WHEAT-MANURING EXPERIMENTS IN CANTERBURY, SEASON 1927-28.

New Zealand Journal of Agriculture, Volume XXXVI, Issue 5, 21 May 1928, Page 339

WHEAT-MANURING EXPERIMENTS IN CANTERBURY, SEASON 1927-28.

A. W. Hudson,

B.Agr.

B.Sc., Crop Experimentalist; R. A. Calder, B.Agr., 8.5 c.,,

Instructor in Agriculture; and E. M. Bates, B.Sc., Assistant Instructor in. Agriculture.

The co-operative experiments on wheat-manuring conducted in Canterbury during the past season, while continuing certain of the. objects of previous years, were designed to settle certain fundamental questions as. a forerunner to systematic extension of problems depending upon the basic ones. Following are examples of these fundamental questions : —•

(1) What is the best form of phosphate for wheat ? Before work on the best-paying quantity of fertilizer is carried out this question, must be settled. Obviously it is desirable to find out how much of an already determined, best kind of phosphate to apply, rather than to attempt to ascertain. what is the best quantity of a particular phosphate to apply without knowing whether it is the best kind or not. (2) Does potash influence the yield ? In the past, | cwt. of potash per acre has been used with, on the whole, no beneficial results. Is. | cwt. per acre sufficient to enable this question to be answered ? Certainly 1 cwt. per acre should give a decisive answer, and the larger quantity is now being used. (3) Does nitrogen justify its use ? Dried blood, a form of nitrogen, recognized as not so efficient as forms such as nitrate of soda and sulphate of ammonia, has been used mostly in the past. Its paying, use has been rather doubtful, while the other two. forms of nitrogen have generally shown better results where used. , Consequently the present work on nitrogen is being carried out with nitrate of soda at 1 cwt. per acre, a quantity considered sufficient to give a decisive answer as to whether nitrogen is of value or not.

If potash and nitrogen prove to be of paying use, the best quantity andparticularly in the case of nitrogen —the best time to apply are problems which will require solution. Seven of the main wheat-growing counties— Rangiora, Paparua, Malvern, Ashburton, Geraldine, and Waimate —were selected, and two experiments were conducted on a single farm in each district. The experiments are here designated "A” and “ B,” so that there was an A and a B experiment on each of the seven farms. •

MANURIAL TREATMENTS USED. These were as follows, the quantities given being at per-acre rate: — < ' Experiment A — . “ (1) No manure. (2) Superphosphate (44/46 per cent, tricalcic phosphate) . .. , .. 1 cwt. (3) Basic super (41/43 per cent, tricalcic phosphate) .. .. 1 cwt(4) Ephos phosphate (guaranteed 54 per cent, tricalcic phosphate) . . 1 cwt. (5) Nauru phosphate (about 80 per cent, tricalcic phosphate) ■. . 1 cwt. Experiment B—(1) Superphosphate . . . . . . .. > <. . .. 1 cwt, (2) Superphosphate 1 cwt., plus muriate of potash 1 cwt. . . . . 2 cwt. (3) Super 1 cwt., plus nitrate of soda 1 cwt. .... .. 2 cwt. (4) Super 1 cwt., plus muriate of potash 1 cwt., plus nitrate of soda 1 cwt. . . .. ... ... .. • • 3 cwt-

The nitrate of soda was applied as a top-dressing, in . September. All treatments were replicated ten times, and each plot was ; divided into two or three at harvest, giving from twenty to thirty determinations of yield. (The method of doing this work is described in the Journal for July, 1926, p. 6.) Solid-straw Tuscan was the variety used in every case, except at R. Patrick’s farm, Willowbridge. - NOTES ON TABLES. All results have been submitted to statistical examination. The differences between the treatments and the control plots are shown in heavy type when these differences are “ significant.” If the differences are “ non-significant,” the letters “ N.S.” are inserted. A difference is said to be significant when the chances as shown by statistical examination are greater than 30 to 1 in its favour. Hence .it can be said that a significant difference is one about which there can be no doubt. A non-significant difference, on the other hand, may be real enough, but it is too unreliable to be viewed with confidence. In Tables A the no-manure plot is used as the control for comparative purposes. Where superphosphate gives a significantly better yield than the other phosphates the fact is mentioned in the comments on the tables. In Tables B the superphosphate is used as the standard with which the other treatments are compared. As Experiments A and B were immediately alongside each other on each farm it is reasonable to suppose that the super in Experiment. B would have given about, the same increase over no-manure plots, had these been included, as it did in the adjoining experiment. Hence the net profit or loss shown by super in the A tables is carried down to the B tables, and forms the basis for comparison of return when potash and nitrogen are added to super. In all tables net profit is estimatedon a basis of ss. per bushel for wheat the increased monetary return after paying for manure at the following prices : Super, ss. pd. per cwt.; basic super, ss. 3d. ; Ephos phosphate, 6s. 6d. ; Nauru phosphate, ss. 6d. ; muriate of potash, 16s. ; nitrate of soda, 18s.

