5. Rye 20.03 12.15 Barley 17.44 10.65 Mangels 148.54 25.62 Hay 39.54 11.32 ------ ----- 225.55 59.74 The ratio of potash to phosphoric acid is 3.78 to 1. NOTE XVII. (pp. 253, 254). COMPOSITION OF FARMYARD MANURE (FRESH), (calculated by SIR JOHN LAWES). Phosphoric acid Total dry Total mineral calculated as Potash. Nitrogen. matter. matter. phosphate of lime. Percent 30.0 2.77 .50 .53 .64 Per ton (in lb.) 67.2 62.0 11.1 12.0 14.3 NOTE XVIII. (p. 232). THE URINE. An important consideration we have omitted to take note of in the text is the quantity of the urine voided. It is this consideration that renders the urine so much more valuable than the solid excreta. In the case of a man it has been estimated that the urine voided is fifteen times as much, is twelve times as rich in nitrogen, three times in potash, and two in phosphoric acid, as the solid excreta (Munro). The relation of solid matter in the case of the farm animals is not exactly similar. The urine of the ox is about twice the weight of its solid excreta. Both the horse and the sheep, however, void as a rule more solid excreta than urine. Munro, in his work on 'Soils and Manures,' contrasts the composition of the urine and solid excreta of the different farm animals by the following statement:-- 1 ton of urine contains 1 ton of solid excreta in lb.: contains in lb.: Nitrogen. Potash. Nitrogen. Cow 30 20 9 Horse 36 22 12 Sheep 38 30 16 FOOTNOTES: [181] Storer's 'Agricultural Chemistry,' vol. I. p. 496. [182] Scott's 'Manures and Manuring,' p. 19. CHAPTER VIII. GUANO. _Importance in Agriculture._ In the consideration of _artificial_ manures, guano deserves the first place. This it does mainly on historical grounds, as it is now largely a manure of the past. Not merely has it been used in agriculture to an extent to which no other artificial manure has as yet ever approximated, but its influence on agricultural practice has been enormous. Introduced into this country about the middle of the present century, it was the first of artificial manures to be used in large quantities.[183] It may be thus described as having introduced the modern system of _intensive_ cultivation, and given rise to the now almost universal practice of artificial manuring. _Influence on British Farming._