Barnyard Manure.

King Country Chronicle, Volume III, Issue 134, 25 February 1909, Page 3

Barnyard Manure.

Th<- question ha:- often been discussed to what extent the pasturing of animals decreases the fertility of the foil. Professor Vivian has not dealt with this problem directly, but he ha* pointedly summed up the results of experiments in feeding stock, which have an important bearing on the subject. He shows, for instance, that , there is no loss of plant food with > mature animals, When the excrement, | both liquid and solid, can be preserved. If, he points out, the total dry matter i in the materials fed is determined, | and likewise that voided in the cxcroI ment, it will be found that the dry j matter in the excrement is just about ! one-half the amount that wis present ' in the food consumed, the greater part of the other half having been given off from the lungs as carbonic acid gas. If, on the other hand, the food is analysed to deterimne the nitrogen, phosphoric acid, and potash it contain?, and the excreta are also examined in the same way, it will be found that the entire amount of these constituents is voided by the animal in the liquid and solid excrement. While the excreta. therefore, contain only half of the total dry matter which was present in the ration, tney contain all the constituents that are generally considered to have fertilising value. These figures are not correct for young and growing animals, for the latter retain a certain proportion of the nitrogen and phosphoric acid for use in building up their bodies. "Recent experiments indicate that calves during the first three months of their lives retain in their bodies about one-third of the fertilising value of the food consumed, or in other words, the excrements from such animals contain two-thirds of the fertilising ingredients of the ration." In the case of the cow, another factor is introduced. A certain proportion of the nitrogen, phosphoric acid, and potash is removed in the milk. It has been estimated that a cow, giving an annual yield of 5,0001b., removes in the milk, fertilising materials amounting in value to about £l. Therefore, when the milk is sold, this amount of fertility is removed from the farm. If, on the other hand, butter only is sold, practically none is carried away, as all the valuable ingredients are found in skimmed milk. This, being an extremely interesting point, is not without its economic importance.