THE WALLACEVILLE PASTURE EXPERIMENTS.

New Zealand Journal of Agriculture, Volume XVIII, Issue 1, 20 January 1919, Page 19

THE WALLACEVILLE PASTURE EXPERIMENTS.

The chemical composition of the forest soil compared with the adjoining danthonia pasture soil is interesting, as both no doubt were originally very similar in composition; but the destruction of the forest and its replacement has had a profound effect on the humus-content, the organic matter and nitrogen being much lower in the pasture soil. The lime-requirement method shows that larger quantities of carbonate of lime would be necessary for the forest soil than would be sufficient on the pasture soil.

G/245 : Collected 26/7/15 from front paddock adjoining road, gin. deep. G/246 : Collected 26/7/15 from septic-tank paddock, 4 in. to 9 in. deep.

METEOROLOGY.

It is interesting to note that, these experiments happen to coincide with a gradually increasing rainfall during the last three years, if one may accept the. figures obtained at the Whiteman’s Valley Meteorological Station, Silverstream, as being correct for Wallaceville. Silverstream Railway-station is only two miles from Wallaceville Railwaystation. Mr. B. V. Pemberton, Assistant Director of the Dominion ■Meteorological. Office, kindly supplies the figures which follow, showing the number of inches of rain, and rainy days, per month for the last three years. It will be noticed that the figures for November and December, 1918, of both the number of rainy days and . total rainfall are abnormally high compared with those of previous years, whereas the figures for the winter months July, -August, and September show a tendency in the. other direction. The rainfall this season being greater and more evenly distributed than usual was therefore much more favourable to the continuous growth of pasture on shallow soils.

THE SOIL-DRESSINGS DESCRIBED.

In the Wallaceville experiments some effort is being made to improve the feeding-capacity of the. pasture on these soils by top-dressing, the land. The general surface, save for the unevenness already mentioned, is level. . This area is a good sheep-grazing paddock in winter, but in summer the pasture is apt to dry to such ah extent as to be extremely liable to catch fire from sparks from the adjoining railway. The experimental paddocks, which are contiguous to the Wellington -Upper Hutt Railway line, near Wallaceville Station, were, through the courtesy of the Lands and Survey Department, laid off into SgL-acre plots, the subdivisions being made by sheep-netting. Five of these . paddocks, Nos. i to 5, were on shallow soil with numerous depressions in the surface, the pasture being mostly Danthonia pilosa, but, in addition, two other portions of the same size were fenced in from the adjoining area of the farm, which has been improved by ploughing and seeding with better grasses, among which cocksfoot, rye-grass, and clovers may be mentioned. From paddocks Nos. 6 and 7 danthonia had been largely displaced . by better pasture-plants. The pasture on these paddocks was obviously of much better quality than on the first five, the soil being deeper and the pasture of better composition, having been top-dressed with slag and superphosphate some years ago. The results of grazing these paddocks must therefore only be compared with the danthonia paddocks in a very limited way, really only the sheep and the climatic conditions being comparable. The top-dressings used were, — • ' •' -■.

(a.) Rough rubble limestone from the Mauriceville limeworks. This was the rough rejections from the Mauriceville quarry, which were of too mixed a nature either to burn into a quicklime or to use in any other way. It had accordingly accumulated for years on the hillside dump, and contained many large lumps of limestone as well as much fine material. It was purchased at 2s. per ton, and was trucked without bagging and railed free to the Upper Hutt Station, whence it was carted to the farm, one mile distant. . This material had the following mechanical composition:— . ‘ ■ ' . „ ' 1 ■ - Per Cent. . . .

Residue on 12 mm. '(about in.) sieve . . . . .. ■ 7-0 Passed 12 mm., retained on 5 mm. , . . . . ' . . 21-3 Passed 5 mm., retained on 2 mm. .. ... :.. 16-5 Passed 2 mm., retained on J - in. , ■ . . 1 . . . . 12-0 Passed Jj- in., retained on in. .. . '.. ... 19-7 Passed retained on Jg- in. . . . . . . « 15-4 Passed in., retained on in. . . . . . . 5-2 Passed in. . . t . . . . . . .. . 3-0

The amounts supplied to paddocks Nos. 3 and 4 were at the rate of 3 tons per acre, applied in August, 1915, when all the dressings were applied.

(&.) Finely ground Makatea Island rock phosphate containing about 85 per cent, tricalcic phosphate. ‘

(e.) Basic slag, Star brand, containing 17 per cent, phosphoric acid (P 2 O 5 ). . - ‘ ‘ ’ .... - U / • ' ■

(d.) Basic superphosphate : Mount Lyell superphosphate mixed with 15 per cent, slaked lime.

(g.) Finely ground carbonate of lime. This was obtained from the Mauriceville limeworks and was the commercial kiln-dried, and ground carbonate of lime sold by that works. The amount applied proved altogether inadequate to effect any appreciable results, and the paddock No. i may therefore. be regarded as an additional control paddock. One of the reasons for applying this was to compare it with the cheap unground limestone purchased at 2s. per ton. The cost of the various dressings per acre was therefore, — , ' - ■ • X ' £ s. d.

