A new uPtake trial has just been sown and fertilised in May in the Peel-Harvey.
The new trial site on a property in west Waroona has low phosphorus fertility, and low ability to retain phosphorus (P) in its soil. The trial has been fertilised with different application rates of superphosphate and basal nutrients.
The response in pasture growth will be analysed with pasture cuts throughout the growing season. It is anticipated that the pasture will show a response to phosphorus along a predicted phosphorus curve, which will peak at the “critical value” and then flatten to indicate that any extra amount of phosphorus added to the soil will be wasted.
The phosphorus curve is a reliable tool to help farmers understand at what point the addition of any more phosphorus will be in exceedance to their soils and plants ability to retain and use it. Any extra is a waste of money and a waste that enters waterways.
A field day will be planned in Spring for farmers to attend and see the results of the trial.
Thirty-two uPtake trials have now been implemented across the south-west over the last 4 years. All 32 uPtake trial results to date are consistent with national Better Fertiliser Decisions for Pastures (BFDP) data(i.e. trial results were within 20% of the predicted response) demonstrating the national data is relevant to SW WA conditions. For more information on BFDP click here: https://www.asris.csiro.au/downloads/BFD/Making%20Better%20Fertiliser%20Decisions%20for%20Grazed%20Pastures%20in%20Australia.pdf
So, what does this mean to me as a farmer?
- Results from trials to date show that the national critical values for P used to inform P fertiliser recommendations are relevant to SW WA. You can therefore have confidence that P fertiliser recommendations based on critical values from BFDP are appropriate.
- If your soil test shows that your soil contains excess P for your target production levels, (i.e Fertility Index greater than 1) adding more P will not increase productivity. Adding more P will unnecessarily increase costs and may escalate P movement into waterways, contributing to algal blooms. If your P soil test shows a Fertility Index of 1 at the start of the season, then it should contain sufficient P for seasonal pasture growth. Soil testing should guide subsequent pasture P requirements.
- Addressing limiting nutrients in your soil (e.g. nitrogen, sulphur, potassium, micro nutrients) and correcting low pH can dramatically increase production and minimise unnecessary losses of nutrients to the environment.
- Soil testing and comparison with critical values is essential to determine the nutrient requirements of your soil to meet your production targets.
For more information on the uPtake trials head to https://estuaries.dwer.wa.gov.au/uptake/ or you can contact Megan LeRoy on 6369 8800 or firstname.lastname@example.org
This project is supported by PHCC in partnership with DWER with funding from the National Landcare Program’s Smart Farming Partnership Project.