As part of MINAS farmers have to declare their intended use of nitrogen and phosphorus based on soil test results. MINAS has stimulated farmers to better understand the efficiencies of their farm systems. This has led to a reduction in nitrogen fertilisers use, and better management of animal manure.

Farming south east of S.A. compared to Elleker W.A. The main difference is soil types - black loam, chocolate loam and sand over clay in South Australia with a pH of 5.5 to 6.5 in water while here soils are sand over clay with a pH of 4.5 to 5 in water.

In South Australia perennials, such as rye, cocksfoot, phalaris and tall fescue, were easy to establish. Sowing was in a fine seedbed with 2.5 tonnes of lime to the hectare (worked into the soil) and 125 kg of superphosphate to the hectare. This grew in a 28inch rainfall, April to November, with a bit falling over summer. Not much different to the Albany area. We farmed 725 acres with 100 acres irrigated and sown to perennial rye and white clover with a small area of lucerne. We ran dairy cattle, beef cattle and sheep.

Dairy areas received 150 kg of super potash per hectare in autumn and 4 tonne of urea in May/June with 125 kg super potash and nitrogen in September, then the same every eight weeks until March.

I attended a discussion group monthly; this also involved a farm advisor we employed who kept us up to date on new farming methods. At the end of each year we would benchmark ourselves against other members of the group, that is, how much grass we grew, how much we used and how much we wasted.

In Elleker, we are trying to come to terms with kikuyu as a perennial grass, as this would be sprayed out as a weed in South Australia! I have tried to establish other perennials, but so far have only succeeded with perennial rye. I have tried fescue and phalaris with little success. I think the pH is too low. I have used 2.5 tonne of lime per hectare, but as local lime is only 70% neutralising value I may have to apply

Farm gate balances are a useful way to calculate the difference between inputs into a farm such as fertilizer, feed and manures and what goes out as products or outputs. A case study of farm gate phosphorus (P) budgets and management practices across Torbay grazing properties was undertaken earlier this year to evaluate the effectiveness of nutrient management. Twenty one farmers were interviewed to obtain first hand information on their farms. Information gathered during the February 2004 soil testing subsidy program offered by the Departments of Environment and Agriculture was also incorporated. The P retention capacity in the rooting depth of four soil types common in Torbay was calculated.

The P use efficiency and surplus of Torbay grazing properties is summarised in graph 1. P use efficiency is expressed as an input:output ratio, the units of P applied to each property for every unit of P taken off the property in commodities.

The input:output ratio is an indicator of farm nutrient use efficiency, with lower ratios indicating more efficient use.

This case study also shows that low P retention soils (ie PRI<2) are common throughout Torbay, and over fertilising is a frequent occurrence. Over fertilising is money down the drain. Soil P status can be determined from regular soil testing. The consequences of spreading large amounts of superphosphate in a single application vary across soil types. Sandy soils are prone to excessive leaching while heavy soils with poor infiltration are prone to surface erosion. Any management that can enhance plant P uptake, such as the establishment of perennials, or increase soil P retention, will be of great benefit to the farmer. Soil improvements like spreading clay on sandy soils will increase the nutrient retention capacity, reduce over fertilising and improve the efficiency of P use.

Regular soil testing is needed to guide fertiliser decisions, for improved soil health and pasture productivity. Balancing nutrient inputs with outputs is one way to check levels of fertiliser loss, leading to environmental and economic benefits for the farm and catchment.
Stephen Lance CENRM

Graph 1. The average input:output ratio was 3.7:1 which is better than grazing farms in the Peel Harvey. However, a large number of Torbay farms have very high input:output ratios, greater than 5:1.