Paddock No. i: f ton fine carbonate of lime , .. ; . . - -. . 013 o Paddock No. 2 : Control. Paddock No. 3 : Dressing as on No. 4 plus 5 cwt. Makatea Island phosphate .. . . . . . . . . . . .. 1 19 6 Paddock No. 4 : Rough unground limestone at 2s. per ton and 3s. per ton cartage, and extra cost of spreading ... . . ... 015 o Paddock No. 5 : Ephos phosphate, 5 cwt., at £4 17s. 6d. per ton .. 146 .Paddock No. 6 : Basic superphosphate, 5 cwt., at per ton ... ... 15 o Paddock No. 7 : Basic slag, 5 cwt., at £5 10s. per ton . . ' ..176

BOTANICAL SURVEY OF THE PASTURE.

.' With the co-operation of Mr. A. H. Cockayne the assistance of Mr. E. Bruce Levy, Biological Assistant, was obtained to inaugurate a botanical survey of the Wallaceville pasture. The method used by Mr. Levy was that of Runkauer, which is recorded in the Plant Worldfor June, 1918. Briefly described, it may be stated that it consists in taking a note of the characters and occupants of a number of small areas in a paddock selected in such a way that the field is traversed by two paths which intersect at their centres. At equal distances along these paths an area of definite size (a few inches square) is selected, and a note taken of the names of every grass or character present. Assuming, that a . hundred of these areas are investigated (in practice it may be only necessary to take one-half or less of these), then the number of times in which a certain plant or character occurs may be set down, and gives the relative frequency of occurrence of that constituent or character in the pasture.

. The figures in the next table attempt to show the influence which dressings of limestone alone and limestone and phosphate together .are having on the danthonia pasture. • These data will be compared in the future with the area left to go to hay, but the present results are most instructive, as they tend to show that the poor native danthonia grass is reduced by dressings, of limestone and of the mixture of limestone and phosphates, and that the poor exotic grass, sweet vernal, is also somewhat diminished by these dressings. On the other hand, the valuable suck-ling-clover is increased by phosphate and limestone, while the valuable white clover is very greatly increased by phosphate and greatly by limestone. The valuable exotic crested dogstail is greatly increased by limestone and phosphate, • and more , greatly 'by limestone.; the valuable exotic cocksfoot is also much increased by phosphates and limestone. The deleterious moss is diminished by liming, and almost disappears with phosphates and limestone. Bare ground has almost disappeared with the aid of phosphates and limestone. The other figures do not call for any special- comment, save that perhaps the broad-leaved weeds are somewhat increased by the dressings.

Moisture ?. G/245. ' .. ... 3-98 G/246. 3-98 Loss on ignition . . . • • • • • • . 9-73 11-05 Total nitrogen . . 0-248 0-376 Hydrochloric-acid extract ... . . ' ... ■. . 0-248 0-376 Potash (K 2 O) ’ •• 0-358 0-340 Phosphoric acid (P 2 O 5 ) . . ' 0-074 0-093 . Lime (CaO) . . ... . . ... . . 0-301 0-364 Magnesia (MgO) 0-460 0-428 Citric-acid extract- . . . . . . . . 0-460 ■ 0-428 ' Potash (K 2 O) . . . . . . 0-020 0-027 Phosphoric acid (P2O5) . . . . 0-008 0-008

Other soils of the farm, from paddocks which have been ploughed, slagged, and grazed for several years and the pasture entirely altered, are as follows :

— a 05 rQ <D Ph 5 s April. g June. hi) A <D cn O > Q £ 8 Q Total. 1916. Inches.. 1-89 i-8i 0-85 3’6i 5-08 i-55 5-27 5-64 4-38 6-62 7-26 0-27 44’23 Days . . (10) (6) (9) (10) (17) (12) (14) (17) (12) (17) (n) (3) (138) 1917. Inches.. 2-52 i-59 1-29 5-67 7-41 7’14 8’37 5-21 6-58 4'39 1-82 3-28 55'27 Days . . (6) (9) (4) (10) (15) (10) (25) (20) (16) (17) (7) (10) (149) 1918. Inches.. 1-96 3’50 3-89 5’28 3’88 6-64 7’17 3’39 5'28 5 -6i 5-84 5’86 58-3O Days . . “O'. 00 . . . (7) | H tO M ?i<D OO o (8) Ch to '—'<O Jan. Ln 00- • M Feb. (II) S ■ S (8) Ln o '—kO (8) Mar. co o . o (13) co <>4 'r— m' April. (Si S (22) CO . H —' oo May. A 'h'S "h? S_£ June. s co bO to H • • (11) S 03 *° ■ July. >5 LU to o (II) 'O H ■ . (17) Aug. . fo 14 h (13) '--co (i7) Sep. S' (146) Oct. to ' O\ Nov. S (jrt o 6o S Dec. t '«' qo Si? . Total. Crr o ~—-cq

Rainfall and Rainy Days at Whiteman’s Valley, Silverstream.