Soil Quality

The green manure calculator provides a comparison of relative benefits between a green manure phase and a grain crop within a defined rotational sequence. Results provide an indication of economic costs and benefits based on variable inputs.

The wheat yield potential calculator provides an estimate of rainfall limited grain yield. This has been based on a modified version of the French and Schultz (1984) calculation. In this case available water is the equivalent of 30% rainfall received between January and March plus 100% of rainfall received between April and October, with losses estimated at 30% of April - October rainfall. It is assumed that every millimetre of available water will produce 20 kg of wheat per hectare.

A more comprehensive online production model designed to provide grain growers with real-time information about the crop during growth can be found at the Yield Prophet website

French, R.J. and Schultz, J.E. 1984. Water use efficiency of wheat in a Mediterranean-type environment. I. The relationship between yield, water use and climate. Australian Journal of Agricultural Research 35, 743-764.

The lime cost calculator allows you to compare the total cost (lime, freight and spreading) per hectare for the equivalent of 100% neutralising value (NV) of lime. Using published values* it discounts the NV to account for the reduced effect of larger particle sizes which reduce the short term capacity of the lime to change the soil pH.

*Neutralising value and relative efficiencies of particle sizes in changing soil pH of 100, 50 and 20% for limes less than 0.5 mm, 0.5 - 1.0 mm and greater than 1.0 mm are from Cregan, P.D., Hirth, J.R. and Conyers, M.K. (1989) Amelioration of Soil Acidity by Liming and Other Amendments. In "Soil Acidity and Plant Growth" (A.D. Robson, ed.), pp. 205-264. Academic Press.