DairyTas R&D Projects

Dairy Effluent Management Program

 2008/09 saw the completion of the Dairy Effluent Management Project after 4 years operation across all Tasmanian dairy regions. Around 160 dairy farms participated in the program and invested around $2.5M on farm. Australian Government funds of $1.34M were provided over this period with around $800,000 going towards the farm on ground works component of the project.

Duck River Nutrient Budgeting Project

TIAR is delivering this project with dairy farmers in the Duck River catchment, funded by the Australian Government’s Caring for our Country initiative. 2008/09 was the first year of the project.

The project aims to assist the farmers with on-farm nutrient mapping and through farmer focus groups will assess a broad range of environmental priorities and resources. Farm specific nutrient budgets will be produced to gain improved information on nutrient management and farm inputs. Farm nutrient maps will identify nutrient hot spots and deficiencies so that application of fertiliser is better targeted and the risk of nutrient losses to waterways is minimised.

The project is running over 2 years with 15-18 farms each year participating in the project.

Nutrient Management Summary

·       70% of the farms sampled, returned an average soil result above the optimal range for pasture growth for phosphorous, potassium and sulphur

·       The catchment average for soil phosphorous, potassium and sulphur is also above optimal

·       Flat country farms are higher in phosphorous (above opt >30mg/kg) than hill country farms on average, which are within the optimal range (20-30mg/kg)

·       Hill country farms are higher in potassium and sulphur than flat country farms, both above optimal

·       16 out of 17 farms have an average pH within the optimal range (5.5-7), the catchment average also falls within the optimal range

·       Both hill and flat country farms fall within the optimal pH range, with hill farms slightly more acidic than flat country farms

·       Large on-farm variability (between paddocks) exists for soil phosphorous and potassium – less so for soil sulphur and pH.

Envirofund Projects

In 2007/08 DairyTas received funding from the Australian Government’s Envirofund Program for 2 projects in Northwest Tasmania to support waterway fencing and Revegetation on dairy farms. Both projects were subcontracted to Agricultural Resource Management to deliver.

The first of these was Improving Water Quality and Biodiversity in the Mowbray Swamp, was for $42,480 and involved 4 farms in the Mella, Smithton and Nabagena areas. The second project

was based in the Togari/Brittons Swamp area, with funds of $31,520 with another 4 dairy farms involved. Both of these projects will be completed in 2009.

OTHER PROJECTS IN TASMANIA

 1. Investigating the potential of deficit irrigation strategies to improve the efficiency of water use in irrigated temperate pastures. Research (Small Project Grants)

The TIAR Dairy Centre have undertaken a range of research and monitoring studies investigating water use efficiency on commercial farms and the potential pasture production from best management irrigation strategies. This work has been valuable in assessing the amount of water required to maximise pasture production on farm and how this can be effectively achieved. However, little research has been undertaken to examine how farmers can best water their pasture when water becomes a limiting resource.

Modelling work undertaken at TIAR has identified that a deficit irrigation strategy in a temperate climate can significantly improve water use efficiency of temperate pastures species. A deficit irrigation strategy is aimed at applying a percentage of the rainfall deficit (rainfall - potential evapotranspiration) to make better use of summer rainfall.

A study undertaken in 2007/08, funded by DairyTas, monitored the pasture performance and water use efficiency from different deficit irrigation strategies and extended the outcomes of the study to differing soil types and regions by undertakings a series of modelling activities.  The study demonstrated that improvements in the average response to irrigation across the Australian dairy industry of 1 tonne DM/ML can be increased by 50 to 90% under a deficit irrigation approach.

A deficit irrigation approach maintains the pasture in a responsive state and makes more efficient use of any summer rainfall events. Modelling work undertaken as part of the study also indicated that the removal of edaphic limitations and maximising pasture growth significantly improves the marginal irrigation response of dairy pastures. When edaphic limitations are removed, a deficit irrigation approach could potentially result in a marginal irrigation response of 2.8 t DM/ML. This is a considerable improvement above the industry average response and these findings are viewed as being critical to improving the efficiency of irrigation water use within the Tasmanian dairy industry.

The study has also attracted a second year of funding to investigate the interactions between deficit irrigation strategies and nitrogen use efficiency which will be undertaken in 2008/09.

2. Whole farm systems analysis of greenhouse gas emission abatement strategies for dairy farms. Research (Dairy Australia and DAFF funded)

There are numerous options identified for greenhouse gas (GHG) emission abatement on dairy farms. Cumulatively these options may reduce GHG emissions by 20 to 30%. However, a review of the impacts and possible outcomes for different abatement options at a whole dairy system level has not been done. This is a necessary step for positioning each abatement technology and to prioritise further investment. In 2007 the TIAR dairy centre commenced a project, funded by the Australian Department of Agriculture, Fisheries and Forestry and Dairy Australia, to quantify the potential reduction in GHG emissions for selected abatement strategies from a farming systems viewpoint. 

