SHEEP GRAZING EXPERIMENT.

Otago Witness, Issue 3801, 18 January 1927, Page 12

SHEEP GRAZING EXPERIMENT.

As a rule soil does not deteriorate in fertility if it is left uncultivated and in a state of nature and is ungraded. Once, however, our virgin lands are “cropped,” whether in producing wheat or other corn .crop, or in the production

of meat, wool, or dairy products, there is, in course of time, a loss of fertility constituents. This waste, if waste it may be termed, must be restored to the land in 'order to ensure healthy stock conditions. The mortality among lambs today is a very live question, the causation of which has not yet been satisfactorily determined. The solution may range round the question whether the soil, through its herbage, is presenting as good a feed as formerly. In the manurial trials on grass lands it is often difficult to obtain results sufficiently evident to convince the average practical man. Increased bulk of vegetation is visible, but what about its quality? A’ botanical analysis of demonstration plois is helpful, but results stated in terms of beef, mutton, or other saleable products are more convincing. With this object in view a sheep farming experiment was conducted by F. Clarkson Howard to test the effects of phosphates

and phosphates with potash on pasture on a farm at Home. The sheep used were Dartmoor ewe hoggets, and the field had received no manurial dressing for some years. The Farmer and Stockbreeder describes the experiment thus: — Three plots of an acre each were pegged off, and on January 12, 1926, No. 1 plot received a dressing of 6cwt (30 per cent.)- superphosphate per acre; No. 2 plot -was treated with 6cwt (30 per cent.) superphosphate and 4cwt (14 per cent.) kainit per acre; No. 3 plot was untouched. During the early part of March there were visible signs of the manures acting, but exceptionally strong east winds experienced during April and May completely checked the growth of grass. In the neighbourhood generally there was more grass during March than in May. The plots were netted off, and on July 3 six sheep were put on each plot after the fasted live weight had been obtained. There was a perceptible difference in the kind of herbage on each plot, No. 2 having a very much better bottom of clovers and fine grasses. The behaviour of the sheep throughout the experiment was also carefully noted. The animals on No 2 plot spent more time lying down chewing the cud, and appeared generally more contented, while those on No. 3 plot were continually on the move, and gave the idea of having difficulty in obtaining sufficient food. On July 19 an extra sheep was added to each plot. Two sheep were' removed from No. 3 plot on August 10, and two smaller sheep added to the plot in their place on the same day. Owing to the effect of drought on the grass, two sheep had to be removed from each plot on August 20. The experiment had to be concluded on September 11, and the remaining five sheep on each plot were weighed, as the animals were required for breeding purposes. At this date Plot 1, and particularly Plot 2, still had a considerable amount of keep in them. The summary of the figures obtained during the experiment is given below: —

Total Loss — 25 Improvement due to Super over untreated s'.b Improvement due to Kainit and super over untreated Glib Improvement due to Kainit over super alone untreated 561 b

With regard to the weight of sheep first put on Plot 3, it was anticipated that this plot would not continue to carry so much head of stock as the other two plots, and two heavy sheep intended for the butcher were put on temporarily; but at the time of their removal it was felt that two smaller sheep could be added in their place. The two sheep then removed had gained a total of 81b. Of the sheep removed from all the plots on August 20, those from Plot 1 had gained a total of 61b, Plot 2 an increase of 121 b, and-Plot 3 a total loss of 51b. Subtracting lbs of sheep added to each plot from the lbs removed shows the following result : —Plot 1, loss of 201 b; Plot 2, gain of 361 b; Plot 3, loss of- 251 b. These totals, compared with each other, show slb improvement due to the use of 6ciwt superphosphate per acre alone over the untreated plot; but the application of 4cwt kainit per acre with the 6cwt superphosphate on Plot 2 gives 561 b, compared with the superphosphate alone on Plot 1, which, taken at the local value ,of Is Id per lb, becomes 60s Bd. The loss in weight on Plots - 1 and 3 showed that these plots were really overstocked,' which is not. surprising when they were carrying, on an average, six sheep to the acre. The important point

is that the plots were made to carry throughout an equal number of sheep per acre.

In examining the results of the experiments, it must be borne in mind that the figures are for 60 days only; but the effect of the manures will be considerable for some time to come, and further gain will be obtained before the manures are exhausted.

The experiment also affords a good example of the necessity of giving sheep a change, and providing them with a continuous supply of fresh, palatable fodder. From the quality of grass present, even., at the end of the experiment it was considered that the going back of the animals on Plot 1 and Plot 3 was not due to shortage of food. The reason was that the grass on the plots was mostly of a coarse kind, wliich the sheep did not appreciate, while the plot which received the Kainit was characterised by a close bottom of clovers, which continued to come up and spread and form a continuous source of palatable food for the sheep.

.5 C? o 2 Pm cc Weight of Sheep when put on plot. lbs. Weight of Sheep when put on plot. Date. Gain Loes lbs. Ibe. lbs. Bate. 1—D 141 July 3 145 Sept. 11 1 — 1—0 134 July 3 117 Sept. 11 .— 17 1—E 142 July 3 143 Sept. 11 I — 1—A 141 July 3 143 Sept. 11 2 — 1—o 121 July 3 126 Aug. 20 6 1—B 140 July 3 127 Sept. 11 —— 13 1- + 133 July 19 134 Aug. 20 1 — "" Total Loss — 30 2—0 114 July 3 118 Aug. 20 4 — 2—D 130 July 3 123 Sept. 11 —— 7 2—0 128 July 3 131 Sept. 11 3 — 2~+ 100 July 3 108 Aug. 20 8 2—E 139 July 3 137 Sept. 11 •—• 2 2—A 14G July 3 173 Sept. 11 27 2—B 118 July 19 121 Sept. 11 9 — Total Gain 36 — 3—D 138 July 3 123 Sept. 11 — 15 3—E 138 July 3 131 Sept. 11 —— 5 3—B 146 July 3 113 Sept. 11 3 3—T 132 July 3 128 Aug. 20* —— 4 3—P 105 July 3 104 Aug. 20 — 1 3—0 170 July 3 172 Aug. 10 2 — 3-4-170 July 19 176 Aug. 10 6 3—A 153 Aug. 10 149 Sept. 11 4 3—0 142 Aug. 10 .141 Sept. 11 — 1