Plain, we established a critical phosphorus concentration dilution curve to provide a theoretical basis for meeting the P needs of local winter wheat.
    Methods The long-term localization phosphorus field experiment was established in 2009, and the wheat variety was Xinong 979. The four phosphorus application treatments (P2O5) tested were 0, 60, 120, 180 kg/hm2, noted as P0, P60, P120 and P180, respectively. The above-ground plant samples were determined at the jointing, booting, flowering, filling, and maturity periods of the winter wheat from 2018 to 2021, and the above-ground biomass and plant phosphorus concentration were analyzed, the wheat yield was also evaluated. A critical phosphorus concentration dilution model was used to calculate the P nutrient index (PNI). The reliability of phospho-nutrition index was verified based on winter wheat data from 2020 to 2021.
    Results 1) P fertilization significantly increased the panicle number in three seasons by 50.7%–53.0%, 23.1%–29.7%, and 17.5%–19.0%, increased the grain number per panicle by 28.6%–34.2%, 22.7%–24.1% and 18.7%–19.6%, but reduced 1000-grain weight by 1.1%–2.9%, 3.5%–7.0% and 1.3%–4.9%, respectively. The panicle number elicited by P120 and P180 treatments were similar. With the increase in P application rate, the grain yield increased first and then decreased, and the yield in the three seasons was increased by 104.3%–108.2%, 39.8%–47.4%, and 27.6%–32.5% on average, with the maximum yield of 7100 kg/hm2, 6369 kg/hm2, and 6714 kg/hm2 under the P120 treatment. 2) The aboveground biomass of winter wheat gradually increased with the progress in the growth process, and the P concentration in the upper aboveground part gradually decreased. Based on the aboveground biomass and P concentration of winter wheat in 2019—2020, a critical P concentration dilution curve model was established: Pc=6.00DM–0.43, with the RMSE of 0.09, and n-RMSE of 3.45%, indicating that the reliability and stability of the model simulation values meet the requirements. 3) The PNI of wheat was mainly affected by P application rate, not by growing stage. P120 treatment had the PNI closest to 1.
    Conclusions Based on above-ground biomass and P concentration of winter wheat under different P application rates, the critical phosphorus concentration dilution curve model and P nutrition index (PNI) model can ideally diagnose the status of phosphorus, balance in winter wheat in Guanzhong plain, and can be used as a tool for phosphorus content assessment and guidance of phosphorus fertilizer application.

     

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