The project is estimating how much methane, nitrous oxide and carbon dioxide is emitted from differing dairy farming systems using a series of accounting algorithms and assessing the impact of potential abatement options for each system. To undertake the analysis information such as milk yields, stock numbers, farm size, diet, fertiliser, diesel and electricity usage for a 12-month period is collated and GHG emissions per farm and per kg milk solid is estimated. 

This allows a comparison between farming systems to ascertain which aspects have the greatest impact and to also identify key areas for abatement.  As part of the project, a computer model has been developed that will allow individual farm details to be entered, with the model able to calculate the GHG emissions from each farm system. The model also allows for the examination of changing management practices has on farm emissions. 

3. Montagu Catchment Soil Phosphorous and Pasture Calibration
(DairyTas, Dairy Australia and TIAR).
Project began in January 2007 and will conclude in December 2009.

Main aims:

• To demonstrate a relationship between soil available phosphorus (P) concentrations and pasture production on Hydrosols.
• To better match soil fertiliser requirements with pasture growth in the Montagu catchment.
• To encourage additional soil testing to improve nutrient distribution.
• To reduce the risk of surface P run-off from hump and hollow drainage systems to surrounding waterways.

Progress:

Pasture yield measurements have been taken at 2 ½ - 3 leaf stage of ryegrass growth (every 26 - 50 days) for a 12 month period. Average dry matter yield across all plots was 19138 kg/ha (19.1 tonnes/ha) for the 12 month period of April 2007 to March 2008. There were differences in dry matter produced at different soil phosphorus concentrations Olsen P from 25 to 90, but analysis of the individual plot data using Anova found that the differences were not statistically significant (P>0.05).

Pasture production through the year (Figure 7) was greatest during the spring and summer months (September – January) and was least during winter (July/August) and late summer (February/March). The low pasture production in winter was thought to be due to a combination of low temperature and excess soil wetness.

The conclusion so far in this experiment, is that the different soil Phosphorus concentrations have produced no significant differences in dry matter pasture production.

4. Landscape Logic – A Tasmanian Perspective

The focus of Landscape Logic is to better organise knowledge and assumptions about links between management actions and environmental outcomes.

Objectives:

To establish water quality responses to changes in land use and land management, and how water quality in turn affects riverine and estuarine health and function.

Aims:

1. Identify relative impact of land use, land management and previous landscape interventions on water quality.

2. Provide new knowledge and improved assumptions about the responsiveness of river health to water quality as a result of historic changes in land resource parameters.

3. Provide new knowledge and improved assumptions about responsiveness of estuarine health to water quality as a result of historic changes in land resource parameters.

Approach:

1. Land use and land management change: At catchment scale, examine relationships between historic data on water quality and land use for multiple Tasmanian catchments, model nutrient and sediment outflows to characterise responses for local catchments by geomorphic settings, and model water quality response to land use using the model CMSS. At paddock and sub-catchment scale, relate historic satellite imagery and aerial photography to water quality data for case studies of interventions and record social and policy drivers for changes (e.g. riparian zone fencing & revegetation, stock crossings),

2. River health: Explore relationships between land use change, water quality and habitat characteristics and key components of river ecosystem health using existing data sets and field sampling. In the absence of good time series data, explore relationships between land use change, water quality and habitat characteristics and key components of river ecosystem health using space-for-time experiments (data from many catchments at one time with and without intervention rather than one or two catchments over long periods of time)

3. Estuarine health: Examine the relationship between landuse history (derived by the Spatial Information project team) and existing data on water quality, flow and estuarine health. Explore relationships between landuse at regional and catchment scales, water quality and quantity and a variety of indicators of estuarine health by re-visiting some of the 22 Tasmanian estuaries sampled in the mid-late 1990’s.

5. Synchronising Phosphorus Fertilisation with plant phosphorus demand: a tactic to reduce phosphorus transfer from land to water
(Australian Research Council, DairyTas, Impact Fertilisers Ltd and Roberts Ltd.)
The project started in September 2005 and will conclude in January 2010.

Summary

Phosphorus loss from intensive pasture systems is a major issue internationally due to the pollution and nutrient enrichment of water ways. This study will examine how a strategy of synchronising phosphorus (P) fertiliser to periods of high P demand in ryegrass (Lolium perenne) may be used to improve the efficiency of P uptake and there­by reduce P losses in surface runoff. Simple models will be used to identify the key risk factors associated with surface P loss in order to improve the sustainability of P fertiliser use in pasture systems.

Activities and progress

1. Three field sites were established on commercial dairy farms (Elliott, Mt Hicks and Togari) to represent a range of soil P sorption properties. These sites received a range of P fertiliser treatments to examine the effect of single application compared to smaller rates applied strategically throughout the growing season on pasture production, pasture P and soil P levels. The field component was completed in Jan 2008 and soil and pasture nutrient analysis has been completed by the laboratory and data have been analysed statistically. A full report will be provided to industry by the end of September 2008.

2. A rainfall simulation experiment has been established in the glasshouse at TIAR using the soil from the Togari field site. This study will investigate the effect of applying 40 kg P/ha in a single application to 3 applications of 13.3 kg P/ha on P losses in surface P runoff using a rainfall simulator. We will also investigate the effect of getting runoff on day 0, 3, 6, 12, 24 after fertiliser application, as there is a concern that the ‘danger period’ for P losses following P fertiliser application are much longer than the current ‘4 day’ recommendation, on some soil types. The rainfall simulations will start at the beginning of October (barring any unforeseeable issues) and will be completed before Christmas 2008.

