Phosphorus Budgeting Tool

For many farming enterprises, the application of phosphorus fertiliser is one of the largest annual expenses. Holbrook Landcare Network, as part of the ‘Carbon Farming and Your Business’ project, has developed a phosphorus budgeting tool which can be used in conjunction with soil testing. An annual fertiliser plan and budget can be developed by using this easy to use, excel-based tool. Access the tool here

For many farming enterprises in the high rainfall zone, the application of phophorus is one the largest annual expenses.

The old rule of thumb of one kilogram of phosphorus per dry sheep equivalent (dse) has been greatly refined through research to improve profitability and minimise environmental impacts.

The Phosphorus Budgeting Tool enables farmers to calculate the rate of phosphorus required for their property based on stocking rates, current phosphorus levels and production goals. An annual fertiliser plan and budget can be developed using this tool.

This tool will help farmers to get the most out of their soil test results and design efficient fertiliser programs.

Why use the Phosphorus Budgeting Tool?

The Phosphorus Budgeting Tool can be used in a number of ways:

  • To create an annual fertiliser programme

  • To inform the annual farm budgeting process

  • To best allocate fertiliser given a pre-determined budgeted amount

  • To maximise fertiliser efficiency

How the Budgeting Tool will help you:

The Phosphorus Budgeting Tool will:

  • Calculate the total Phosphorus requirements for each paddock (maintenance + capital)

  • Allow you to compare the cost of using different fertiliser products

  • Help you to prioritise which paddock to fertilise and what rates to use

  • Help you to create a list of products and quantities required to assist with ordering, as well as an indicative budget based on current fertiliser prices

What you need to complete the Budgeting Tool:

This tool is designed to create an annual fertiliser plan and budget for improved pastures. To complete the Phosphorus Budgeting Tool, the following information is required:

  1. Paddock size (ha)

  2. Stocking rate (dse/ha). This can be per paddock or farm average. 

  3. Current soil test results

  4. Current fertiliser product information including: price, phosphorus % and spreading cost

Note: Regular soil testing should be carried out to monitor change over time. The recommendations in this tool are designed to supply an adequate amount of phosphorus fertiliser for improved pastures. It assumes other major nutrients and pH are within optimum range. This is to get the full benefit of the applied phosphorus.

Tailoring your Fertiliser Budget

Fertiliser Rate

The tool will calculate ‘Total’ requirement (kg P/ha) (M Only or M+C).

The ‘Budget Rate’ (kg fert /ha) is the exact rate of fertiliser to achieve the targets based on the product you have selected.

The ‘Spread Rate’ is the ‘Budget Rate’ rounded to the nearest 25 kg/ha increment to make it simpler for fertiliser spreaders when applying the products.

Change the fertiliser product to compare the cost of different products.


The tool will calculate ‘Total’ tonnes required for each paddock by multiplying out the Ha. It will also add up the total tonnes of each product required to assist with ordering product.

The tool will calculate a total cost per paddock and an overall budget figure based on the products selected and using the fertiliser prices that you have entered into the Fertiliser Products table.

Change the fertiliser product and/or the toggle buttons to tailor the overall budget.

Disclaimer: The information contained in this product is based on broad assumptions; it should only be used as a guide and may not apply to your situation. Holbrook Landcare Network provides no warranty about the accuracy of the content enclosed. Holbrook Landcare Network shall not be liable for any loss of profit or any other commercial damages resulting from use of this product. There is a need for land holders to conduct on-going soil testing on their properties to ground-truth their fertiliser application decisions.

The ‘Carbon Farming and Your Business’ program is supported by funding from the Australian Government. The development of this tool was also supported by: