HAURAKI PLAINS SOIL.

Hauraki Plains Gazette, Volume XXXIV, Issue 4537, 9 March 1923, Page 1

HAURAKI PLAINS SOIL.

DETAILED ANALYSIS. REPORT BY MR.. E'. W. HUGHES. The following full report concerning an analysis of the Hauraki Plains soils was prepared by Mr E. W. Hughes, B.Sc., chemist of the New Zealand Co pperaitive Dairy Co., Ltd., and is to be delivered to-day to the Ngatea branch of the company:— At our last quarterly conference of committees of the N.Z. Co-operative Dairy Co., Ltd., the subject of soil fertility was mentioned in connection with- stock diseases, it being' thought that possibly there might be some connection between the constitution of the soil of this district, and certain effects noticed in the stock after having been kept for some time in some localities. Arising out of the discussion on that occasion five samples were taken and analysed, and I porpose ;tp submit, these to you to-day with certain explanations and practical comments. T|ic analysis of soil is chiefly valuable in connection with types of soils —that is, as indicating the essential differences of swampy soils, ' sandy soils, pumice soils, loamy soils, clay soils, and volcanic soils, and so on. It can best, be used in a big way to guide broad conclusions rather than in an intensive way to define just how much of this manure or that a man| might use on a particular paddock. The chemist can help us a lot, but he cannot, in our present state of knowledge, replace practical /farming experience. However, it must always be remembered i,..at the soil and changing weather conditions make a. laboratory of the soil itself, so that the conditions analysed to-day are changed in slight degree to-morrow. In nine cases out of ten a detailed soil analysis is not of much practical use to ft farmer, and usually does not pay for the trouble involved. There are t,wo ways of analysing a soil: (1) A full detailed analysis of every ingredient in it, showing the percentage, of both available and unavailable constituents; (2) a state ment of the main ingredients only, and their percentage, but not; mentioning their availability. The most complete method takes time, and is costly, but even a brief analysis of the second classes fairly costly, too. The most valuable method is’ that showing the amount of available plant, food, because pl ant "food is not of much use unless it is available, and that is the method we have tp-ken in your case. You will, however .note that this

analysis leaves unrevealed the amount of at present unavailable nutriment—an amount which may be large, and which constitutes a bank or reserve which may gradually ne drawn on through cultivation and the operaton of natural forces. The samples of soils taken were as follows, their prior treatment being given as fai' as possible :— No. 1. This sample was taken from Mr Clare’s paddock and consisted of black, loose soil. The paddock had been ploughed twice and one crop of maize taken from it. It is believed to have been limed. No. 2. This sample was taken from the back paddock of Mr Clare’s property, and consisted of black, loose soil, but not so loose as sample No. L It had been harrowed and sown down. No. 3 This sample was taken from Mr Coppin’e farm, and consisted of brown, loose soil, similar in texture to No. 1 and No. .2. Rs treatment had been to be harrowed and sown down. No. 4. This sample was taken from Mr Banks’ property, and consisted of dark brown loose soil, it. also had been harrowed and. sown down without further treatment. Nb. 5. This was from Mr McDuff’s farm, and consisted of light brown soil with a fair amount of clay material mixed with the loose material. It also had been harrowed and sown down. The detailed analysis of these samples is as follows, tests as co available contents —not total contents No. 1. Lime, .068 per cent.; phosphoric acid, .02 ; Potash, .033 ; nitrogen. .146. No. 2. Lime, .052 per cent.; phosphoric acid, .02 ; potash, .012 ; nitrogen, .1. No. 3. Lime, .056 per cent.; phosphoric acid, .022 ; potash:, .016 ; nitrogen, .13. No. 4. Lime, .074 per cent.; phosphoric acid, .015 ; potashj, .016 ; nitrogen, .12. No. 5. Lime, .14 per cent.; phosphoric acid, .021 ; potash, ( .023 ; nitrogen, .13. The average of the five tests is : Lime .078 per cent.; phosphoric acid, .019 ; potash, .02 ; nitjrogen, .125,