3. The data from the rainfall simulations will be used to develop a P runoff risk model (in relation to P fertiliser application) for the Togari/Britton’s swamp area by using the 3 years of runoff data collected by the Montagu Water Quality Monitoring project (Greg Holz).

4. The data from the field study will be used to further develop the P modelling component in DairyMod.

6. Defining the Soil Phosphorus Maintenance requirement of Dairy Pasture Soils
(Dairy Australia, Incitec Pivot Ltd and Impact Fertilisers Ltd.)
The project started in April 2005 and it due to finish in June 2009.

Background

When farmers apply phosphorus (P) fertiliser, one of the most significant forms of loss is due to the soil P sorption/fixation processes. Limited research has indicated that the amount of P fertiliser required to satisfy the soils requirement for P (ie. P sorption reac­tions) represents a large proportion of P fertiliser recommendations (between 50-80%), yet the information available to determine soil P maintenance in Australian pasture soils, is almost non-existent. Defining the soil P maintenance requirements of pasture soils will have important environmental implications, as more accurate nutrient budgets will reduce the risk of over fertilisation and P loss from pasture systems.

Activities and progress

Seven field sites have been established around the north and north-west of Tasmania and maintenance P fertiliser is being applied and soils are being sampled every 6 months. It is important that soils are monitored over the longest time period possible before any firm maintenance recommendations are made, due to normal spatial and temporal variation which occurs with soils.

Preliminary results suggest that soil P maintenance requirements vary with soil type and soil P sorption/fixation capacity and that more P fertiliser is required to maintain stable P levels as the initial P level increases. For example, preliminary data suggests that a soil at Olsen P of 40 requires more P to maintain it at that level compared to an Olsen P of 15 mg/kg.

7. Accounting for Nutrients on Australian Dairy Farms
(Dairy Australia and others)
The project started in July 2006 and it due to finish on June 30, 2010.

Background

Accounting for Nutrients is a national project run out of the DPI at Ellinbank in VIC and involves significant activity in all the key dairy states (VIC, TAS, WA, SA, NSW and QLD). The project involves on-farm monitoring of nutrient flows on 44 dairy farms from around the country, in order to develop and validate a framework for nutrient accounting on dairy farms that will identify and provide opportunities to improve the profitability and efficiency of nutrient use and pasture production whilst identifying key areas of nutrient use efficiency and reducing nutrient losses to air, soil and water.

More specifically, the following outcomes and benefits will occur:

1. The Australian dairy industry adopts a uniform set of protocols for nutrient auditing that is based on the best current information and knowledge (longer term, this means an ‘Overseer’ type nutrient account approach).

2. Improvements in the profitability of dairy farms via an improved understanding of nutrient fluxes and accumulations and the influence of management on these.

3. Reductions in nutrient excess and accumulation that will contribute to reductions in the loss of nutrients to ground and surface waters (N&P) and the atmosphere (N)

Activities and progress

Tasmania is monitoring 4 farms as part of this project and to-date, 3 farm visits have been undertaken and a nutrient audit of all nutrient stores on these farms has been conducted (i.e. the amount of nutrients currently on farm in the form of hay/silage, grain, effluent etc).

Data available to date includes a profile of the fertiliser use, farm characteristics, effluent systems, feed systems and farm maps for the 44 farms and feed analysis from selected farms. Most of the states will be soil sampling their farms in spring/summer 2008 and this will provide an interesting profile of soil nutrient distribution from different states around the country.

Water Use and Nutrient Management Project

2008/09 saw the completion of this project funded by the National Landcare Program and delivered by the TIAR Dairy Centre. The project involved 17 dairy farms in Flowerdale, Ringarooma and the Derwent Valley.

The results from this project suggest that soil concentrations of P, K and S are above the desired optimum agronomic range.

Over the period of the project there was a moderate decrease in soil P from an average of 36 (2006) to 34 mg/kg (2007 and 2008), while K decreased from year 1 to 2 (348 to 312 mg/kg) but increased in year 3 (360 kg/mg). Sulphur showed no significant change throughout the project (24, 19 and 25 kg/mg).

Nutrient budgets demonstrated that the majority of farms created a surplus of P, K and S with excessive use of imported nutrients through fertiliser. It’s apparent that not all imported/exported nutrients from the farming system are accounted for when fertiliser decisions are being made. Basic economic analyses revealed that potential on-farm savings from $29 to $636/ha could be achieved through maintaining the optimum agronomic range in soil tests.

Water use efficiency data demonstrated that participating farmers generally reached or exceeded the industry average WUI of 1t DM/ML, averaging 1.35, 1.42 and 1.27t DM/ML for irrigation seasons 2006/07, 2007/08 and 2008/09 respectively.

The project delivered nutrient budgeting information, irrigation efficiency information and information to assist with better fertiliser management on farms.