Sulphur Investigations in North Otago

New Zealand Journal of Agriculture, Volume 89, Issue 5, 15 November 1954, Page 434

Sulphur Investigations in North Otago

By

W. R. LOBB,

Instructor in Agriculture, Department of Agriculture, Oamaru

A DESCRIPTION of research work with sulphur as a fertiliser in North Otago appeared A on page 559 in the June 1953 issue of the "Journal of Agriculture". Three trials then in progress on a certain soil type indicated that sulphur might be of some significance in promoting plant growth. One trial was on the property of Mr. W. S. Perry, Totara, and the other two were on the properties of Messrs. W. G. Spite, Alma, an B. R - Milmine, Teschemakers. These trials were laid down in July 1952 and there has been no retreatment. All have shown 'marked sulphur responses and these are still apparent. This initial success has been followed by further trials, and a summary of the position to date is given in this article. -

TN most literature on the essential 1 major and minor elements required by plants sulphur is referred to as a major element. In general it can be assumed that it is required in fairly large quantities by plants; in fact plants contain almost equal amounts of sulphur and phosphorus. It may be surprising, therefore, that sulphur has not received more attention as a fertiliser. The reasons for this may be that most soils may supply sufficient sulphur for plant growth, that sulphur is supplied in appreciable amounts from the atmosphere, espe-

daily near industrial areas, and that most fertiliser materials used have in any case provided sulphur thus maskmg any possible sulphur deficiency. The main emphasis to date has been on such nutrients as phosphorus, potassium, and nitrogen, and common fertilisers supplying these nutrients are superphosphate, sulphate of potash,, and sulphate of ammonia, all o f which contain sulphur. In trace element work many elements have a i S o been used as sulphates; for example, copper, iron, magnesium, and manganese sulphate. Such factors have hindered' the detection of soils naturally deficient in sulphur. Sulphur and various sulphates have been widely used to make soil - more acid. The use. of sulphur and sulphate Qf iron to render soils su it a ble for the g row of such shrubs as rhododendrons, azaleas, and heaths is one example of this; the use of continuous applications of sulphate of ammonia

on lawns and playing surfaces to induce acid soil conditions is another. However, the making of soils more a « d T® North Otago Stimulation of Legume Growth . The effect of sulphur “1 the pasure Blegume 8 legume growth in much the ■ same way as molybdenum 2? nnd 1 ™ lyb de num an d mtn g s Sphu r de® P how symptoms of general yellowing reduced growth S small eaves and thin stems. In molybdenum deficiency it is considered that there is no reduction in the number o nodules on the roots of legumes, whereas in sulphur deficiency the number of nodules is reduced, , , . , Total sulphur in a soil may not be a reliable guide to deficiency. In the soils of three of the trial areas the total percentage of sulphur was deter - mined as 0.042, 0.065, and 0.057, all of which would be m the range normally lr>hur from organic combination may sulphur from organic combination may De tne crlT \ , The soil tests on the areas where the best responses have been obtained are interesting and indicate high pH, calcium, phosphorus, and potash. The following table gives a comparison

between the numerical rating of normal satisfactory levels of pH, calcium, potassium, and phosphoric acid and the ratings of levels found in nine responsive trials. Phos-

Potas- phoric Normal satis- pH Calcium slum acid factory level 6.0 10 10 10 to 15 Trial 1 .. 6.7 *2O *4O 72 2 ..6.5 19 30 31 3 ..6.5 *2O 27 ' 26 4 ..6.7 *2O 16 17 5 . . 6.9 . *2O 15 24 6 . . 7.3 *2O 30 36 7 ..6.7 18.5 22 21 8 . . 7.2 *2O *4O 37 .. 9 ..7.6. *2O *4O 160

* Actual figures were greater than those shown. The possibility that sulphur deficiency may be diagnosed through plant analysis is indicated by the following comparison of percentages of sulphur in leaves of chou moellier and soft turnips taken from suspected deficient crops in the district and leaves of similar crops grown where no sulphur deficiencies are apparent.

