On-farm trials and evaluations are an important tool in the nutrient management toolbox.
Allow a grower to compare new practices, products or rates under the circumstances and conditions in which they farm
Valuable and preferred method for fine tuning nutrient management practices
Positive outcomes from on-farm trials help build confidence in a new practice
They should be used if a grower is unsure whether a practice will work on their farm, if they are unfamiliar with a new practice or product, or if there is concern that a practice may have a negative outcome (productivity or profitability).
When implementing an on-farm trial it is important to consider the following points:
Seek advice on design and implementation from a trusted advisor prior to commencing any trial and again when interpreting results
Ensure the mill and harvesting contractor are aware of the trial
Mills can provide information on how much cane is required in a rake (often 30-40 t) to receive a separate CCS analysis. This affects the area required in any treatment (row length, number of rows, likely yield)
Keep it simple – only change one practice at a time and compare it to your current practice (control) – new product applied/no product applied (control) or new nutrient rate/ current nutrient rate (control)
If testing lower nutrient rates, start by making small adjustments (~10% reduction)
Variety, crop class and all other management practices should be the same across the whole trial area
Soil type should be as uniform as possible, EM mapping will assist in site selection
Variable blocks may require more complex trial designs. Consult an experienced advisor
Ensure there are replicates of each treatment (three or four separate sections of a block receive the same treatment). Subtle changes in soils, moisture content, irrigation efficiency, weed and pest pressure can cause yields to vary across a block. Replicates help reduce the effect of these factors on trial results
Avoid simply dividing a block into two and treating each half differently, or comparing two separate blocks
Keep a record of factors likely to have affected the results (rainfall, irrigation, other)
At harvest, consign the areas that received different treatments separately
Compare cane yield, CCS and sugar yield to identify whether there was any change in production due to the new practice
A simple gross margin assessment will assist in determining whether a new practice had an economic benefit. A simple gross margin calculator has been included below.