(1) Experiments on Farm of C. Mclntosh, Horrelville (Eyre). The paddock chosen had been in peas the previous season and in grass for two years before that. The plots were sown on 18th and 19th May, 1927, and harvested on Bth February, 1928. During the growing-period' August to October the superphosphate and basic super plots were slightly superior in growth to the remainder of the plots. Differences were most difficult to detect, with the exception of the plots on the B experiment, where the superphosphate drills' showed up well ahead a few weeks after sowing. The potash and super mixture delayed germination, and depressed it* to the extent of about 15. per cent., as compared with super alone. The nitrate of soda in the B experiment was applied on 26th September. The results are shown in Tables ia and 18. . »

Comments on Table ia : While the increases are small, they fully justify the use of three out of . four of the manures.

Comments on Table ib : Super is reckoned to carry the profit, asshown in Table ia. (The same procedure was adopted with other experiments, except No. 7.) The addition of potash to super has had no effect on yield, and the use of the mixture has resulted in a loss of Bs. gd. per acre. Although nitrate of soda has given a substantial increase of just over 3 bushels per acre, this has not been sufficient to meet the cost of the dressing, and the profit is reduced to 4s. gd. per acre. The superphosphate, potash, and nitrogen application shows a oss of Bs. gd. per acre. • ' ' "(2) Farm of Guy Bros., Fernside (Rangiora). At Fernside a paddock having grown peas in the preceding season, and wheat, peas,, and grass prior to that, was selected. The plots were sown on 26th and 27th May, 1927, and harvested on 30th January, 1928. . The superphosphate and basic super plots in Experiment A showed slightly better growth but lighter colour than the remainder. As will be seen from Table 2A,- the growth appearance did not indicate the yield differences. Here again potash in combination with super markedly depressed early growth, and germination again suffered to the extent of 16-5 per cent. The nitrate of soda was applied on 19th September, and, in spite of an already vigorous dark-green crop, it increased

growth and deepened the colour to a noticeable extent within a month of application. The results are given in Tables 2A and 28.

Comments on Table 2 a.: None of the phosphates affected the yield to a significant extent. This was rather surprising in view of the growth differences in the early stages. The results do not appear to conform to.the general experience on this land in other seasons, but certainly they are true enough for the paddock and season under review. ' .

Comments on Table 2B : The addition of potash to super has caused an increase in yield of 2-3 bushels per acre, which is not sufficient to pay for the costly application. The initial depressing effect of the potash on germination does not correspond with the effect on the'yield. Nitrate of soda, which looked markedly superior before the harvest, has caused a very considerable and profitable increase of just over 11 bushels per acre, and a resultant profit of £1 is. gd. from the use of the phosphate and nitrate. Whether the nitrate applied to crops not already dressed with phosphate would have brought about such an increase is problematical. The complete fertilizer treatment does not show as good a yield as the treatment just mentioned, and the profit is only 3s. 3d. per acre. 1 (3) Farm of F. W. Carpenter, Prebbleton (Paparua). The .previous crop on the paddock selected was potatoes, and for four years prior to the potato crop the paddock was in grass. The plots were sown on 6th and 7th July, 1927, and harvested on

6th February, 1928. From 30th August onwards the super and basic super plots in Experiment A showed a marked superiority in growth (see photo). Plots receiving potash in Experiment B showed a definite though slight "retardation in growth just after coming through the ground. Counts of plants showed no difference in the actual number of seeds germinating. Nitrate of soda was applied on 28th September, and its effect on colour and growth began to be apparent three weeks later. The yields are shown in Tables 3A and 38.

Comments on Table 3a : Superphosphate has given a very considerable increase of 8-i bushels per acre, with, a net profit of £1 14s. gd. Although the other phosphates have paid, the superphosphate yield is significantly higher than all others.

