Studies of the Sulphur of Pasture Grass. I. The Cystine Content of Pasture Grass

Abstract

1. Organic sulphur determinations have been carried out on pasture grass at different stages of maturity. A decrease of about 39 per cent. was found in this constituent when the grass was cut for hay compared with the weekly and fortnightly stages of growth.2. The application of heavy dressings of inorganic sulphates to a good heavy clay permanent pasture produced an average increase of 8 per cent. in the organic sulphur content.3. No correlation was found between the organic sulphur and protein content of pasture grass, which suggests that the organic sulphur is present in part, at least, as non-protein sulphur.

Nutritive value of lucerne. I. Preliminary studies of yield, composition and nutritive value (Season 1932)

“…In investigations of the sulphur content of pasture herbage, Evans (14) found that the percentage of total sulphur (dry matter basis) averaged 0-72 per cent, (weekly cuts), 0-71 per cent, (fortnightly cuts) and 0-63 per cent, (monthly cuts), the figures for organic sulphur being 0-36, 0-36 and 0-32 per cent, respectively. It will be noted that the percentages of organic sulphur in the grass cuts were very similar to the mean value for the lucerne samples, but that the latter contained only about half the amount of sulphate sulphur found in the grass samples.…”

“…Evans (14) has shown that the cystine content of pasture herbage is low, averaging about 0-1 per cent, of the dry matter. Nevertheless, it is considered that this is sufficient to account, under English conditions, for wool growth in sheep subsisting wholly on pasturage (15).…”

“…The method is the same as was used by Evans in the case of grass (14) and depends on the assumption that cystine, either in the free or combined state, yields two-thirds of its sulphur as sulphide on treatment with alkali. Determinations were carried out on six samples of lucerne, five of which had been cut from different growths at the stage of flower and one at the budding stage.…”

The composition and nutritive value of marrow stem kale and thousand head kale

“…The amount of phosphoric acid, on the other hand, was but moderate (0-73 per cent.). The significance of these data will be better appreciated by comparing them with similar data for pasture grass (12,13), lucerne (14) and swedes(2). Table VII indicate absence of information.…”

“…During February, apart from a few slight night frosts, the weather was again mild and wet. Night frosts were encountered on the following dates during the period of the experiment: October 30, 31; November 1,2,8,13,14,20;December 17,22;January 7,8,9,10,11,12,13,16,27,28,29,30;February 6,7,8,9,10,23,24,26,27. It may be noted that the kale crops stood the winter remarkably well, and the plants remaining after the completion of the trials at the end of February were still green and healthy.…”