A trial that mimics what farmers would experience by buying alternative fertilisers has initially shown they can have a positive impact - but economic assessment is still to come.

“A roll-up of 60 people to our Bookham field day highlights the interest and relevance of this work to the farming community,” said Yass district agronomist, Fiona Leech.

“It is worth highlighting that manure and compost based products can be highly variable in both nutrient and dry matter content, so buyers must consider this before purchasing,” she said.

“Some products may take a number of years to induce change, so it’s important to wait for our final year of results before attempting to draw any conclusions.

“At the conclusion of the trial, we’ll do an economic assessment on the cost effectiveness of each product, judged by pasture grown in the spring testing period.”

A third and final year of data will be collected in the coming 2011 spring.

Field day participants came to Bookham to discuss the first two years’ worth of pasture and soil test results from the Native Pasture Alternative Fertiliser Trial, initiated by Binalong Landcare with technical support from the NSW Department of Primary Industries (DPI). 

Three native pasture sites in the Binalong and Bookham areas are trialling 10 products, applied at rates determined by the fertiliser companies involved, which they based on soil test results from the trial plots.

The 10 products are single super, agriash, Eco-min Balance, SEP pig manure, DECC Compost, YLAD compost mineral blend, YLAD compost tea, urea, BioAg Superb and Ecology fluid fertiliser/Dical 64. 

A control or nil treatment plot is also included.

Fiona Leech (pictured far right in red top) is coordinating the field research work, with support from NSW DPI colleagues.

Pasture growth measurements are taken once a year in spring.

“We chose spring because it’s usually when moisture and temperature are not limiting production, and data collection then reliably indicates whether or not a fertiliser product is causing an increase in pasture growth,” Ms Leech said.

“Soil sampling occurs to a depth of 10 centimetres.

“Results indicate that some alternative fertilisers can have a positive impact on soil nutrient status and spring herbage mass.

“Products like agriash, pig manure, YLAD compost mineral blend and BioAg Superb have already shown some positive increases in pasture growth.

“Increases in spring herbage mass for some products appear to be highly correlated to increases in soil phosphorous and sulphur, as these are two of the most limiting soil nutrients.

“Current soil microbial activity appears to be more influenced by soil moisture levels than individual products at this stage.”

Some of the fertiliser products have been applied as capital dressings, designed to last for a number of years.

Ms Leech hopes the trial will help determine how often these products should be applied to obtain maximum benefit.

“It has not been possible to measure year round pasture production from the sites, however the spring pasture growth measurements will provide us with a relative index to the cost effectiveness of each product,” she said.

The trial has been funded by NSW DPI, Office of Environment and Heritage, Murrumbidgee Catchment Management Authority, Caring for our Country, Woolworths and Landcare Australia.

An interim report is available, highlighting the pasture and soil test results collected so far.

Contact Fiona Leech, Yass (02) 6226 2199, fiona.leech@industry.nsw.gov.au