■ Comments on Table 3B : Potash has caused' a definite and significant depression in yield. Treatment 2 is less than treatment 1 by over 4 bushels per acre, and treatment 4 is less than treatment 3 by about the same amount. The effect on the financial aspect is highly unsatisfactory. On the other hand, the use of nitrate of soda has increased the yield to a paying extent. This is the third season in succession that nitrate of soda has given between 5 and 6 bushels per acre increase on this farm. • ‘ (4) Farm of D. Gillanders, Darfield (Malvern). A wheat crop preceded the experimental sowings on this paddock, which had previously to that been in grass for four years. The dates of sowing the plots were 24th and 25th May, 1927. As in the case of all the other experiments, no differences were visible just after the crop came through, but in early September . the superphosphate and basic super plots showed a marked superiority in growth over the Nauru and Ephos plots, which themselves were quite superior to the no-manure plots. The differences persisted until just before the crops came into ear, and after this differences were hard to detect. In Experiment B the delayed growth on the plots receiving potash was very marked, but counts revealed no difference in the actual number of seeds germinating. About three weeks after the application of nitrate of soda, on 29th September, its effect was much in evidence, and a marked superiority continued to the end of the growing-period. Tables 4a and 4B indicate the results.

Comments on Table 4A : All treatments show a paying increase over no-manure. Supei' has proved the most paying form of phos-

phate, and has given a highly significant increase over the other three phosphates.

Comments on Table 413 : Although potash added to super has caused an increase of 1-7 bushels over the super yield, it has not proved paying, reducing the net profit to ns. 3d. per acre. The super and nitrate-of-soda combination has proved greatly superior to super alone, with a resultant net profit of £2 6s. 3d. per acre. Treatment 4, while showing a considerable increase over super, has not yielded as well as treatment 3. The difference between treatment 3 and treatment 4 of 3-2 bushels is highly significant. This reduction in yield to below the super-plus-nitrogen yield when the potash is used in conjunction with super and nitrate of soda is difficult to account for, and as the same thing has occurred in several other experiments this season a further note is made on it later (page 349). (5) Farm of J. McAnulty, Methven (Malvern). The area selected for this experiment was in a paddock which had been in grass for six years before. The plots were drilled on 10th and nth June, 1927, and harvested on 13th February, 1928. At no stage in growth did the plots in Experiment A show any marked differences, although a careful examination revealed a slightly better growth on the super and basic super plots from September to December. On Experiment B the plots were very uniform in —there being no adverse effect from potash — three weeks after the application of nitrate of soda, when a distinct though slight effect was in evidence. The nitrate was applied on 27th September. Yields are given in Tables 5A and 58.

Comments on Table 5A : Super and basic super have each given practically equal and highly-paying increases over no-manure to the extent of more than 7 bushels. Nauru phosphate has failed to establish a significant increase in yield. Both super and basic super are significantly better than Ephos and Nauru.

Comments on Table 5B : No significance can be attached to the slight increase of super plus potash over the super alone, and the use of the potash must be regarded as a loss, thereby reducing the net profit to 14s. 3d. per acre. The increase due to nitrate of soda of nearly 5-f bushels per acre is quite a paying one, and the net profit of £1 19s. 3d. per acre is quite handsome. The failure of potash in the fourth treatment again reduces the profit. (6) Farm of J. Topham, Arowhenua (Geraldine). The crops preceding the wheat experimental plots were potatoes, white clover, and wheat. The plots were sown on 13th and 14th July, 1927, and harvested on 17th February, 1928. The crop looked remarkably well throughout, and in Experiment A there appeared to be a slight stimulation in growth on the super and basic super plots. In Experiment B the'nitrate was applied on 29th September, but no appreciable effect could be detected. The results are given in Tables 6a and 6b.

Comments on Table 6a : None of the manures has caused a significant increase in yield over no-manure.

Comments on Table 6b : All treatments (2,3, and 4) show better yields than super, but, with the exception of treatment 3, the losses .are greater than that when super alone was used. It should be noted that the. nitrate-of-soda increase of 4-3 bushels is worth £1 is. 6d., which is more than sufficient to pay for 18s. worth. Hence the loss is •occasioned by the super. Of course, it is not certain that the nitrate alone would have given so big an increase. Potash and nitrate as single additions to the super (treatments 2 and 3) give increases, but potash used in conjunction with super and the nitrate (treatment 4) has not been beneficial. The difference between Plots 3 and 4 is significant. The similarity to Table 4B should be noted. (7) Farm of J. Patrick, Willowbridge (Waimate). On this farm Experiment A followed rape in the rotation, and Experiment B followed wheat on the same paddock, which had previously been in barley and green feed (oats). Unfortunately, the crop in Experiment A lodged so badly as to preclude the possibility •of cutting the plots, and the experiment had to be abandoned. ■ At no stage during growth could differences be detected. On Experiment B the potash plots displayed a little of the delayed growth typical of most of the northern experiments. The nitrate of soda was applied •on 6th September, with no perceptible later effects. As Experiment A had to be abandoned, information regarding phosphates is not available, and no profit or loss is shown against super in Experiment B.

