Grains and field crops
Residual value of phosphate fertilizers.
Location: South Carrabin Block of Merredin Research Station.
4th successive crop on new land. Trial has shown that the effectiveness of the different types of rock phosphate were about the fifth to one tenth as effective as the fresh (triple) superphosphate applied in 1984. The effectiveness of the superphosphate, decreased by 60 between year 1 and 2, and by a further 10-15% by 1987. This experiment will continue as pasture for 1988 and 1989, and will be re-cropped in 1990. The experiment is also assessing soil testing for P. but soil test data as yet incomplete.
Residual value of superphosphate for lupins, barley and wheat.
Location: Badgingarra Research Station
In the experiment, 6 levels of superphosphate were applied to a previously untreated plots once only, in May 1985, 1986 or 1987. The residual value of this P was measured in 1987, using lupins, barley and wheat, relative to the P applied in 1987.
Residual value of superphosphate for lupin:oat:wheat rotation.
Each year, 6 rates of superphosphate are applied once only to previously untreated plots, in 1985, 1986, 1987, 1988 or 1989. Lupins are sown on the plots in the year the P is applied, oats are sown in the second year, followed by wheat in the third year, lupins in the fourth year, oats the fifth year etc. The aim is to measure the residual value of superphosphate for the lupin:oats:wheat system recommended for these soils.
Effectiveness of granular and finely ground reactive apatite rock phosphate compared with superphosphate.
Location: Badgingarra Research Station.
Four levels of each fertilizer (superphosphate, granular North Carolina rock phosphate (NCRP), and the same sample of granular NCRP ground to give medium and finely ground NCR?) were applied to the soil surface in mid May 1985 and incorporated into the top 10 cm of soil when the plots were sown in late May with Chittick lupins in 1985, Mortlock oats in 1986 and Jacup wheat in 1987. In 1986 and 1987, four levels of superphosphate were applied once only in each year to plots that were not treated with P fertilizer in previous years, so that the effectiveness of the 1985 fertilizer dressings could be calculated relative to fresh superphosphate applied in 1986 and 1987.
Residual value of superphosphate.
Location: North Cunderdin.
Levels of superphosphate applied once only in May 1986. The residual value of superphosphate measured using Medicago polymorpha cv. Serena or Trifolium subterraneum cvv. Dalkeith and Northam (50/50 mixture by seed weight).
Number of Pages
Bolland, M D, Baker, M, Phillips, C H, and Proudmore, D. (1987), Residual value of phosphate fertilizers.. Department of Agriculture and Food, Western Australia, Perth. Report.