The standard fertile, soil percentage is : Lime, .30 ; phosphoric acid,, .08 ; potash, .03 ; nitrogen, .02. Now, this table, without some explanation, will probably be simply so much Greek, The best way you can make use of it is to compare the average of the five samples with, the constituents of an ordinary standard fertile soil, as fixed by definite authorities. This is done in the last two columns, but a better comparison may be used to ascertain the real significance of the analysis made, and that is to translate the percentages into the actua] pounds weight of: the different elements, of fertility. On the average the topi six inches of soil over an acre weigh 2,000,0001 b, so that if we multiply these fractional percentages by the weight of an acre we get this practical and useful table. Comparison of available fertility in pounds:—

Comparing these figures we see that the position in connection with each of the main elements of fertility is as follows :— Lime.--The average content is onequarter that of the standard fertile soil. Phosphoric Acid. —The average content is less than one-quarter that of a standard fertile soil. Potash —The average content is two-thirds that of a standard fertile soil. ;■ Nitrogen.—The average content is 614 times that of a standard fertile soil. ! An important point to be noticed here is the unusual and unnatural balance between the mineral matter and nitrogenous compound cf the soil. With lime find phosphate being less than a quarter of an ordinary standard fertile soil and nitrogen* being six times greater, this shows that, where in an ordinary soil there is a certain ratio between the lime and phosphate content and the nitrpgen content, in your case this ratio is increased to 24 times that of an ordinary fertile soil, because your lime and phosphate is less than a quarter of the average and your nitrogen is six times greater than the average. These detailed analyses show just what we expected to find from a general knowledge of the history of the district and former investigations. Earlier analyses by the Uepartmerit of Agriculture showed the same three facts that stand out here: 1. The excess of nitrogen, due to abundant humus. 2. The deficiency of phosphoric acid and potash and other'mineral matter. 3. An acid soil due tp a deficiency of lime. These three things are characteristis of swamp areas of the Auckland province. The Rangitaiki Swanjp, in the Bay of Plenty, is very similar in composition to your own soils, but on. the whole is slightly richer in mineral matter than are yours, and less excessively supplied with nitrogen. These broad conclusions bear out my earlier remark that an individual analysis, paddock by paddock, is not, worth while, for although we here , analysed several distinct district types of soil, no outstanding chemical difference is detectable, and on broad lines the treatment suitable for one is suitable for all. T make this *’emark to discredit any desire on the part of individual farmers to have each paddock analysed with the idea that they can dsicover a particular manure to suit each one. This is quite a fallacy.

' Now, having discovered the main characteristics of the Plains soils, the next thing to do is to ask whether it is reasonable t.o suppose that these characteristics so revealed have any bearing upon the stock troubles you have been experiencing. Such a suggestion seems to be at least feasible, and it is likely that this is the main factor in your difficulty. There may be, and propably are, other factors bearing upon it of a veterinary nature, but into this I am unable fo goIf the argument so far appears to you as being reasonable the next thing to inquire is whether there are any practical ways of endeavouring to improve the soil balance between minerals and nitrogen, and so supply more balanced nourishment to the stock. When speaking here in October I stressed the importance of lime and mineral matter in the welfare of young: stock and the production oi milk, and it is necessary to just briefly mention the same points again. Taking milk first, a complete chemi-

cal analysis of this simple-looking fluid reveals the presence of no fewer than 44 different constituents. The •7 per cent, of ash divides again into 16' different mineral compounds, the names of which are so fearsome and tongue-tangling that we wont trouble to mention them. The principal items are compounds of phosphate and lime, with traces of potash, so that it is easy to emphasise these two points : (1) That t,he presence of these minerals in amply available amounts is essential to the best healthy productivity of milking cattle ; (2) <that continued dairying on any land is' inflicting a steady withdrawal of thes-c ( elements to the detriment ofl that land. 1 The maternal instinct of a cow is so strong in connection with maintauhing her milk flow that if she cannot get sufficient mineral matter from the food she eats to make milk she is capable of drawing upon her own frame for the necsesary elements. Careful tests in food experiments have definitely proved this. fact, surprising as it may seem. It, therefore, simply boils down to this : you cannot make something out of nothing, and if the cow cannot get the elements for the manufacture of milk from her food, she will either get them from her own frame or, after going as far as can on that line, quit the job. Allowing for the necessity of her building a strong calf, maintaining her milk flow, and keeping her own bodily strength up to the mark, it is porbably safe to say that each cow requires the equivalent of lewt of available phosphate yearlv.

