Investment
Investment
GRDC Code: DAQ2307-001RTX
NGN - Understanding the long term residual benefit of deep placed P in south west and central Queensland
This project aims to investigate the benefits of deep placement of phosphorus (P) fertiliser in subsoil layers to enhance crop recovery and yield. The research aims to determine the duration of the residual benefit of deep P placement and provide cost-effective implementation strategies for growers.
Macronutrient imbalances, particularly negative balances of nitrogen (N), phosphorus (P), potassium (K), and sulphur (S), have been observed in the northern grains region. Nutrient depletion in the soil has led to increased fertiliser applications, primarily N and P. While N fertilisers are traditionally applied pre-plant, a smaller amount of P is applied as a starter application with seed at sowing. However, crop requirements exceed what can be met through starter P fertilisation alone or root uptake from the top soil layer. Nutrient extraction from subsoil layers has resulted in surface P stratification, creating a difference in plant availability between enriched surface layers and depleted sub-surface layers.
Research (UQ00078) has shown that placing immobile nutrients like P in subsoil layers, where roots are abundant and soil moisture availability is sufficient, can lead to significant yield responses. However, the duration of the residual benefit of deep P placement remains unknown. The opportunity exists to retest sites from the UQ00063 investment, established between 2013-2016 and monitored for up to 6 years post-application, to determine if there is still a residual benefit after 6-10 years. Utilizing sites with the most available data is recommended for further research.
Outcomes:
1. Determine the length of residual P benefit in crops after deep placement of P fertiliser.
2. Conduct cost/benefit analysis based on the amount of fertiliser applied and the time frame until reapplication is required.
3. Provide implementation strategies for growers based on the estimation of residual P benefit to optimise fertiliser usage and improve crop yield.
Macronutrient imbalances, particularly negative balances of nitrogen (N), phosphorus (P), potassium (K), and sulphur (S), have been observed in the northern grains region. Nutrient depletion in the soil has led to increased fertiliser applications, primarily N and P. While N fertilisers are traditionally applied pre-plant, a smaller amount of P is applied as a starter application with seed at sowing. However, crop requirements exceed what can be met through starter P fertilisation alone or root uptake from the top soil layer. Nutrient extraction from subsoil layers has resulted in surface P stratification, creating a difference in plant availability between enriched surface layers and depleted sub-surface layers.
Research (UQ00078) has shown that placing immobile nutrients like P in subsoil layers, where roots are abundant and soil moisture availability is sufficient, can lead to significant yield responses. However, the duration of the residual benefit of deep P placement remains unknown. The opportunity exists to retest sites from the UQ00063 investment, established between 2013-2016 and monitored for up to 6 years post-application, to determine if there is still a residual benefit after 6-10 years. Utilizing sites with the most available data is recommended for further research.
Outcomes:
1. Determine the length of residual P benefit in crops after deep placement of P fertiliser.
2. Conduct cost/benefit analysis based on the amount of fertiliser applied and the time frame until reapplication is required.
3. Provide implementation strategies for growers based on the estimation of residual P benefit to optimise fertiliser usage and improve crop yield.
- Project start date:
- 25/09/2023
- Project end date:
- 30/06/2026
- Crop type:
-
- Wheat, (Cereal)
- Barley, (Cereal)
- Sorghum, (Cereal)
- Organisation
- Queensland Department of Agriculture and Fisheries
- Region:
- North
- Project status
-
Active