MANURING FOR MILK.

Otago Witness, Issue 2924, 30 March 1910, Page 7

MANURING FOR MILK.

There are various methods of arriving at the influences of manures on grass land. The simplest and most common is to estimate the effects by weighing the crop from the different plots, and in ordinary circumstances this answers very well, though it has the defect that it docs not discriminate closely enough as to the quality of the herbage. Increasing experience in manuring investigations has led to greater importance being attached to the effectsof fertilising materials upon the composition of the herbage. The practised farmer knows that more bulk is of less significance than "a liberal proportion of the grasses and clovers relished by stock and effective in promoting growth and the formation, of flesh or the yield of milk. It was a recognition of the importance of qualify, as distinct from quantity, of produce that induced Dr Somerville some 12 or 15 years ,ago to institute -the practice of judging/ the relative merits of manurial dressings' on a given pasture by the effect on the animals pastured on the experimental plots. This ingenious system is not free from imperfections, as there is always the uncertain individual element, to be reckoned with, but it is perhaps as safe as any that could be devised.

This principle of testing the influences of manures bv the effect on the stock grazing> the land has been adopted in a different* form, at the Agricultural and Dairy College, Kingston, Derby. Being located im the centre of a dairying district, the Kingston authorities concluded that it would be more appropriate in their case to utilise dairy cows than fattening sheep or bullocks as mediums for reflecting the influences of the fertilisers. The plaa adopted was to graze dairy cows of,a si mi', lar type and milking capacity on the manured and unmanured enclosures, the two lots exchanging pastures fortnightly throughout the experimental period. T u p object of changing the cows periodically was to get rid of the individual clement and to make sure that whatever variation* in the yield were revealed could be attributable only io the influences of the grass. It should be mentioned 1 that only ona manurial mixture was tried, and that consisted of. 4ewt superphosphate and ljcwt sulphate of potash per acre. As the rtasture was previously of a poor description a dressing of lOcwt of ground lime per acre was given to both the manured and the unmanured portion, the lime being applied on April 10 and the artificial manures on April 12. The influence of the fertilisers soon became apparent both in the quantity and Quality of the herbage. The cows grazed thereon in the first fortnight gave a considerable increase of milk "over the other two, but the effect was even more striking when the animals exchanged pastures. Thai yield of the two transferred from th» - manured to the unmanured grass fell from 1147£1b to 798i1b. while the yield of tha other pair was increased from 10031 b to ] 0091 b. The next change was responsible for- a reduction of' more than 2501 b in the yield of the latter couple, while there was a slight increase from the two that wera restored to the manured portion. Thi9 zigzag course was followed with significant consistency, though the figures show howi difficult it is to induce cows that are once allowed to fall off in their milk to recover, the lost ground. There was no appreciable difference in the quality of the milk, ft result which i 3 In conformity with the modern idea concerning the influences of food upon the milk of the cow. Quality has been proved to be mainly a matter oß' heredity, the quantity alone being sensibly affected by feeding—that is, provided thd[ animals are maintained in good health*', The four acres that received artificial manure were so much more productive than the other four acres that a third was intxx>duced about tire middle of July*and from that time to the end of the ex« •periment in the second week of the manured plot carried the three as easily as the other plot did the two. In estimate, ing the financial results the manured plblf is, of course, credited with the milk of tht' third! cow, and on; this basis shows a buW | stantial profit. . The net increase of imili ; due to the influence of the manures wal, 84-. gallons per acre, whioh was obtained at a costi of 295, or 4£d per gallon). Hac the increase of milk been sold ati 6d pe* gallon the""pr<Sufc' would have been 13s pel acre, or, at 8d per gallon. 27s per acw§ so that ifc is clear that judioious manurLn? is a profitable proceeding. Mr Blaokshawyj the principal of the college, warns nil readers against the danger of drawing dg? ductioms from incomplete investigationa? and as this is the first year of the Kingston experiment it would be imprudent to ref gard the points referred to as establishes beyond doubt. At the same time thft* results are so striking aaid also so coni*

sietentr with reasonable -expectation" tb-vi there need be» little hesitation in accept *igthem as trustworthy.