PERCENTAGE OF SULPHUR IN DRY MATTER OF LEAVES

Suspected Apparently deficient normal per cent. per cent. Chou moellier .. 0.17 to 0.27 0.96 to 1.38 Soft turnip .. 0.18 to 0.19 0.69 to 0.99

Work on Tarry Soils Last season’s work was concerned mainly with confirming sulphur deficiencies on the tarry soils (Waiareka complex) of the districts. From results obtained these have now been confirmed, but it is by no means certain that this complex is the only type where sulphur may be of importance. One trial on an entirely different soil type has shown a response to sulphur

and also to copper sulphate. Work will therefore have to t be extended to cover other types and in this case to check on copper, as other sulphates (such as magnesium, iron, and manganese) did not give responses to the degree that copper did. The tarry soils extend over a wide area of North Otago from Tokarahi to Kakanui on the coast. Wherever these are found it is likely that sulphur may give, responses. Trials showing responses have been located in the following areas: Airedale, Weston, Alma, Totara, Teschemakers, and Kakanui.

Previously all responses to superphosphate were attributed to the phosphorus influence only. This recent work shows, however, that responses to superphosphate have sometimes been due to phosphorus, sometimes to both phosphorus and sulphur, and sometimes to sulphur only. All three of these conditions apparently occur in North Otago.

The first series of trials were designed to test sulphur and sulphates with fertilisers without sulphur and to compare superphosphate (containing sulphur) with double - superphosphate and oxalic superphosphate

(forms containing, phosphorus but no sulphur). The next series was simplified to a comparison of superphosphate, double superphosphate, sulphur, and a sulphate. In the first series all the sulphur plots, both elemental and sulphates (such as sulphates of iron, magnesium, manganese, or copper), gave responses, whereas the plots with fertilisers having no sulphur (which included beside oxalic and double superphosphate, borax and sodium molybdate) gave no responses. In the second series responses on the heavy “tar” soil were obtained from sulphur and superphosphate,

with a slight response to the sulphate used, but no response to the . double superphosphate. In this series the comparisons were superphosphate at 2cwt. per acre, double superphosphate at lcwt., sulphur at 281 b., and sodium thiosulphate at 281 b. These responses are shown in the accompanying illustrations. On the very heavy tar soil there appeared to be no response to phosphate and this is not surprising m view of the very high available phosphate tests recorded for this soil. On a soil of a lighter nature two trials, one at Kakanui and the other at Totara, indicate responses to both

sulphate and phosphate. Here responses to both superphosphate and double superphosphate were observed and sulphur also gave a good response. The response to double superphosphate in one of these trials, though observable, was not as marked as that to sulphur or superphosphate. Stock preferred the superphosphate plot, which . supplied both sulphur and phosphorus, on this trial.

Another trial in this series at Kakanui has given a very marked response to double superphosphate at lewt. per acre. Symptoms and Types of Responses Responses so far have been confined to red and white clovers, to french beans, and to rape. No attempt has been made to investigate the full range of crops that might be involved. One of the first leads to this investigation was the unnatural colour developed in certain rape crops in the district. These symptoms have often been ascribed to natural “ripening” in the rape crop. Interveinal yellowing, the development of bronze colorations often deepening to purplish and red leaf colour, should be suspected. When rape ripens normally it turns bluish or grey-green. The main symptom in clovers appears to be a general yellowing and stunting of the plant similar to the condition in molybdenum deficiency. Symptoms in turnips and chou moellier similar to those in rape have also been noted (as in the plants on which the tests referred to on page 435 were made). These no doubt would respond to sulphur treatments. The symptoms in french beans are similar to those in rape. The leaf is not malformed as in molybdenum deficiency, the yellow coloration is distinct between the veins, and the veins seem to stand out dark green by contrast. The leaf veins in molybdenum deficient plants seem also to be yellowish. Though not malformed, the leaf is very stunted. The illustration on page 436 of bean leaves and that at right of rape leaves show this.

An ■ interesting occurrence in the rape crop illustrated on page 436 was observed on the sulphur treated area. Some of the leaves on the sulphur treated area were perfectly normal on one side of the midrib and pronouncedly abnormal on the other side. The abnormality was exactly the same as that occurring . in the untreated rape plants. Rates of Application of Sulphur At the outset of these investigations no reliable information on the question of rates of application of sulphur was available to the author. Normal rates of superphosphate and approximately half rates of non- sulphur forms of. phosphate were used (that is, i n North Otago lewt. to 2cwt. per acre of superphosphate ana oxalic superphosphate and |cwt. to lewt. of double superphos-

