Please use this identifier to cite or link to this item: https://hdl.handle.net/1959.11/63390
Title: The effect of pH and PBI on the critical phosphorus requirements of two tropical pasture species
Contributor(s): Mclachlan, Jonathan W  (author)orcid ; Gunadasa, Sajanee G  (author)orcid ; Flavel, Richard J  (author)orcid ; Guppy, Chris N  (author)orcid 
Publication Date: 2024-10
Open Access: Yes
Handle Link: https://hdl.handle.net/1959.11/63390
Open Access Link: https://www.agronomyaustraliaproceedings.org/images/sampledata/2024/2024ASAmclachlan_jonathan_2-98-839-McLachlan-Jonathan.pdfOpen Access Link
Abstract: 

Tropical pasture species are often grown in soils with available phosphorus (P) concentrations below their critical P requirements. However, little is known about how key soil traits such as pH and Phosphorus Buffering Index (PBI) influence the critical P requirements of these species. Two controlled-environment experiments were conducted to investigate the effect of different starting pH and PBI on the shoot yield and P acquisition of Digit and Desmanthus. In the first experiment, the two species were grown in low-P soil that was amended to achieve five soil pH treatments (4, 5, 6, 7 and 8). In the second experiment, the two species were grown in a low-P soil mix that contained varying combinations of a low-PBI soil and a high-PBI soil to achieve five soil PBI treatments (65, 145, 225, 305 and 385). Ten soil P treatments (0–120 mg P kg–1 ) were prepared by adding KH2PO4 solution to the soil surface. The shoot yields of Digit and Desmanthus increased in response to the higher application rates of P in both experiments. In the soil pH experiment, both species were most productive in the pH 5–8 treatments. Critical external P requirements were lowest in the pH 7 treatment and increased at lower and higher pH levels. In the soil PBI experiment, critical external P requirements increased significantly with PBI. Nevertheless, critical internal P requirements remained relatively stable. Tissue P tests may therefore be a useful way to determine likely responses of tropical pasture species to P fertiliser application across a range of soil types.

Publication Type: Conference Publication
Conference Details: AAC2024: Australian Agronomy Conference, Albany, Australia, 21st-24th October, 2024
Source of Publication: p. 1-4
Publisher: Australian Society of Agronomy
Place of Publication: Australia
Fields of Research (FoR) 2020: 300407 Crop and pasture nutrition
300403 Agronomy
410604 Soil chemistry and soil carbon sequestration (excl. carbon sequestration science)
Socio-Economic Objective (SEO) 2020: 100505 Sown pastures (excl. lucerne)
Peer Reviewed: Yes
HERDC Category Description: E1 Refereed Scholarly Conference Publication
Publisher/associated links: https://www.agronomyaustraliaproceedings.org/index.php/2024-proceedings
Appears in Collections:Conference Publication
School of Environmental and Rural Science

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