Establishment of pasture on yellow‐brown loams near te anau

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Abstract
Five forms of phosphate† Formerly manufactured by Permanente Metals Corporation, U.S.A. The process, developed by T.v.A. in America, consists of fusing a magnesium silicate such as olivine or serpentine with phosphate rock in an electric-arc furnace and rapidly cooling the melt in high-pressure streams of water View all notes—superphosphate, lime-reverted superphosphate, serpentine superphosphate, basic slag, and fused calcium magnesium phosphate (Thermophos†);were evaluated on Te Anau yellowbrown loam. Thermophos, despite its lower phosphorus content, proved greatly superior to superphosphate when both were applied at 6 cwt per acre. Lime-reverted and serpentine superphosphate were inferior to superphosphate, but basic slag appeared slightly superior on an equivalent phosphorus basis. In further trials which included rates of superphosphate and Thermophos from 3 to 15 cwt/ac in the presence and absence of 2 tons lime, Thermophos again proved superior to superphosphate, especially in the absence of lime. In the superphosphate treatments lime either had little effect or aided response, but in the presence of Thermophos it generally depressed growth. A high percentage of the phosphorus in Thermophos was recovered in the surface AI-P and Fe-P fractions, but the Ca-P fraction was higher in superphosphate. Addition of lime to Thermophos increased the Ca-P fraction. The magnesium and trace elements in Thermophos were not considered to have been responsible for its superiority. The importance of silicon is not clear.