MANURES AND MANURING

Hauraki Plains Gazette, Volume XXXVII, Issue 5020, 30 August 1926, Page 4

MANURES AND MANURING

lIAURAKI PLAINS SOILS. AN INTERESTING ADDRESS. At the annual meeting of shareholders of the Hauraki Plains Coo'perative Dairy Co., Ltd., at Tui'ua on Wednesday last ah. interesting address, on “Manures and Manuring” was given by Mr Mitchell, manager of Wright Stephenson, Ltd., Auckland. Mr Mitchell said that the use of fertilisers was increasing rapidly, and the two. countries that were making the greatest use of fertilisers were West Australia and New Zealand. The speaker explained the administration of Ngaru Island, from which New Zealand, secured 150,000 tons of rock phosphate annually. No profit was made, but there was an excess of revenue over the cost of production, and this money was utilised to better the loading facilities. At present up to 2000 tons could be loaded daily. Last season severe storms were experienced and. much damage was done to the loading plant, otherwise the cost might have been reduced. New Zealand was getting 'almost: as much rock phosphate from the island as it required, and the cost could not be reduced until the facilities for cheaper working were provided. -MANUFACTURE OF SUPER.

The rock phosphate Was brought to New Zealand and ground to very fine particles. Sulphur from Texas was treated to produce sulphuric acid. Possibly some day White Island sulphur would be used, but the present produce was not of sufficient purity. The sulphuric acid and the ground pho'sphate, were mixed in equal quantities, and the “slush” Vas put aside to dry and for the chemical action to take place. When the mass was dry it was dug out by mechanic'al diggers and further treated before being bagged up ready for use. This superphosphate was the most soluble that could be got, and it produced the greatest plant growth. If something not so quick-acting was desired for autumn use basic-super should be used. This contained a ; certain 'amount of lime. USES OF FERTILISERS.

Ngaru rock was a hard mineral, and it took a long time to dissolve ii» 3 °il> except those of a peaty nature which had a high acid content. Guano was more soluble, but the phosphoric content was -much less. Bonedust was generally too costly to use. Potasr came from mines in Germany and France where there were, huge quantities. Kainit contained 15 per cent, potash and 50 per cent, cotmmon salt, and was therefore costly to use; as a potash manure.. 30 per cent potash was better value and therefore' preferable except for potatoes, which required sulphate of potash (48 per

cent, tot 50 per cent.). Sulphate pf ammonia and nitrate of soda, being nitrogenous fertilisers, were not required by Plains soils, being already too strong in nitrogen. Phosphates-, potash, and nitrogen, were the three plant foods-, a,nd if there was an excess of any one the soil had to be given the other two to balance it. Potash would stiffen up grass and make it more palatable. On the Plains top-dressing was not required to increase the quantity but to improve the quality. Stock should feed close to- the ground, and they should not do well if the feed was up to their knees, as it was on the Plains. La,nd had to be well drained to get any benefit from manuring. Lime should be used with super even up to ten cwts. per acre. To use much lesswas to waste it. The country was new and would improve with age.

In grazing pastures the greatest fault was to let the grass grow too long. If the growth got away it was desirable to run the mower over the pastures so that the cattle could feed on the short sweet grass. Let the. pastures be eaten down close, and give it a spell to grow, then feed it off again, but do not let the growth get away or all the trouble taken would be lost.

At the close of tha lecture questions were invited.

Mr Mitchell stated that it was a sheer waste of money to have samples of soil analysed, as it was- impossible to tell thereby what fertilisers were required. This could only be found by experiment.

In the discussion that followed Mr Mitchell offered, on behalf of his firm, to establish experimental plots at Turua if assured of the co-operation of the dairy company directors and the settlers.