Comments on Table 7B : This table presents an interesting state of affairs. All additions to the phosphates have shown a loss, and

although potash and nitrogen individually added to super (treatments. 2 and 3) show no increase, when all three are applied a definite and significant increase is registered. This, however, is far from being paying. General Remarks and Summary. The season was particularly favourable for wheat-growing, with,, generally speaking, ample rainfall without any very serious overwet periods. The large yields evidence" the excellence of the season. PHOSPHATES. Four out of the seven experiments show paying increases from theuse of phosphates. Experiments 2,6, . and 7, where no phosphateresponse occurred, do not necessarily indicate that the districts in which these experiments were conducted are not responsive to phosphates. All that they tell us is that in the season of trial the areasselected did not respond. Further work in future seasons will enable a determination to be made of whether the present season’s resultsare typical or not. SUPERPHOSPHATE AND BASIC SUPER. These did not differ significantly in Experiments 1 and 5 '(Tables ia. and sa), but super established a definite superiority over basic super in Experiments 3 and 4 (Tables 3A and 4A). Superphosphate proved superior to' Ephos and Nauru in Experiments 3,4, and 5, and though the difference is not statistically significant in Experiment I it pointsin the same direction. It should be noted that, as in previous years, the greater the effect of phosphates in increasing yield the earlier the stage of ripening.. Experience has shown that where phosphate-treated cereals ripen before untreated a sure indication of an increase from the phosphate isobtained, although it does not follow that there is no increase where maturity is not hastened from the use of phosphates. Unfortunately,, however, most farmers view early maturity as what is commonly called. “ blighting-off.” • NITRATE OF SODA. The crops most likely to respond to spring application of solublenitrogenous fertilizer are those showing the all-to-common light-green, to yellowish-green colour. In selecting areas for the experiment no attempt was made toselect paddocks likely to specially respond to nitrogen, and it is.surprising • that such good response should have been obtained on. some of these fields. It is highly improbable that the high nitrogen response is altogether due to the peculiarities of the season, because this is the third year in succession that an increase of between. 5 bushels and 6 bushels per acre has occurred on Mr. Carpenter’s farm at Prebbleton (see Journal for September, 1927, p. 187, and August,. 1926, p. 111) as a result of using nitrogen in the spring. •

In addition to the foregoing experiment, Mr. Kennedy, of Springbank, Mr. Spence, of Mitcham, and Mr. H. Wilkinson, of Chertsey, all on lighter wheat-land, used nitrate of soda on small plots at the

Department’s request. On the two first-mentioned farmers’ paddocks the response was remarkable, and must have been between io bushels and 15 bushels per acre. There was a definite response on the lastmentioned farm also, but the plot was not inspected just before harvesting, and no close estimate could be formed of the result. Next ■.spring the Department intends to conduct a comprehensive further trial and demonstration of the use of soluble nitrogen as a , spring top-dressing for cereals. ' POTASH. Considerable diversity of results occurred with the use of potash. In five of the experiments there was an early retardation of growth, .and .in two of them definite harm to germination to the extent of 15 to 17 per cent, took place. The effect on yield did not correspond with the early effect on growth. In one experiment (3B) potash caused a definite depression in yield to the extent of over 4 bushels per acre when used with superphosphate on the one hand and with super plus nitrate of soda on the other. In three experiments (28, 48, and 6b) •potash added to super gave significant though non-paying increases. In all three nitrate of soda added to super gave paying increases, but potash -in combination with super and nitrate of soda showed a considerably lower yield than super plus nitrate. Two of these latter were highly significant, and the third, though non-significant, was no ■doubt real enough. The same order of things is apparent in Experiment 58, although the potash-plus-super increase and the potash-plus-super-plus-nitrate ■decrease, as compared with super plus nitrate, are not significant. The writers can offer no reason for this behaviour of the manures. There is not sufficient evidence from these experiments to warrant the recommendation of the use of potash on wheat. The valuable co-operation, and assistance so willingly given by ■farmers is much appreciated, and the assistance of Messrs. Hardy, Elliott, and Leitch, of the Fields Division’s staff, is duly acknowledged. The muriate of potash used in the experiments was kindly supplied free of charge by Dalgety and Co., -Ltd., Christchurch.

