NRCMA Case Study: Simplifying Compost Tea Application
Location
Hastings Valley
Duration
Trial commenced February 2010, to be completed October 2010.
Project partners
Hastings Landcare, local farmers FoodPrints and Koree Herbs.
Objective
We aim to save time, fuel and money whilst improving the soil, increasing agricultural productivity and improve awareness of biological farming methods by demonstrating and testing simplified and more cost effective methods of application of aerated compost tea.
Description
Two farms in the valley representing pastured beef and horticulture are experimenting with methods of applying aerated compost tea. The application of compost tea (containing live micro-organisms) to the soil can improve nutrient cycling, soil structure, water holding capacity and carbon content. To protect microbes from solar radiation and desiccation, compost tea is usually sprayed on at night or during the rain. We have modified existing farming equipment to apply compost tea during the day at the same time as routine farming jobs.
The equipment modifications are deliberately low-tech and inexpensive. The project collected and analysed biophysical data to test the hypothesis that there is no difference between: spraying compost tea on crops and pastures at night; and incorporating compost tea into routine farm operations during the day.
Sharing information and enthusiasm about soil biology. Photos: Cathy Eggert 2010.
Thatch breakdown 14 days after mulching with compost tea (left) and mulching without compost tea (right).
Microscope photos: Jeremy Bradley 2010.
Project outputs
Results suggest that incorporating compost tea during day-time pasture mulching and injection during pasture renovation with a subsoil plough are effective techniques for introducing microorganisms. Measures of mulch breakdown, microorganism content of the soil and pasture production did not show a statistically significant difference between spraying and modified equipment application methods. In a trial simulating application of compost tea on mulched pasture, there was no statistically significant difference in mulch breakdown and pasture regrowth between the untreated control and the spray and mulcher application treatments.
In garlic, where compost tea was incorporated at planting and sprayed on throughout the growing season, a significantly higher silicon content was found in leaf samples. At harvest, soil foodweb analyses showed no significant difference between the treated and untreated soils.
However, improvements in productivity and soil structure are visually discernible in the compost tea treated pasture, garlic and herb crops.
NRM outcomes
Aerated compost tea application can enhance the biodiversity of the soil and improve soil structure, water holding capacity, nutrient cycling, disease suppression and soil carbon sequestration. This project raises awareness of biological farming and removes barriers to adoption by making compost tea application less expensive and more convenient.
Following field days in May and October, all participants said they would apply information and techniques learned to their own farming operations. Strong interest has been expressed in modifying equipment to incorporate compost tea into the farming routine. People are keen to learn more about soil biology and we predict that interest in and adoption of biological farming will continue to grow in this valley. Project cost In excess of $60,000, including Landholder contributions
Funding source
Northern Rivers Catchment Management Authority provided $29,980
For further information
A PlaceStory of the trial this can be seen at http://ps3beta.com/story/15728
Hastings Landcare Inc. 02 65864465