Two years ago we put out 125 kg/ha Mo superphosphate mixed with 10 kg/ha of Mount Barker subclover. The paddock was shut up for 12 months. The clover grew to 200-250mm high, was allowed to seed and die back in the summer.
This resulted in forming some humus and top soil, and last year the grasses grew tall, mainly microlaena, and was grazed through winter at 6 dse/ha.
There is some trend against using super, but apart from putting tons of poultry shed litter on the paddock, you can't get growth, thus, no organic matter and no microbes.The microbes and fungi act as a digestive system for the plants, making the locked up nutrients available for the plant's growth.