phate). The sulphates were used at 281 b. and 561 b., the sodium thiosulphate at 1001 b., and sulphur at 281 b. and lewt. per acre. In the second series the comparisons were simplified to 2cwt. of superphosphate, lewt. of double superphosphate, 281 b. of sulphur, and 281 b. of sodium thiosulphate. Two hundredweight of superphosphate contains about. 201 b. of sulphur. From the results obtained in this series some approximation of the rate of sulphur necessary can be determined, though no direct trials to evaluate the exact position have yet been made. The optimum . amount necessary is likely to lie somewhere between the amount supplied in 2cwt. of superphosphate (201 b. and the amount used in the 281 b. sulphur dressing. The amount is also likely to vary with certain soils and certain conditions on the same soil type, though as low as 101 b. to 201 b. of sulphur may give good responses. The trials begun in 1952 have shown that the 281 b. dressing of elemental sulphur is having a marked residual effect, as are the other treatments, though to a less degree. Future Work These responses to sulphur are being obtained on soils considered to be among the most highly fertile in the district. The deterioration in pastures on these soils in the past may have been due to a lack of sulphur or a gradual imbalance of sulphur with some other element or elements during the period in pasture. This imbalance can continue into at" least the first crop following pasture. The ultimate effect of the use of sulphur on these areas is difficult to

assess, but to those who have seen, and to those who have experienced the increases in pasture and crop production, it must obviously mean much, Superphosphate consists of approximately equal proportions of monocalcium phosphate and calcium sulphate. Where it has definitely been shown that sulphur in the superphosphate has been solely responsible for increased plant growth some cheaper form of sulphur other than manufactured superphosphate should be sought, and investigation of the most economic form should be made. Where both sulphur and phosphate are deficient superphosphate is the best form of fertiliser to use.

Under moderate rainfall sulphur is usually readily lost by leaching and therefore on areas where heavy superphosphate dressings have been applied for many years, the effect from these dressings is now possibly coming from the sulphur and not from the phosphorus supplied. Much work is needed to study this matter and to define the extent of sulphur deficient areas. Investigative work in North Otago in the coming year will be concerned mainly with the testing of different sulphur-con-taining materials and the extension of these trials to other soil types in the district.

JI Book Review ij .-.-. t sc*nw»»gtjguKMKFßgaaHgpM m»v..

“Te Waimate’ : E. C. Studholme

ONE hundred years ago in July, Michael Studholme made his. compact with the Maori chief Huru Huru near the present site of Waimate and took up the run of the same name. The people of Waimate have been celebrating their centennial recently and the occasion is appropriate for the reissue of Edgar Studholme’s book “Te Waimate”.

This book is not only an account of the development of Waimate Station and the career of the Studholme brothers from 1854, but is a rich store of information on the earlier stages of pastoral farming in New . Zealand. Few men were better fitted to undertake this task than Edgar Studholme. Born in 1866, he spent his whole life until his death in 1949 at Waimate. The history of this run epitomises, as Acland pointed out in his “Early Canterbury' Runs”, the story of squatting in Canterbury, and the successes and failures of the Studholme brothers typify the career of many of the pioneer runholders.

Rapid Progress

Compared with the progress of many places in the North Island, that at Waimate was fairly rapid and the Studholmes were encouraged to take up several other runs in both islands. But though conditions may have been a little easier than elsewhere, the development of a station the size of Waimate was an immense task. Not only was it stocked and fenced and much of the easier country ploughed up and sown in English grasses, but the lower-lying parts were drained at heavy cost and today form some of the most fertile land in the country.

At Waimate in the 1880 s not only were 40.000 to 50,000 sheep carried, but about 5000 acres were sown in crops—wheat, oats, and turnips. At that time the cropping was even more important than, the stock and on some of the best land very high yields were obtained. Edgar Studholme was a keen observer of the local scene. He wrote with affection of some of the men who worked at Waimate, picturesque characters of a type that has long since disappeared. He was also an observer of nature, and his chapters on the changing face of the landscape are among the most inter esting in the book. Frequent burning, prolonged hard grazing, and the replacement of native by introduced grasses, have not only changed the vegetative cover, but have had a profound effect on bird and animal life. Many people may have observed these changes over the years, but Edgar Studholme was one of the few who left a record of them. —P.R.S. A. H. and A. W. Reed. 30s.