A TOP-DRESSING TRIAL ON POOR PASTURE ON LIGHT LAND IN CANTERBURY.

New Zealand Journal of Agriculture, Volume 47, Issue 5, 20 November 1933, Page 313

A TOP-DRESSING TRIAL ON POOR PASTURE ON LIGHT LAND IN CANTERBURY.

[Appendix to article, “ Establishment and Management of Permanent Pastures on the Light Lands of the Canterbury Plains,” published in the three preceding issues of this Journal.'] A. H. Flay, B.Sc., M.Agr.Sc., Canterbury Agricultural College, Lincoln. ' In 1929 a manurial or top-dressing trial was laid down on poor pasture on light land near Chertsey. In two adjacent fields areas of 2 acres each were fenced off and subdivided into half-acre sections. Thus there were (side by side along a water-race) eight half-acre sections, four on one type of pasture and four on another. Different fertilizers were used on each- plot. The grass growth was measured by controlled rotational grazing with sheep. The total number of sheep on the eight plots varied from two in the low-producing period, up to twenty in the “ flush ” of the growing season. Sheep were added to or taken out of the flock according to the estimated requirements. Ewes and lambs were used some of the time in the spring, but were equated to dry sheep. The greater portion of the grazing was carried out with dry halfbred ewes.

Like all top-dressing trials carried out on the half-field method this one has definite limitations. Carry-over from manured to control plots, and holding stock on unpalatable danthonia, brown-top, and Ch ewings fescue pastures, give the no-manure plots, without doubt, a higher figure for carrying capacity than they rightly deserve. These errors, unfortunately, could not be eliminated here.

Pastures manured. — Four plots treated on one field consisted of danthonia and trefoil, while those on the other field were originally a three-year run-out perennial rye-grass and red clover pasture, with Chewing’s fescue, brown-top, danthonia, hair-grass, and other inferior grasses invading. Some red clover and perennial rye still remained.

Manures used. Similar treatment was given to the plots in each field, (a) Danthonia pasture, (&) run-out pasture, as follows : — .

Plot No. Manure, Quantity per Acre. . . Date applied. 1. Nil .. ..’ .. .. .. .. Nil. 2. 5 cwt. carbonate of lime . .. .. .. .. July, 1929. 3. 1 cwt. superphosphate . . . . .. .. July, 1929.

Plot No. Manure, Quantity per Acre. Date applied. 3. i cwt. superphosphate .. . . .. .. April, 1930 1 cwt. superphosphate ' 'I . 5 cwt. carbonate of lime f '' ' ' .. ■■■ u & us ,1930 1 cwt. superphosphate .. .. .. .. April, 1931 1 cwt. superphosphate • . . . . . . . . August, 1931 1 cwt. superphosphate . . ...... April, 1932 1 cwt. superphosphate .. .. .. .. August, 1932 4. 1 cwt. superphosphate \ ■ 1 cwt. sulphate of ammonia J '' ....Jut, x 9 2 9 1 cwt. Nitrochalk, 1 cwt. superphosphate .. .. April, 1930 5 cwt. carbonate of lime, 1 cwt. superphosphate, and\ A , 1 cwt. Nitrochalk f ' ' Au g ust > T 93O 1 cwt. superphosphate, 1 cwt. Nitrochalk . . . . April, 1931. . 1 cwt. superphosphate, 1 cwt. Nitrochalk '.. .. August, 1931. 1 cwt. superphosphate .. . ... . . .. April, 1932. 1 cwt. superphosphate, 1 cwt. Calnitro.. . . . . August, 1932.

Note. — the (t?) series the superphosphate and lime plot — No. 3 — on better soil against the fence dividing the two main fields, and therefore not strictly comparable with the other plots. The lime plot of the (b) series is in a similar position on the other side of the original fence. Grazing Records. These are tabulated as follows :—

In order to show more, clearly the cumulative effect of top-dressing and rotational controlled grazing the average of the no manure, lime + super, and lime -f- super -j- nitrogen plots of the (a) and (6) series has been taken out as follows :—

By taking the percentage increase of the lime + super and lime -fsuper + nitrogen plots over the carrying capacity of the no-manure plots the following table has been prepared : —

If the total annual production be taken for the three years ending 31st August, 1932, and expressed as percentages of the no-manure plot the following is the table : —

Notes and Comments.

