B.GBP.0063 - Phosphorus Map of Queensland Grazing Lands 2
Many Australian soils are known to be inherently low in available P and can result in P deficiency in grazing cattle. Without sufficient P, overall cattle health can be significantly impacted and overall productivity reduced.
| Project start date: | 23 June 2023 |
| Project end date: | 02 June 2025 |
| Publication date: | 28 November 2024 |
| Project status: | In progress |
| Livestock species: | Grass-fed Cattle, Sheep, Goat |
| Relevant regions: | Queensland |
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Summary
Graziers often resort to phosphorus (P) supplementation to overcome P deficiency and rely on soil maps to inform them of the P status of their lands. A digital map of soil P was recently produced to inform on P status but did not extend into the Gulf and Cape York regions of Queensland, where a significant portion of the state’s grazing land exists and are known to be P-deficient. The outcomes of this project will fill that gap and update the existing map, therefore providing graziers with access to high-resolution soil P information to inform P management strategies across all of Queensland. This will result in greater productivity and profitability across the red meat industry.
Objectives
The overall aim of this project was to update and extend the soil P map into the northern regions of Queensland. The specific objectives were to:
1. review the existing soil P datasets available for the entire extent of Queensland
2. review current availability of soil P data from the northern regions of Queensland
3. identify geographical gaps in the data set and collect/analyse new samples
4. update the previous digital soil mapping methodology with new machine learning models and spatial covariates
5. produce a predicted soil P (0–10cm) map of Queensland at a 30m resolution
6. incorporate the map into extension materials (e.g. upload to the LongPaddock website).
Key findings
A total of 6,796 unique site location samples were identified across Queensland as suitable for modelling following data cleaning. Of these, 228 samples were sourced in this project, either through soil sampling campaigns or archived data. The QRF model predicted soil P with a concordance correlation coefficient of 0.48, which is a 20% improvement compared to the previous soil P map. Final prediction maps including uncertainties (5th, 50th and 95th percentiles) were generated across Queensland at a 30m resolution.
Benefits to industry
The soil P map produced will provide general information to graziers regarding soil P status across their properties. The soil P map is indicative and should be complemented with site-specific soil tests to obtain accurate soil P levels. This will equip graziers with the knowledge necessary to refine P management for P-deficient soils, ultimately driving enhanced productivity and profitability in the red meat sector.
MLA action
The updated P Map produced as part of this project will be made available across various MLA resources, providing graziers with access to high-resolution soil P information to inform P management strategies across all of Queensland.
Future research
Several future research directions were identified in this project including:
(i) the creation of a P buffering index map to complement the soil P map, which provides information on the soils capacity to adsorb and hold onto P
(ii) extension of the updated mapping methodology into the northern regions of Australia, including the Northern Territory and Western Australia which are known to be P-deficient
(iii) areas of high uncertainty where future sampling campaigns could be targeted to improve model predictions and reduce uncertainty.
More information
| Project manager: | Sarah Hassall |
| Contact email: | reports@mla.com.au |
| Primary researcher: | Queensland Government |
