Jerramungup Nutrition Trial

Timeframe: 2012 to 2017

Funding source: Grains Research Development Corporation (2012), South Coast NRM (2013, 2016), FBG (2013, 2015)

Project Coordinator: Karryn Dorrell.

Technical support: DAFWA

Summary

The FBG nutrition trial started as a lime application trial in 2012. Such was the interest in it that the decision was made to continue it for another four years and to compare four different commercial nutrition treatments to determine if any of them could achieve similar results in the absence of lime.

Consistently over the five years of the trial, the limed (farmer treatment) plots continued to perform well and grossed the highest combined income of all of the treatments. The trial reinforced the long-term benefit of applying lime as a part of the farm fertiliser program.

This project was the first long-term trial of its kind carried out by the FBG and a lot was learned from the process. The trial was initially designed to run for one year. When the decision was made to continue it for four more and to change the scope, the overall project design, the budget and the trial layout, all ideally should have been reassessed. Limitations to both budget and design impacted on the project’s success and the robustness of the results.

Project details and outcomes

The site of this trial was located 10 km east of Jerramungup, at Trent and Tina Parsons. It is primarily sandy gravel and loamy sand at 15 cm plus.

There were four fertiliser strategies compared in this trial: the farmer’s own practice and three commercial treatments. The farmer practice plots were the only ones to receive a 2t lime application, which occurred in the first year (2012).

The trial layout consisted of four plots set out in a randomised pattern and replicated three times, for a total of 12. Each plot was seeded at the same time, with the same machinery, at the same rate, with the same chemicals and with the same variety to make the differences in plot treatments comparable. The rotation was wheat, barley, peas, canola, wheat.

Measures carried out throughout the trial included: soil pH tests, germination counts, tissue tests and root to shoot weights and ratios. Harvest yields were recorded on a per plot basis rather than aggregating the results from plots with the same treatments. This served to highlight variability between plots. Statistical analysis of the yields was carried out by DPIRD staff. An economic review was also carried out to determine gross margins per treatment type.

The trial limitations (discussed below) may have affected the results. The most conclusive result was that the limed fertiliser plot (farmer practise) consistently performed well and grossed the highest combined income of all of the treatments across the five years.

This trial was one of the first in Western Australia to compare as many different fertiliser strategies and philosophies. It highlighted that success can be achieved by several different methods, depending on each farmers’ production and soil health goals.

In hindsight, there are several things that could have been done better. When the decision was made to continue the trial after the first year, the trial design should ideally have been re-assessed. Considerations include: adding at least one more replication and including several controls within each replication.

Inconsistent funding streams, including two years without an external funding source, meant the project was not properly resourced. This affected most aspects of the project, including coordination, timing and communications.

Over the five-year lifespan of the trial it was visited by more than 200 individuals, with many visiting annually to gain further insights. Most farmers said they wanted long term trials to continue as they can more accurately measure the effects they themselves are seeing within their own businesses and in their own soils. The biggest limitation to this is securing long term funding.

The FBG fertiliser trial started as a lime application trial in 2012 and ultimately finished as one as well. In 2012 the aim was to determine if any fertiliser treatment sans lime could help achieve the same or similar results. As the project turned into a long-term trial on fertiliser treatments it became more evident that there is a long-term benefit to applying lime as a part of the farm fertiliser program. Consistently over the five years of the trial, the limed fertiliser plot continued to perform well and grossed the highest combined income of all of the treatments for the whole of the five years.