39

(iii) Top-dressing The carrying-capacity of the land has been increased markedly by the greater use of fertilizer. The outstanding feature is the dominating importance of phosphatic fertilizers :

(Thousands of tons)

Normally, New Zealand supplies of rock phosphate for superphosphatemanufacture come from Nauru and Ocean Islands, and production and distribution to fertilizer-works were administered by the British Phosphate Commissioners, an organization set up following World War I to distribute the phosphates from these mandated islands. Provision was made for Great Britain and Australia each to obtain 42 per cent, and New Zealand 16 per cent, of the total output. Great Britain, however, obtained her supplies from other sources, and Australia and New Zealand have shared the output from Nauru and Ocean Islands. After the phosphate rock reaches New Zealand it goes to the fertilizerworks ; eight works manufacture superphosphate and one manufactures a heat-treated phosphate. The potential output of all works combined is in the vicinity of 700,000 tons annually. Blood and bone and blood and bone-dust are by-products of the Dominion's meat industry, and they are used largely for market gardening and in mixtures for annual crops. Potassic and nitrogenous fertilizers are used to a limited extent only ; potassic fertilizers are used for top-dressing pastures in certain areas when the soil is deficient in potash and for special mixtures for annual crops. Nitrogenous fertilizers are used mainly by marketgardeners and orchardists. The areas top-dressed were ag follows :

(Thousands of acres)

Season. Superphosphate (Straight). Other Phosphates. Blood and Bone, Blood, Bone, <fec. Potash, Sulphate of Ammonia, Nitrate of Soda. Total. 1928-29 275 151 25 14 465 1932-33 307 59 26 11 403 1937-38 447 121 22 21 611 1942-43 295 27 35 5 362 1945-46 445 27 24 11 507

Year Ended 31st January, Artificial Fertilizer Only. 1 Lime Only. | Fertilizer and Lime. Total Area Top-dressed. 1927 1,410 107 4 1,521 1932 2,068 387 * 2,454 1937 2,122 177 1,027 3,326 1942 2,324 380 1,508 4,212 1948 2,654 548 1,481 4,684 * Not quoted for this year.