HAURAKI PLAINS SOIL.

Hauraki Plains Gazette, Volume XXXIV, Issue 4538, 12 March 1923, Page 1

HAURAKI PLAINS SOIL.

QUESTION OF MANURING. NAURU PHOSPHATE ADVOCATED. At the conclusion of the address on Hauraki . Plains soils, given at Ngatea on Friday last (and published in Friday’s issue) Mr Heighway referred to some published remarks by Mr T. H. Patterson, of the Department of Agriculture. Hi these Mr Patterson had given general advice upon fertilisers, which could perhaps be amplified to meet the special needs of the Hauraki Plains. Mr Patterson, in his remarks, as reported, seemed inclined to recommend the use cf superphosphate largely for the Plains soils. Mr Heighway said he believed that where nature had provided cer* tain conditions, those conditions should be used .to advantage instead of employing more costly artificial methods of achieving the same endChi the Plains they had a superabundance of humus and ample moisture, and these conditions assured plenty of humic acid and carbondioxide to make available the plantfood content of Nauru phosphate. Supherphote was simply half Nauru phosphate and half sulphuric acid, the acid being used to increase the solubility of Nauru phosphate. This mixture had the effect of reducing by half the amount of phosphate in a ton of manure, and therefore doublling the unit cost of that manure, although at the same time the acid did give an extra service in speed. Under some conditions, however, that speed was not essential. Mr Patterson had said that Nauru phosphate was not solluble in water, but this was hardly a fair presentation of the case, because nobody wanted it t,o be soluble in pure water. The soil moisture that it did encounter was not pure,, but carried acids which had the same effect in progressive stages as the application of sulphuric acid had artificially, and it was surely a more common-sense and practical procedure to)let nature do hetwork for nothing rajther than pay a fertiliser merchant for a process that for these conditions was largely unnecessary.

The application of superphosphate pure on Hauraki Plains soils in the autumn, as recommended by Mr Patterson, might hardly be the best practice in view of the local conditions obtaining in winter when the excess of moisture oh low-lying lands would precipitate a loss of available fertility. Practical experience in the upshot was the besjt guide, and actual experience pn the Aka Aka. swamp, on the Hauraki Plains soils near Puriri, no the peat areas near Gordo.'iton, on swamp lands at Ohinewai, and on certain swamp areas in the Bay of Plenty showed that raw rock phosphate'was the cheapest and most endurable main fertiliser to use for those conditions.

Mr Heighway said he also joined issue with Mr Patterson in his recommendation that Belgian slag, at the same price, was preferable to finelyground Nauru phosphate for Plains conditions. The phosphate gave twice as much plant-food value, and on the heavy and rich soils of the Plains the rate of availability would approximate in practice while the superior plant-food content of the phosphate would secure more. lasting effects. The experience gained by Home authorities , and the definite recommendations of world experts, backed up by practical experience already gained in New I Zealand,, suggested that the advice given by Mr Patterson might' be modified with advantage. Raw rock phosphate by itself, and combinations of it with superphosphate in proportions found desirable, would give the farmers betjter value under practically all conditions than imported foreign fertilisers, such as Belgian slag. As a matter of fact, New Zealand farmeijs, were being misled to some extent by trade propaganda, and a slightly unfair use was being made of incomplete and belated tests carried out by the Department of Agriculture at Tte Kuiti. These were laid down at an unseasonable time, which imposed an undue handicap on one Farmers needed to watch carefully that their future interests were not jeopardised. They would find it very much to their permanent, advantage to follow the, advice given by Mr A'. F. Ellis, Phosphate Commissioner, for New Zealand, to wherever possible give preference to fertilisers based upon Nauru phosphate in which the New Zealand Government was 'so largely interested, rather than continuing patronage of inferior imported phosphates. The leading authority on the practical use of fertilisers in the Dominion to-day was undoubtedly Mr J. A. Pond, F.C.S. '{late Government analyst), and his recommendations were for an increasing use of Nauru phosphate as the base of fertilisers, with where speed was necessary, a proportion of superphosphate, in the case of the Hauraki Plains the proportion of superphosphate required, particularly on grass lands, was very small because of the suitable, conditions provided by nature for the successful use of a highly concentrated, sweet, and non-aeid fertiliser, such as finely ground Nauru phosphate. JThe guiding principle was simply to discover the conditions most suitable- for the best use of superphosphate and raw phosphate and where necessary combine the two in proper proportions.