Your actual problem 1 ore. would seem to be affected by three things : (1) Bad or poor water. (2) Deficient drainage. (3) A comparative lack of mineral matter in the soil. The provision of a good water'supply is a problem to be faced by each man individually. The necessity for it is obvious, as no animal can thrive upon a full diet of bacteria. The sweetening effect of good drainage is undoubted, but your district is new yet, and the land has tp settle and consolidate before this can he applied as etxensively as you probably know it should be. • Thi? loaves the third point to be tow ned upon—the comparative lack of mineral matter in the soil—and it is upon this aspect that j feel obliged to throw out some suggestions that may be of value. The main point upon which I wish you to fix your attention here is this : Quality of feed rather than bulk of feed. It is not so much the purpose of a fertiliser to make grass grow, but to make good grass grow. There is no trouble cbout grass growing with you—the whole point is the quality of nutriment conveyed in that grass. The application of fertilisers to your soils would perhaps not, be detectable by the eye in any increased capacity for growth, but I think there yvould be no question that the stock would find the place where a fertiliser was applied with the increased palatability of the grass growing there. For the purpose of comparison we might make this little analogy: That the excessive nitrogen you have is a stimulant much as whisky is, and that the phosphates and lime and potash take the place of beef steak and rolled oats in the human economy. Some people find whisky a very nice liet, but for endurance there is no doubt beef steak and rolled oats take the palm. Phosphoric acid, that, is so essential in your soil, is available for application in three common forms. (1) Superphoshpate. (2) Basic slag. (3) Ground Nauru phosphate. And of these there is no question but, that for your conditions and circumstances the lastmentioned is the cheapest and

most economical proposition. You have ideal conditions for its effective use—a soil full of humus, a soil of an acid nature, and plenty of moisture to facilitate the availability of the phosphate. Pure Nauru phosh; to contains 84 per cent, tricalcie phosphate, superphosphate 44 to 4G per cent., and basic clag about 40 per cent. Superphosphate is simply half Nauru phosphate and half suplphuric acid mixed together so that, the acid will make the phosphoric content of the Nauru phosphate more immediately soluble. On dry soils, deficient in moisture it is certainly wise to use a good deal of superphosphate, say, half and half, but for the Hauraki Plains conditions there is no question at all, but that the use of superphosphate for application to grass lards would be uneconomical and wasteful. Basic slag is a good phosphatic manure, and can be used profitably provided the best grade is secured, but with the finely-ground Nauru phosphate now Available as imported by the NewZealand Government, and giving nearly twice as much plant food for less money, there is no donut that in practice it will give equal and more lasting results than imported basicslag. A good deal of misapprenension ex - ists as to the'value of this manure, ano this misapprehension to a large extent is being fostered by interested fertiliser merchants. lhe plain truth is that ground phosphate, such as Nauru, has been in use in New Zealand successfully for the last 30 or 40 years as the basis for compound and mixed manures, but with the superior grinding to which it has now been subjected, it can, where suitable conditions exist, be advantageously applied in its pure form. -A great deal of experimental work has been done in late years in discovering the extent to which raw phosphate may be used„ and the weight c, .evidence is strongly swinging in favour of a. more extensive use of this .cheapest source’ of phosphoric supply. One of the best authorities, Dr. G. S. Robertson, wrote as follows to Mr A.. F. Ellis (Phosphate Commissioner for New Zealand) : — “Our experience with rock phosphate agrees in general with the remarks which you make. I find that on sour soil well supplied with organic matter, and where the -rainfall is rather high, say, about 30in, there is little to choose from between the various rock phosphates, and that they are all as efficient, as the best types of basic slag. . . . Where the soil is deficient in lime !■ am certainly of opinion that these rock phosphates will give more satisfactory results than superphosphates.”