Noxious-weeds Order. — The Peninsula ■ County Council (Otago) has declared hemlock, burdock, gorse, and broom as noxious weeds, and Californian thistle as not a noxious weed, within that county.

The Ragwort Moth. At the April meeting of the Council of Scientific and Industrial Research the Acting-Chairman stated that after extended trials it had been decided by the Noxious Weeds Committee that a restricted permit only should be issued for the release of the ragwort moth Tyria jacobaeae. It was considered necessary to take the utmost precautions regarding all insect releases ; hence Tyria jacobaeae was placed out on ragwort areas in the immediate vicinity of the Cawthron Institute only. In the event ,of its ultimate safety being thoroughly ■proved, this action will render a large supply of insects available for more extended release next season. It is hoped that the outbreak of wilting-disease which has appeared, probably as a result of the restriction of the moths to a confined feeding-area, will not seriously diminish the number which will winter over and be available for release, if such a course is decided upon, at a later date.

Bushels per Acre. Net Profit or Loss Trea tment. Net Profit or Loss per Acre. Yield. Difference. •- (i) No manure . . • . . 52-9 • < (2) Superphosphate . . 55*5 2-6 Profit, 7s. 3d. (3) Basic super . . . . 55'7 2-8 Profit, 8s. pd. (4) Ephos phosphate 54’9 2-0 Profit, 3s. 6d. (5) Nauru phosphate 53’9 1-0 Loss, 6d.

Table IA. (Each yield is the average of 18 plots.)

Treatment. ' Bushels per Acre. • Net Profit or Loss' per Acre. Yield. Difference. (i) Superphosphate 58-2 Profit, 7s. 3d. (see Table ia). (2) Super plus muriate of potash. . . . 57'4 N.S. Loss, 8s. gd. (3) Super plus nitrate of soda ■ 61-3 3-1 Profit, 4s. gd. (4) Super plus potash and nitrate of soda 61-8 3-6 Loss, 8s. gd.

Table IB. (Each yield is the average of 18 plots.)

Bushels per Acre. Treatment. , . Bushels per Acre. Net Profit or Lc"S — Net Profit or Lets per Acre. Yield. Difference. t Difference. (i) No manure .. . . No manure . . . . 60-2 60-2 '(2) Superphosphate . . Superphosphate 6o-6 6o-6 N.S. ' N.S. Loss, 5s. gd. Loss, 5s. gd. '(3) Basic super . . e . . * ; . . Basic super ' ' 59’5 59‘5 N.S. N.S. Loss, 5s. 3d. Loss, 5s. 3d. (4) Ephos phosphate . . . . Ephos phosphate 59'2 59’2 .. N.S. N.S. Loss, 6s. 6d. Loss, 6s. 6d. (5) Nauru phosphate Nauru phosphate 6o-o 6o-o -. N.S. N.S. Loss, 5s. 6d. Loss, 5s. 6d.

Table 2A. (Each yield is the average of II plots.)

Bushels per Acre. per Acre. Treatment. Net Profit or Loss Net Profit or Loss per Acre. Yield. Difference. (i) Superphosphate . . 62-4 Loss, 5s. 9d. (2J Super plus potash ... 64-7 2-3 Loss, ios. 3d. (3) Super plus nitrate of soda 73’5 11-1 Profit, £1 is. gd. (4) Super plus potash plus nitrate of 71-0 8-6 Profit, 3s. 3d. soda

Table 2B. (Each yield is the average of 15 plots.)

Treatment. Bushels per Acre. Net Profit or Loss per Acre. Yield. Difference. (i) No manure . . . . ' . . 62-7 • (2) Superphosphate 70-8 8-1 Profit, £1 14s. pd. (3) Basic super . . . . - . . 69-3 6-6 Profit, £1 7s. gd. (4) Ephos phosphate 65-6 2-9 Profit, 8s. (5) Nauru phosphate 66-5 3-8 - Profit, 13s. 6d.

Table 3A. (Each yield is the average of 20 plots.)

