DairyTas on-farm change projects

1. DairyTas Riparian and Shelterbelt Projects

On farm works (Envirofund)

DairyTas was successful with two Envirofund funded projects from the last round (announced October 2007). These are titled ‘Improving water quality and biodiversity in Mowbray Swamp’ and ‘Improving water quality and biodiversity in Togari/Brittons Swamp’. 

Agricultural Resource Management has been engaged to co-ordinate the projects, which involve a combination of planting of native shelterbelts/riparian vegetation and fencing of waterways and bush areas to exclude stock. 8 dairy farms in the Circular Head region are involved with the projects.

The projects are progressing well, with all of the plantings (including some excellent site preparation by the landholders) and most of the fencing works complete in Mowbray Swamp, with the remainder set to be completed by early 2009. Planting for Togari and Brittons Swamp area farms is now scheduled for autumn 2009, giving the landholders plenty of time to get some good site preparation completed. 

The outcomes of these projects will be increased biodiversity, less nutrient inputs to waterways, and improved production through increased stock shelter.

2. Water Use and Nutrient Management Project

Farm Monitoring (NLP funded)

Seventeen dairy farms located in the South, North-East and North-West of Tasmania are currently involved in the final year of this three year study. The project is being run by the TIAR Dairy Centre for DairyTas. Commercial dairy farms located in the Derwent Valley (4 farms), Ringarooma (7 farms) and Flowerdale (6 farms) regions are involved with the monitoring of water use, pasture production and soil fertility as part of this study.

Hansen data loggers monitored soil moisture and temperature (°C) at each site, with 3 gypsum blocks installed at depths of 15, 35 and 50 cm. Loggers recorded soil moisture and temperature every 4 hours. The use of Hansen loggers, with a built-in display, allows for immediate recognition of soil moisture levels and provides farmers with the information required to adjust rates of irrigation accordingly. Generally, farmers continued to maintain soil moisture potential within the optimum range of 10-35 cb to maximise pasture production and reduce the risk of yield reduction due to a soil moisture deficit.

Each of the seventeen sites was re-sampled for soil fertility assessment in July and August 2007. Approximately 30 soil samples were taken from five paddocks following the 1st years sampling. Samples were analysed for phosphorus [(P) Colwell and Olsen], potassium (K), KCl sulphur (S), pH (1:5 CaCl2) and electrical conductivity.

Year 1 and year 2 were compared. Farmer response to soil analysis results has been encouraging, with farms continuing their efforts to meet the optimum agronomic ranges for P, K and S. Soil fertility was of particular interest to the farmers, with the majority indicating the economic gain they achieved from their soil analysis for fertiliser inputs.

3. Dairy Effluent Management Projects

On Farm Works (NHT and NLP funded)

DairyTas is currently delivering round 3 and 4 of the effluent management program. By the end of 2008 over 160 dairy farms (over 30% of the industry) will have upgraded their systems to meet best practice in the context of the farm management resources and the management of the effluent on the property. This is over the 4 years since the project commenced operation.

Farmers have invested an average of $16,000 in on ground works, a total investment of over $2.5M.

The project involves approved farms having an effluent management plan prepared by the projects technical consultants, David Armstrong and Robin Badcock. The farmers then undertake on ground works to upgrade their effluent management system on a $ for $ basis for up to $5,000.

Farm works undertaken include items such as effluent storage dams, sand and gravel traps, solids separation systems, irrigation equipment, pipework and the like.

The project has made significant progress in assisting dairy farmers to eliminate the risk of effluent leaving the property and inpacting on waterways and water quality. Many farmers are now able to utilise more effectively the nutrient value of the dairy effluent on their farm.

4. Alternatives to the Use of 1080 Project – Impacts of wildlife Browsing on Pastures in Tasmania

The Tasmanian Institute of Agricultural Research (TIAR) was contracted in 2007 to undertake a three year research project entitled ‘New decision support tools to quantify and monitor the impact of herbivory of native wildlife on pastures & identify alternative control mechanisms’. Funding from the project is provided under the ‘Alternatives to the Use of 1080 Program’.

The study aims to quantify and monitor the impact of herbivory (“browsing damage”) by native marsupial species and game on native and introduced pastures supporting agricultural production (eg. dairy, beef, sheep) in Tasmania. The intention is to achieve the aims by using a combination of spatially-explicit models of herbivore population density and predictive pasture growth models coupled with quantitative field measurements of herbivore population density and in-situ estimates of herbivory and pasture production.

Findings to date: Native wildlife browsing can have a significant impact on pasture production, with the economic cost likely to be significant. Pasture percentage loss expressed as kg DM/ha due to wildlife browsing varied according to system (the extent of differential browsing impacts in irrigated versus dryland pastures is unclear at present), location, and wildlife abundance at all 12 sites. Pasture loss to wildlife browsing ranged from 12 to 100%, with an average of 65% over the 12 sites for the six month monitoring period.

‘Edge effects’ were evidence at all 12 of the main sites, with browsing generally higher near the bush line. The higher the abundance of wildlife, the greater the likelihood of browsing impacts away from the ‘edge’. Edge effects can influence both pasture production and pasture species composition, however the full nature and degree of preferential browsing is currently unclear.

Wildlife management may be one of the most important factors influencing production and profitability. It is important to have an adequate understanding of wildlife number and movements/impacts on a property. While wallaby proof fencing has been proven to be effective, we have yet to test the benefits and costs on both an environmental and economic level. The research is ongoing to 2010.