“Simply this,” said I. “We use a far greater amount of plant-food in the shape of manure than is removed by the crop of onions. And yet, notwithstanding this fact, it is found, as a matter of experience, that it is absolutely necessary, if we would raise a large and profitable crop, to manure it every year.”
A few experiments would throw much light on this matter. I should expect, when land had been heavily dressed every year for a few years, with stable-manure, and annually sown to onions, that 800 lbs. of sulphate of ammonia, or of nitrate of soda, or 1,200 lbs. of Peruvian guano would give as good a crop as 25 or 30 tons of manure. Or perhaps a better plan would be to apply 10 or 15 loads of manure, and 600 lbs. of guano, or 400 lbs. sulphate of ammonia.
[CHAPTER XXXV.]
MANURES FOR GARDENS AND ORCHARDS.
MANURE FOR MARKET-GARDENS.
The chief dependence of the market gardener must be on the stable-manure which he can obtain from the city or village. The chief defect of this manure is that it is not rich enough in available nitrogen. The active nitrogen exists principally in the urine, and this in our city stables is largely lost. A ton of fresh, unmixed horse-dung contains about 9 lbs. of nitrogen. A ton of horse-urine, 31 lbs. But this does not tell the whole story. The nitrogen in the dung is contained in the crude, undigested portions of the food. It is to a large extent insoluble and unavailable, while the nitrogen in the urine is soluble and active.
The market-gardener, of course, has to take such manure as he can get, and the only points to be considered are (1), whether he had better continue to use an excessive quantity of the manure, or (2), to buy substances rich in available nitrogen, and either mix them with the manure, or apply them separately to the soil, or (3), whether he can use this horse-manure as bedding for pigs to be fed on rich nitrogenous food.
The latter plan I adopt on my own farm, and in this way I get a very rich and active manure. I get available nitrogen, phosphoric acid, and potash, at far cheaper rates than they can be purchased in the best commercial fertilizers.
Pigs void a large amount of urine, and as pigs are ordinarily kept, much of this liquid is lost for want of sufficient bedding to absorb it. With the market-gardener or nurseryman, who draws large quantities of horse-manure from the city, this need not be the case. The necessary buildings can be constructed at little cost, and the horse-manure can be used freely. The pigs should be fed on food rich in nitrogen, such as bran, malt-combs, brewers’ grains, the refuse animal matter from the slaughter-houses or butchers’ stores, fish scrap, pea or lentil-meal, palm-nut cake, or such food as will furnish the most nitrogenous food, other things being equal, at the cheapest rate.