From the foregoing tables it may be seen that (i) there is an increase in carrying capacity from all manures over that of no manure ; (2) there is a cumulative effect from top-dressing for the first years of this experiment. The experiment is being continued. It will be interesting to follow this improvement to its conclusion.

For the three periods into which the grazing year has been divided there appears to be a steady improvement in production over all plots. Although there is a cumulative effect from annual top-dressing, this effect no .doubt is assisted by good grazing management. The improvement in the no-manure plots, although partially due to " carryover ” and grazing factors previously explained as interfering with an experiment of this type, must be assisted by good grazing management also. The increase in carrying capacity from one to three sheep per acre during the spring is valuable on fat-lamb-raising farms. The increase in winter production is also important. It will not be out of place to state here that during the very dry weather of December, 1931, and January and February, 1932, the sheep grazed on these plots were in better condition than those grazed on the farm pastures. The carrying capacity on the farm pastures was much lower than that on the plots.

It is not possible from such an experiment as this to determine the value of improvement in quality of the herbage, out-of-season grass, or the cumulative effect of top-dressing and grazing management. It is important to note that in these experiments (and the same has been noted on some other poor pastures), except for clover development, little change in the sward has taken place. The pastures are of practically the same composition to-day as they were over three years ago, the only difference being a denser plant covering and a greater response to favourable growth conditions on the manured plots. The nitrogen plots show a more dense grass covering than do the others.

The total and final value of manures may be difficult to calculate, but when the annual cost of manuring these plots is considered, the top-dressing of such pastures in comparison with the returns obtained, must be classed as unprofitable.

In the course of the farm’s cropping rotation such pastures should be ploughed up, cleaned, and properly sown down in permanent pasture of dominant cocksfoot or dominant true perennial rye-grass. Top-dressing with 1 cwt. superphosphate annually and 5 cwt. carbonate of lime every few years would then be worth while on such a pasture. Information is accumulating showing that from the net return point of view top-dressing good permanent pastures on well-managed lightland farms is profitable. This point is being investigated further.

The writer’s thanks are due to Mr. W. Halliday and the N.Z. Farmers’ Co-operative Association, Ltd., and latterly to Messrs. Campbell Bros., for allowing this experiment to be carried out on their property known as “ Selma.” Special thanks are due to Mr. T. Weir, manager of the estate, for the care, recording, and excellent grazing management carried out by him from the inception of the trial.

* In order to get a reasonable average figure for no manure in the (a) series the average of lime 4super and lime + super 4- nitrogen plots has been taken (compare average of Plots 3 and 4 for (&) series with no-manure plot of the same series). .

Plot. Manure. Dry Sheep per Acre grazed for Period. rst Sept.- Jan., Dry Sheep per Acre grazed for Period. 31st Jan., rst Feb.-3ist May, j ist Feb.~3ist May, 1st June~3ist Aug., j ist June-3 ist Aug., 1929-30.11930-31. 1930-31. 1931-32. 1931-32. 1932-33-1932-33- i93°1930. 1931. ! x 9j2. 1931- 19331932. i93°1933- I93I1930. 1932. 1 93 I - 1933I No manure. . . 1 ■ 69 i -6i 1-65 o-74 I- 08 O -76 0-08 0-27 o-68 2 Lime 1-41 2-oi • 1-76 o-59 1-78 1-51 0 • 18 0-27 0-97 3 Lime + super 0-79 • 62 3-14 5'57 o- 74 2-17 2 -26 0 -26 0-62 I -27 4 Lime + super + nitrogen 0 • 80 3-30 3-38 5’34 0-89 2'23 1-51 0-35 0-67 i -17

Table 1. —(1) Danthonia Pasture.

