Nutritive Value of Pasture. VII. The Influence of the Intensity of Grazing on the Yield, Composition and Nutritive Value of Pasture Herbage (Part III).

Abstract

The object of this series of investigations is to secure detailed information concerning the composition, digestibility and nutritive value of pasture herbage in its different stages of growth. The results which were obtained in these respects by cutting the herbage of the experimental pasture plot at weekly, fortnightly and 3-weekly intervals have been described in previous communications. During the seasons of the present investigations (1929 and 1930), the trials have been carried a stage further by the adoption of a system of cutting at monthly intervals. The results, therefore, are invested with special significance, in that a period of four weeks has been tentatively adopted in this country as the interval which is allowed to lapse, in rotational grazing practice, between successive grazings of pasture enclosures.

Nutritive value of pasture. VIII. The influence of intensive fertilising on the yield and composition of good permanent pasture (seasons 1 and 2) (With three diagrams.)

“…The cold, dry spring and the droughty summer of 1929 and the mild spring and regular summer rainfall of 1930 have already been described. These conditions are reflected in the yields from the pasture in the two years, the results affording striking confirmation of the finding in earlier investigations (2) as to the dominant importance of a regular distribution of rainfall in determining the yield of pastures under a rotational system, where a continuous growth of new herbage is required.…”

“…This marked difference was not connected with manurial treatment, since it was characteristic of the herbage from all the sub-plots irrespective of the system of fertilising. Similar behaviour was also noted in an investigation carried out in 1929 and 1930 on pasturage of an entirely different type (2). It was concluded that the effect was due to the very distinctive weather conditions of the two seasons, the 1929 season being a period of slow and retarded growth, consequent on the droughty conditions which prevailed, whereas 1930, with its unusually favourable meteorological conditions, was a season of exceptionally quick growth and pronounced vegetative activity.…”

“…Only in the case of the herbage from sub-plot Cll was there a definite fall, although this feature was not shared by the C sub-plots in Sections I and II. A very pronounced falling-off would have been anticipated on the basis of the results from another experimental pasture in the same season, where the crude protein in the dry matter of the monthly mown herbage fell to 13-63 per cent, during late September (2). In the latter case, however, the pasture was situated on a light, sandy soil, so that the herbage suffered severely from lack of moisture during the drought, becoming entirely "scorched" and brown in appearance.…”

A Comparison between rotational grazing and set stocking with ewes and lambs at three stocking rates

“…THE objective of a rotational grazing method of grassland management compared to set stocking is to control the frequency of defoliation and by this means achieve a higher total level of herbage production (Woodman, Norman and French, 1931) and utilization. Higher animal production per hectare however can only be expected from rotational grazing if (a) the stocking rate is such that any extra grass produced is consumed and not wasted and (b) the productive animal, i.e.…”

The Mechanism of Cellulose Digestion in the Ruminant Organism. III. The Action of Cellulose-Splitting Bacteria on the Fibre of Certain Typical Feeding Stuffs

“…Additional force is lent to this conclusion by the findings of separate investigations into the digestibility of pasture herbage in its different stages of growth, the following quotation (12) serving to make the argument clear: " It is clear, if the argument be based on the findings of the 1930 investigation, that fibre production may go on in growing herbage until the amount is as high as 24 per cent, of the dry matter, without the chemical character of the fibre undergoing alteration. Throughout this period, the digestible form of cellulose only is being elaborated in the herbage plant.…”