The pasture grown on your farm is the cheapest source of animal feed available to you.

Production costs inexorably increase yearly. Despite apparently high dairy returns, high on farm inflation means dairy farmers will be focusing hard on minimising environmental impact and maximising returns from farm inputs, with fertiliser being no exception.

The temptation may be to reduce, or forgo, fertiliser to assist with balancing the books. In this case, it is very important that you gather the required specialist information from people you trust to help formulate your fertiliser policy and understand what the positive or negative consequences of whatever decision you take will be.

Because fertiliser does represent a large input cost, it deserves some time, effort and mental focus to nut out exactly what your response to the current cost: benefit relationship for your farm fertiliser policy will be.

Pasture growth deficits are greater when soil fertility is sub-optimal because wet, cold and dry soil conditions all restrict the ability of soil biological and chemical processes to keep nutrients cycling in soils and plants growing in them to acquire these nutrients.

If belt tightening is required on your farm, consider these actions to get the best from your fertiliser spend

Soil and herbage (when pasture is growing well) tests will help identify soil fertility issues for both for major and trace elements:

• Dairy: consider whole farm testing (every paddock) to determine areas requiring capital, maintenance and sub-maintenance rates of lime and/or fertiliser nutrients.
• Mixed livestock: consider dividing the farm up into land management units (LMUs) based on factors like slope, aspect and topography, which affect potential production, and soil test these LMUs separately to develop a differential fertiliser and lime application plan to maximise the return from your spend.

Identify areas that you intend to plant either winter or summer forage crops early enough. This is so that soil testing and corrective lime and fertiliser application can be carried out prior to planting. Then ensure the right type and amount of nutrients are applied at planting (and side-dressing if necessary) to maximise yields. Growing crops is an expensive business if you get poor yields!

Use nitrogen fertiliser tactically to fill predicted feed gaps when climatic conditions for use allow i.e. adequate temperature, moisture but not in conditions that will promote direct leaching of applied N fertiliser. Gibberellic acid together with liquid N (half rate compared to granular application) on the shoulders of the season (i.e., first application in late winter/early spring and last application in autumn) can help reduce total N fertiliser applied for the season.

Lime is not a substitute for fertiliser nutrients that are limiting. Above pH 5, pasture responses to lime are generally lower than to P, K, S if these are limiting. Ideally, both nutrients and lime should be applied as required to optimise pasture production and quality.