Biological amelioration of subsoil acidity via excess anion uptake by wheat

Zhe Weng, Peter Sale, Guangdi Li, Caixian Tang

    Research output: Book chapter/Published conference paperConference paperpeer-review

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    Excess anion uptake in the form of nitrate has been shown to reduce soil acidification at depth. This root-induced alkalization of rhizosphere soil can be extended to bulk soil. This study investigated ways to maximize the alkalinizing effect of calcium nitrate in reducing subsoil acidity in wheat (ET8) and canola (44Y90). A controlled environment experiment was carried out over 35 days. A Chromosol with topsoil (0-8 cm, pHCaCl25.4 and 1.5 mg Al kg-1) and subsurface soil (8-15 cm, pHCaCl2 4.8 and 2.9 mg Al kg-1) layers was used. The soil was reconstructed as 0-10 cm topsoil and 10-50 cm subsurface soil in columns (15 cm in diameter, 60 cm in height). Air-dried soils (<2 mm) were treated with three N fertilizers: 1) control, 2) urea and 3) Ca(NO3)2 with and without phosphorus fertilizer at three depths: 1) 0-10 cm, 2) 10-20 cm and 3) 20-30 cm. All N and P fertilizers were applied at 134 kg N ha-1 and 56 kg P ha-1 at sowing. Uptake of Ca(NO3)2 increased pH up to 0.2 units of bulk soil in the 0-10 cm layer compared with the urea application regardless of the placement of the treatments. Rhizosphere alkalization was greater at the depth where nitrate and P were combined compared with those with the urea treatment. We highlighted the importance of balancing nutrient supply at depth in encouraging anion uptake by plants, which enhances rhizosphere alkalization in acid subsoil.
    Original languageEnglish
    Title of host publicationProceedings of the 19th Australian Agronomy Conference
    Place of PublicationWagga Wagga
    PublisherAustralian Society of Agronomy
    Number of pages4
    Publication statusPublished - 2019
    Event19th Australian Agronomy Conference 2019 - Wagga Wagga Civic Theatre, Wagga Wagga, Australia
    Duration: 25 Aug 201929 Aug 2019 (Conference website) (Conference program)


    Conference19th Australian Agronomy Conference 2019
    Abbreviated titleCells to Satellites
    CityWagga Wagga
    OtherThe 19th Australian Agronomy Conference will be held in Wagga Wagga, NSW from 25 – 29 August 2019. In the heart of the Riverina, Wagga Wagga has a range of rural industries across the region. Wagga has everything to offer the agronomy conference being surrounded by a mixed farming zone with irrigation to the west and permanent pasture enterprises to the east.
    The conference theme Cells to satellites highlights the integrative nature of agronomy. Each of us work across a range of disciplines to optimise crop or pasture production for productivity and profitability. We have an increasing number of tools available to increase the precision and accuracy of our work; whether it is at the “cellular” level where DNA is mapped and biochemistry is unravelled or using “satellites” for remote sensing or guidance. The opportunities for enhancing our agronomy research is boundless.
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    Grant Number

    • DAN00206


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