Treatment. Bushels per Acre. Net Profit or Loss per Acre. ■ . Yield. ' Difference. (i) Superphosphate . 76-7 Profit, £1 14S. gd (2) Super plus potash’ . . 72’4 . - 4-3 Loss, 2s. gd. (3) Super plus nitrate of soda . . - 8i-8 5-1 Profit, £z 2s. 3d. (4) Super plus potash /plus nitrate of 77’2 N.S. Profit, gd. ■ soda ' • ’ .

Table 3B. (Each yield is the average of 18 plots.)

Treatment. Bushels per Acre. Net Profit or Loss per Acre. Yield. Difference. (1) No manure 40-2 (2) Superphosphate . . . . 45’1 4-9 Profit, 18s. gd. (3) Basic super . . . . ■ . . 42-8 2-6 Profit, 7s. gd. (4) Ephos phosphate 42-7 2-5 Profit, 6s. (5) Nauru phosphate ... 40-2 45-i. 42-8 . 42'7 43’4 4-9 2-6 3Profit, 18s. gel. Profit, 7s. 9d. Profit, 6s. Profit, ios. 6d.

Table 4A. (Each yield is the average of 26 plots.)

Treatment. Bushels per Acre. Net Profit or Loss per Acre. Yield. . Difference. (x) Superphosphate 45'4 Profit, 18s. gd. (2) Super plus potash . . 47’1 . 1’7 Profit, ns. 3d.. (3) Super plus nitrate of soda 54’5 9-1 Profit, 6s. 3d. (4) Super plus potash plus nitrate of 51'3 5-9 Profit, 15s. 3d. soda 45’4 47’1 54’5 51’3 1-7 9-1 5-9 Profit, 18s. gd. Profit, ns. 3d. Profit, £2. 6s. 3d. Profit, 15s. 3d.

Table 4B. (Each yield is the average of 22 plots.)

Treatment. Bushels per Acre. Net Profit or Loss per Acre. Yield. Difference. (i) No manure 67-7 (2) Superphosphate ' .. 74’9 7-2 Profit, £1 10s. 3d. (3) Basic super 75-° 7-3 Profit, £1 ns. 3d. (4) Ephos phosphate .. . 71-3 3-6 Profit, ns. 6d. (5) Nauru phosphate 68-3 N.S. Loss, 5s.. fid.

Table 5A. (Each yield is the average of 22 plots.)

Bushels per Acre. Net Profit or Loss Treatment. Bushels per Acre. Net Profit or Loss per Acre. Yield. Difference. (1) Superphosphate . . .'. (2) Super plus potash (3) Super plus nitrate of soda (4) Super plus potash plus nitrate of soda 6869- • 74’2 73'2 N.S. 5-4 4-4 Profit, -£i IOS. 3d. Profit, 14s. 3d. Profit, £1 19s. 3d. Profit, 18s. 3d.

Table 5B. (Each yield is the average of 20 plots.)

Treatment. . Bushels per Acre. Net Profit or Loss per Acre. Yield. Difference. (1) No manure . . 59’7 (2) Superphosphate . . 60-2 N.S. Loss, 5s. gd. (3) Basic super . . . . 6o-i N.S. Loss, 5s. 3d. (4) Ephos phosphate 597 N.S. Loss, 6s. 6d. (5) Nauru phosphate 59'7 60-2 6o-i 59’7 59’3 N.S. N.S. N.S. N.S. Loss, 5s. gd. Loss, 5s. 3d. Loss, 6s. 6d. Loss, 5s. 6d.

Table 6A. (Each yield is the average of 21 plots.)

Treatment. Bushels per Acre. Net Profit or Loss per Acre. Yield. Difference. (i) Superphosphate ... * 61-3 Loss, 5s. gd. (2) Super plus potash 62-9 1-6 Loss, 13s. gd. (3) Super plus nitrate of soda 65-6 4-3 Loss, 2S. 3d. (4) Super plus potash plus nitrate of 637 2-4 Loss, £1 7s. gd. soda 637 2-4 Loss, £1 7s. gd.

Table 6B. (Each yield is the average of 26 plots.)

Treatment. ■ Bushels per Acre. Net Profit or Loss per Acre. Yield. Difference. (i) Superphosphate 38-4 (2) Super plus potash 37'2 N.S. Loss, 16s. (3) Super plus nitrate of soda 37’6 N.S. Loss, 18s. (4) Super plus potash plus nitrate of 40-9 2-5 Loss, £1 is. 6d. soda

Table 7B. (Each yield is the average of 22 plots.)