Dry Sheep per Acre grazed for the Period Plot. Manure. 1st Sept.31st Jan., | 1st Feb.31st May, ist June--31st Aug. 1929-30. 1930-31. 1931-32. I932-33-1 1930. i93i1932. 19331930. 19311932. 1933 I No manure I -26 2-88 2-33 3-52 0-50 1 * l6 I • 72 0 • 18 0-49 0-85 2 Lime 1-83 3-54 3-69 3-44 -27 2-45 2 -00 0 • 28 o-57 o-68 3 Lime + super I -22 . 3'25 3-37 • 16 0-44 2-04 1-26 0-27 0-00 -28 4 I.ime + super + nitrogen . 1-70 ■ 3’57 3' 6.3 4-79 0-78 2-03 1-24 0 • 67 0 • 67 1 • 14

Table 2. —(b) Run-out Pasture (Chewings Fescue, Frown-top, &c.).

Plot. Manure. . Dry Sheep per Acre grazed for the Period 1st Sept.~3ist Jan., 1st Feb.-3ist May, . 1st June-31st Aug., 1929-30. 1930-31. 1931-32. 1932-33. 1930. 19311932.11933: 1933- 1930. 1930. 19’31- i T 932. 1932. 11933 X933 Ai No manure* .. 0 • 80 1-69 I • 61 1-65 o-74 1 ■ 08 0 ■ 76 0-08 0-27 o-68 Bt No manure I -26 2-88 2-35 ■2-52 0-50 I • 16 I; 72 0 • 18 o-49 0-85 Totals 2 -05 4'57 3'51 4-17 I • 24 2-2 4 2-48 0 -26 • 76 i-53 Averages . . I -03 2-28 r-75 2 -08 0 • 62 I • 12 1-24 0-13 0-38 0 • 76 •• A3 Lime + super o-79 2-62 3’14' 5'57 o-74 2 • 17 2-26 0-26 0-62 1-27 b 3 Lime + super I -22 3-24 3'57 4 ■ 16 0'44 2-04 I -26 0-27 o-oo 1-23 Totals 2 -01 5'86 6 -71 9'73 1-18 4-21 .3'52 o-53 0 • 62 2-50 Averages ... I* OO 2'93 3'35 4-86 0'59 2 • II I • 76 0-27 0-31 1-25 a 4 Lime + super + nitrogen 0 • 80 3'30 3-38 5'34 0-89 2-23 I -51 0-35 0-67 I -17 b 4 Lime + super + nitrogen I • 70 3'57 3'65 4'79 c-78 2'03 -24 0 • 67 0 • 67 1 -i 4 Totals 2-50 6-87 7'03 10-13 r-67 4-26 2-75 I -02 1'34 2-31 Averages . . 1'25 3'44 3'52 5-06 0-84 2-13 1-38 0-51 ■ 67 I • 16

Table 3.

Manure. 1929-30. 1930-31-1931-32. 1932-33-Lime + super . . . • • Lime 4- super + nitrogen Per Cent. O 20 Per Cent. ■ 28 • .50’9 Per Cent. 91-40 101-14 Per Cent. I33-65 I43-23

Table 4. —Lime + Super, and Lime + Super + Nitrogen, Carrying Capacities shown as Percentage of Increase over No Manure for Period 1st September to 31st January.

Manure. 1929-30. 1930-31- . . 1931-32-Per Cent. Per Cent. Per Cent. Lime.+ super . . ' .. 2 ’ O 41-1 72-20 Lime + super -j- nitrogen . . Per Cent. 2 • O 38-9 Per Cent. 4 I-I 62-9 PerCent. 72-20 66-35

Table 5. Lime 4- Super, and Lime 4- Super 4- Nitrogen, Carrying Capacities shown as Percentage Increase over No Manure for Total Yearly Productions (Years ending 31st August).