Page:1902 Encyclopædia Britannica - Volume 25 - A-AUS.pdf/250

 206

AGRICULTURE

[UNITED’

that the amounts of increase assumed to be produced of the nitrogen of the food is retained by the animal, and are higher than those usually obtained. The amount so lost to the manure. And when, as is more and more estimated to be yielded by linseed cake, for example, is the case with early maturity, the increase comprises a certainly higher than would be obtained when, as is some- larger proportion of growth than in mere fattening, the times the case, it is given in such excessive amount that amount of the nitrogen of the food which will be lostmuch is voided by the animals undigested. On the to the manure will be between that given in the table other hand, the amounts of the different foods estimated and twice as much. The third section of the table relates to the phosphoricto be required to give one part of increase are doubtless higher than would be so required, if as large a proportion acid, and there are given for each food, as in the case of of the constituents were digested and utilised as has been the nitrogen, the amounts of it per cent, and per ton of shown to be digestible in the German experiments on that the foods; the amount estimated to be retained in the subject. In those experiments the animals were for the increase; the amount remaining for manure, and the most part kept on mere sustenance food, so that they money value of this at 2d. per ft). It will be seen that would digest the maximum proportion of the constituents there is only about two-thirds as much phosphoric acid they received. In the case of fattening, however, as of nitrogen retained in a given weight of fattening especially with early maturity, the conditions are very increase; but, owing to the very generally less, and somedifferent. The animal receives a greater or less excess of times much less, amount of it in the foods, a greater food, and not only voids proportionally more undigested, proportion of that consumed is retained in the animal, and but may transform more than is fully utilized. It is, a less proportion remains for manure. It should be added nevertheless, economy to give an excess within certain that, in the case of store animals and of animals still limits. The apparent waste is, in fact, more than growing, the amount of phosphoric acid retained in a counterbalanced. Thus, in the first place, the manure given weight of increase will be very much greater than in value of the not-utilized food still remains intact; but mere fattening; indeed, in mere store increase it may, as the real source of the economy is in the shortening of the in the case of the nitrogen, be nearly twice as great. Of potash, the table shows that a given weight of time of feeding, and so, at the cost of some excess of food, saving the amount that would be expended in the fattening increase retains only about one-eighth as much mere sustenance of the animal in feeding for a longer as it does of phosphoric acid ; and the percentage of the whole in the food which is lost to the manure is generally period. The next section of the table, headed “Nitrogen,” very small. In its case, as in that of the nitrogen and and comprising seven columns, relates to the amount phosphoric acid, the amount retained in mere store increase and to the distribution of the foods. There are given the will be nearly twice as much as in mere fattening increase,, amounts of nitrogen per cent, and per ton as in Table but the total quantity retained is still very small. The XXX.; the actual amount estimated to be contained in the potash remaining for manure is valued at l^d. per ft). The last column of the table shows the total manure increase in live weight of the animal consuming one ton of the food, and the - percentage of the total nitrogen value of a ton of each of the foods after consumption,, consumed which is so retained in the increase; the reckoning the nitrogen, the phosphoric acid, and the amount of the nitrogen of the food remaining for manure, the potash at the prices above named, which are those at amount of ammonia to which it corresponds, and its money which they could, at the time (1897-98), be purchased in value, reckoned at 4d. per 11). Throughout the calculations artificial manures. The reductions in the prices of amit is assumed that only fattening increase is produced, monia, phosphoric acid, and potash, now adopted, bring and that this will contain 8 per cent, of nitrogenous all the estimates of total or original manure value substance, corresponding to 1*27 per cent, of nitrogen in almost exactly one - third lower than those given in the increase. It will be seen that, according to the 1885. Thus the total value of a ton of linseed cake figures, the only food in the list of which a ton is consumed, which in 1885 was reckoned at £3, 18s. 6d., estimated to contribute more than 5 K> of nitrogen to the was taken in 1897-98 at £'2, 11s. lid.; that of a ton of fattening increase is linseed, and that in the case of none oats was reduced from <£1, 9s. lOd. to 19s. 9d.; and that of the cakes, or of the leguminous seeds, will 1 ton of other foods in the same proportion. Unexhausted Manure Value of Cattle Foods.—A much contribute 5 ft) of nitrogen to the increase, whilst the more complicated problem than the estimation of the total amount is in several cases under 4ft). A ton of the cereal grains, or of their products (and locust beans), or original manure value of cattle foods is that of estimatgenerally contributes under 4 ft); a ton of hay or straw ing the unexhausted manure value of the difterent foods, or less than half as much; and a ton of roots very much less what may be called their compensation value, after they still. To put it in another way: of the total nitrogen have been used for a series of years by the outgoing tenant, consumed in the foods rich in that substance, such as the and he has realized a certain portion of the manure value cakes and the leguminous seeds, there is generally less in his increased crops. In the light of experimental and than 5 per cent, retained in the fattening increase in live other evidence, Lawes and Gilbert fixed upon a scale of weight. The cereal grains, on the other hand, which are reduction, starting from the total or original manure value, much less rich in nitrogen, contribute a much larger as estimated in Table XXXI. The method so arrived at proportion of their total amount to the increase; indeed, is to deduct one-half of the original manure value of the generally about 10 per cent, of it. The gramineous straws food used the last year, and one-third of the remainder contribute a higher proportion still, whilst roots (mangels each year to the eighth, in the case of all the more conand turnips) lose by feeding on an average only about centrated foods, and of the roots; whilst, for the hays and 5 or 6 per cent, of their nitrogen. Hence, when fattening straws, which contain larger amounts of indigestible increase only is- produced, the proportion of the nitrogen matter, and the constituents of which will be more slowly of the food which is retained by the animal, and so lost to available for crops, two-thirds of the original manure valuethe manure, is very small in the case of the richer foods, is deducted for the last year, and only one-fifth from year but more in that of the poorer ones; but even with to year to the eighth year. The results of the estimates of them it seldom exceeds 10 per cent., excepting with the compensation value so made are given in Table XXXIT. straws. It may be assumed, however, that when the The first column shows the total or original manure value foods are consumed by store animals, about twice as much of each food. The second column shows the allowance