His opinion exactly fits the- conditions of the Hauraki Plains, and while numerous other authoriities might be quoted, it is not necessaiv to do so, as. we have our actual experience in the Auckland province to go on. Nauru phosphate has been used already in the Puriri district very successfully, and cases have now been secured from other localities ps well. LIME. We now come to the question lime. While lime’is certainly an essential element of fertility for its own sake, it rias an additional, effect in releasing mineral matter otherwise locked up in the soil. It is known technically as a releaser of fertility, and to that extent it adds nothing to the mineral richness of soils, but merely makes available what is already there. Lime is procurable for the'Hauraki,Plains from three sources. The first source is on the Plains itself in the deposits of shell lime near Miranda. A proposition to float a company to work this has been under discussion, but is at present in When the estimates were taken out it, was considered that lime could be made available at about £1 per ton, and, provided tfcis could be done, it would certainly be a big asset to the district.

, Pending development of that source of -supply, lime is, available from the King Country and Whangarei. I have made inquiriel and find that a scowload of from 80 to 130 tons of lime could be supplied at Ngatea or Paeroa at approximately £2 2s a ton, bago in. King Country lime can be landed at Paeroa for about 27s a ton, net, bags in. or 6s a ton less if fanners supply bags. Farmers will need to take into consideration cartage facilities, to determine which source of supply would be the best. The best, results from a practical point of view would be secured by not applying lime and phosphate together to the same piece of land, but at intervals of probably two years. Where farmers have heavy freight and long cartage it would pay them to spend their money on actual manure with its concentrated plant food rather than on lime, and after an interval of two years follow on the same piece of land with lime in order to finally release what fertiliser might not have become available. Farmers better situaJted as regards cartage might apply both, separately, and on different pieces of land, and after, two years reverse the dressings. In the case of a first dressing of phosphate, it would probably be'best to apply about sewt to the acre, and in order to carry out the dressings in an experimental way, farmers can satisfy themselves by running strips down 'the centre of the pad dock and discovering whether the cattle grazed more on the top-dressed strips than on the rest of the paddock. Single top-dressing would not effect any wonderful improvement, but it would be a step in the right direction, and the wisest policy to pursue would be to steadily and consistently, j’ear in and year out, endeavour to build up an extra phosphoric supply in the soil by steady dressings as conditions permitted. Successional dressings of small amounts would be more profitable than big dressings, and.as time went on farmers would satisfy themselves from their practical expci ience as to the best practical way cf applying phosphate in conjunction with the lime. There was no doubt at all that such a policy would have to come in order to hasten t.bo establishment of a better balance between

the mineral content of the soil and the present excess of nitrogen. Year by year also the ■ excess of nitrogen would tend to work out, and, as time went on, conditions would speedily right themselves and improve. One point farmers of the Hauraki Plains would be wise to be guided on, and that would be not to buy nitrogenous manures. Bone-dust was a very popular manure containing bol’-h phosphate and nitrogen. The nitrogen content of a ton of bone-dust tv as roughly worth about. £3, and to that extent that money need not be spent. It would be far better to concentrate theii\ purchases upon purely phosphatic manures, with their higher content of the necessary element phosphate.

Some of the points raised here may seem elementary tp you, but I have endeavoured to make these remarks simple and straightforward. Many people are inclined to make,a great, mystery about fertilisers, but it is really a comparatively simple subject, and every farmer should be familiar with the main principles. There are innumerable points connected with fertilisers that time has not permitted to be touched upon because they do not directly affect your district, but I have simply given you those points that I think directly apply, and suggested that course which I know from experience will be most, applicable to your needs.

Hauraki Standard. Lime 1560 6000 Phosphoric acid 380 1600 Potash ■400 600 Nitrogen 250'0 400'