MANURIAL TRIALS WITH WHEAT AT CARTERTON.

New Zealand Journal of Agriculture, Volume XXVII, Issue 1, 20 July 1923, Page 44

MANURIAL TRIALS WITH WHEAT AT CARTERTON.

F. W. GREENWOOD,

B.A., Instructor in Agriculture, Wellington

For the past two seasons the Department has conducted a manurial trial with wheat on the farm of Mr. M. C. Jansen, at Carterton,, in the Wairarapa district. The ground selected for experiment was a fairly heavy loam having at a depth of from 9 in. to 12 in. an ironstone subsoil. The land was worked out of the lea, being skim-ploughed in June and cross-ploughed late in July, 1922. Lime in. the ground carbonate form was applied at the rate"of I-*- tons per acre in August on part of the area (plots 6 to 9). The wheat was sown early in September, the variety being Solid-straw Tuscan., Manure, where applied, was sown at the same time as the wheat, from the manurebox of the drill.

During the growing - period of the first season there were no marked differences to be seen among the various plots.. During the second season, however, when the same variety of wheat was sown, but neither lime nor manure again applied, marked differences were perceptible, as the following notes made in January, 1923, on the occasion of a farmers' field-day, will show —

Plot i, control : On this plot the crop is fair, except on one corner where the proximity to some gum-trees has accounted for the total absence of growth. Plot 2, Nauru, ground rock phosphate : The wheat on this plot has headed far better than has that on No. 1, where neither lime nor manure has been used. A much larger percentage of this wheat shows signs of rapidly approaching maturity. .

Plot 3, Nauru superphosphate : The growth of straw on this area has been prolific, but the wheat is less advanced.

Plot 4, Nauru ground rock mixed with superphosphate : From all appearances this is the best plot in the paddock. It is maturing evenly, has stooled excellently, is full in the head, and at the same time fairly fine in the straw.

Plot 5, control : This untreated plot was green as compared with the whiteness of the adjoining plot No. 4.

Plot 6, limed control : The wheat here was more advanced than on No. 5 but less so than on the manured plots.

Plot 7,' Nauru ground rock used after lime : The result on this plot, to all present appearances, is much better than that on No. 2, where rock phosphate was used alone.

Plot 8, superphosphate used after lime : This plot appears to be the next in quality to that on which the mixture of rock phosphate and superphosphate has been used.

Plot 9, limed control : This plot has a gentle slope, and the surface is much nearer to the ironstone than on other plots. Last year there were many patches upon which wheat did not grow at all. This year the whole plot is well covered, and the wheat crop is considerably better. This indicates that the lime is beginning to show its effects.

As already indicated, the soil of plot 1, being in close proximity to a group of gum-trees, is poorer than that of the adjoining plots. In the case of plot 9 the ironstone comes nearer to the. surface than it does on the other plots, owing to the fact that the surface soil slopes steeply away. The soil here, moreover, is wetter and sourer than is that of the adjoining plots. For'these reasons it-is evident that plots 1 and 9 cannot justly be compared with other plots in the paddock. The soil on. all the other plots is sufficiently uniform to allow of comparisons being made. It must be noted, however, that in the case of plot 9 (the limed control) the yield this season (34-4 bushels per acre) as compared with that of last season (25-4 bushels per acre) shows an advantage of slightly over 26 per cent. This is probably due to the fact that the lime is beginning to act in a place where its need was so manifest.

Apart from the difference secured in the latter instance, the results obtained from liming in this experiment are very inconclusive. The results obtained from Nauru rock and superphosphate do not show high margins over and above the untreated plot in the centre of the paddock. The most successful result is that obtained from the use of a mixture of 1 cwt. Nauru rock phosphate and | cwt. Nauru superphosphate.

It will also be noted that in every case the yields have been higher this year, when no manure was applied, than they were last season, when the land was ploughed out of the lea and both manure and lime were applied. It is evident that in the 1921-22 season the ground was somewhat too strong to admit of successful wheatgrowing.

Trials regarding the effect of Nauru phosphates on wheat have also been conducted on the farm of Mr. D. Smith, Masterton.

Plot. Treatment. Area. Season 1921-22 : Yield per Acre. Season 1922-23 Yield per Acre I Control . . Acre. I Bushels. 29-4 Bushels. 31-2 2 Nauru ground rock, i| cwt. I 36-1 4° 3 Nauru superphosphate, i-l-cwt. I 36-9 ■ ■ 4i-5 4 Nauru rock, i cwt., and Nauru super I 42’4 45-6 5 J cwt. Control . . 1 . 2 37-6 40-9 6 Limed control, 4 tons ' .. t 38-9 41’9 ’ 7 Nauru rock, i| cwt., and lime, rd- tons I 39'5 43’3 8 Nauru super, i| cwt., and lime, 11 tons I 37-x 42-1 9 Limed control, i| tons ' . . I 25-4 . 34’4

The yields obtained for the two seasons were as follows:-