But it must be remembered that bone-dust furnishes nitrogen as well as phosphoric acid, and we are not warranted in ascribing the good effect of bones to phosphoric acid alone.
Bones differ considerably in composition. They consist essentially of gelatine and phosphate of lime. Bones from young animals, and the soft porous parts of all bones, contain more gelatine than the solid parts, or the bones from older animals. On the average, 1,000 lbs. of good commercial bone-dust contains 38 lbs. of nitrogen.
On the old dairy farms of Cheshire, where bone-dust produced such marked improvement in the quantity and quality of the pastures and meadows, it was usual to apply from 4,000 to 5,000 lbs. per acre, and often more. In other words, a dressing of bone-dust frequently contained 200 lbs. of nitrogen per acre—equal to 20 or 25 tons of barn-yard manure.
“It has been supposed,” said the Doctor, “that owing to the removal of so much phosphoric acid in the cheese sold from the farm, that the dairy pastures of Cheshire had been exhausted of phosphoric acid, and that the wonderful benefits following an application of bone-dust to these pastures, was due to its supplying phosphoric acid.”
“I do not doubt,” said I, “the value of phosphoric acid when applied in connection with nitrogen to old pasture lands, but I contend that the experience of the Cheshire dairymen with bone-dust is no positive proof that their soils were particularly deficient in phosphoric acid. There are many instances given where the gelatine of the bones, alone, proved of great value to the grass. And I think it will be found that the Cheshire dairymen do not find as much benefit from superphosphate as they did from bone-dust. And the reason is, that the latter, in addition to the phosphoric acid, furnished a liberal dressing of nitrogen. Furthermore, it is not true that dairying specially robs the soil of phosphoric acid. Take one of these old dairy farms in Cheshire, where a dressing of bone-dust, according to a writer in the Journal of the Royal Agricultural Society, has caused ‘a miserable covering of pink grass, rushes, and a variety of other noxious weeds, to give place to the most luxuriant herbage of wild clover, trefoil, and other succulent and nutritious grasses.’ It is evident from this description of the pastures before the bones were used, that it would take at least three acres to keep a cow for a year.”
“I have known,” says the same writer quoted above, “many a poor, honest, but half broken-hearted man raised from poverty to comparative independence, and many a sinking family saved from inevitable ruin by the help of this wonderful manure.” And this writer not only spoke from observation and experience, but he showed his faith by his works, for he tells us that he had paid nearly $50,000 for this manure.
Now, on one of these poor dairy farms, where it required 3 acres to keep a cow, and where the grass was of poor quality, it is not probable that the cows produced over 250 lbs. of cheese in a year. One thousand pounds of cheese contains, on the average, about 45½ lbs. of nitrogen; 2½ lbs. of potash, and 11½ lbs. of phosphoric acid. From this it follows, if 250 lbs. of cheese are sold annually from three acres of pasture, less than one lb. of phosphoric acid per acre is exported from the farm in the cheese.
One ton of timothy-hay contains nearly 14½ lbs. of phosphoric acid. And so a farmer who raises a ton of timothy-hay per acre, and sells it, sends off as much phosphoric acid in one year as such a Cheshire dairyman as I have alluded to did in fourteen years.
What the dairymen want, and what farmers generally want, is nitrogen and phosphoric acid. Bone-dust furnishes both, and this was the reason of its wonderful effects.
It does not follow from this, that bone-dust is the cheapest and best manure we can use. It is an old and popular manure, and usually commands a good price. It sells for all it is worth. A dozen years ago, I bought ten tons of bone-dust at $18 per ton. I have offered $25 per ton since for a similar lot, but the manufacturers find a market in New York for all they can make.