366 THE INDIAN JOURNAL OF VETERINARY SCIENCE AND ANIMAL HUSBANDRY [III, IV.

Brunnich (9) analysed a large number of grasses from the pastoral areas in
sub-tropical Qeensland, where the rainfall has a marked summer incidence. Thirty-
eight samples of pasture grasses of various species, taken mostly in the growing
stage, gave a mean value of 1.5 per cent. nitrogen and .46 per cent. phosphoric acid.
Forty samples of old grass from similar areas gave mean values of .56 per cent. nitro-
gen and .16 per cent. phosporic acid. Four samples of grass hay conserved in stacks,
gave values of 1.1 per cent. for nitrogen and .336 per cent. for phosphoric acid.
The mean values for fifteen samples of Mitchell and Flinders grass taken in various
centres in Western Queensland during a droughty period in 1927 were—nitrogen .87
per cent. and phosphoric acid .20 per cent.

The results of analyses of pastures by the Rowett Institute (10) from Otjorn-
bindi, S.-W. Africa, show the following mean values for fen sepecies—nitrogen .43
per cent., phosphoric acid .065 per cent., potash .41 per cent. and soluble ash 1.89
per cent.

Samples of grass hay from British Somaliland and analysed at Rowett Institute
gave nitogen .86 per cent., phosphoric acid .24 per cent. and soluble ash 3.07 per
cent. Low values for nitrogen, phosphorus and soluble ash have also been recorded
by Orr (11) for Athi Plains, Makura and Molo in Kenya.

These analyses, representing pasture species and mixed pastures in regions of
summer rainfall (tropical and sub-tropical), show that the values for nitrogen,
phosphoric acid and silica-free ash are strikingly lower than those recorded by
Godden for pastures of Britain (Table 1), and very much lower than a series of
analyses of Kent pastures by Woodman (12) of Cambridge. These latter showed a
range of nitrogen 3.5 to 4 per cent., phosphoric acid .75 to .98 per cent., lime .79 to
1.21 per cent. and potash 3.9 to 4.1 per cent.

It would thus appear, from such records as are available, that the protein and
mineral content of pastures from tropical and sub-tropical areas are, in general,
lower than those recorded for pastures in cold temperate regions.

Pastures in Britain are more intensively grazed than those of countries of
summer rainfall and winter drought. Moreover, tropical and sub-tropical pastures,
in comparison with those of temperate countries, are notably poor in leguminous
components, which normally have a high protein content.

It may be that climatic factors, apart from those already discussed, affect the
protein and mineral contents of a pasture; and it is proposed to show that the
difference in mineral content of pastures in tropical and temperate regions may be
caused by a differential effect of climate on the rate of nitrogen and mineral uptake