Talks on Manures Part 56

"Nitrate of soda," said I, "at the prices named, is only 2 to 2 cents per lb., and the nitrogen it contains would cost less than 18 cents per lb., instead of 24 cents, as given by Prof. Johnson."

"No. 1 Peruvian Guano, 'guaranteed,' is now sold," said the Doctor, "at a price per ton, to be determined by its composition, at the following rates: _Value per pound._ Nitrogen (ammonia, 17 c.) 21 c.

Soluble phosphoric acid 10 c.

Reverted " " 8 c.

Insoluble " " 2 c.

Potash, as sulphate and phosphate 7 c.

"The first cargo of Peruvian guano, sold under this guarantee, contained:

_Value per ton_.

Ammonia 6.8 per cent $23.80 Soluble phosphoric acid 3.8 " " 7.60 Reverted " " 11.5 " " 18.40 Insoluble " " 3.0 " " 1.20 Potash 3.7 " " 5.55 ------ Estimated retail price per ton of 2,000 lbs. $56.55 Marked on bags for sale $56.00

The second cargo, sold under this guarantee, contained:

_Value per ton_.

Ammonia 11.5 per cent $40.50 Soluble phosphoric acid 5.4 " " 10.80 Reverted " " 10.0 " " 16.00 Insoluble " " 1.7 " " .68 Potash 2.3 " " 3.45 ------ $71.43 Selling price marked on bags $70.00

"It is interesting," said I, "to compare these a.n.a.lyses of Peruvian guano of to-day, with Peruvian guano brought to England twenty-nine or thirty years ago. I saw at Rothamsted thirty years ago a bag of guano that contained 22 per cent of ammonia. And farmers could then buy guano guaranteed by the dealers (not by the agents of the Peruvian Government), to contain 16 per cent of ammonia, and 10 per cent of phosphoric acid. Price, 9 5s. per ton of 2,240 lbs.--say $40 per ton of 2,000 lbs.

The average composition of thirty-two cargoes of guano imported into England in 1849 was as follows:

Ammonia 17.41 per cent.

Phosphoric acid 9.75 " "

Alkaline salts 8.75 " "

At the present valuation, adopted by the Agents of the Peruvian guano in New York, and estimating that 5 per cent of the phosphoric acid was soluble, and 4 per cent reverted, and that there was 2 lbs. of potash in the alkaline salts, this guano would be worth:

Value per ton of 2,000 lbs.

Ammonia 17.41 per cent $60.93 Soluble phosphoric acid 5.00 " " 10.00 Reverted " " 4.00 " " 6.40 Insoluble " " .75 " " .30 Potash 2.00 " " 3.00 ------- $80.63 Selling price per ton of 2,000 lbs. $40.00

Ichaboe guano, which was largely imported into England in 1844-5, and used extensively as a manure for turnips, contained, on the average, 7 per cent of ammonia, and 14 per cent of phosphoric acid. Its value at the present rates we may estimate as follows:

Ammonia, 7 per cent $26.25 Soluble Phosphoric acid, 4 per cent 8.00 Reverted " " 10 " 16.00 ------ $50.25 Selling price per ton of 2,000 lbs. $21.80

The potash is not given, or this would probably add four or five dollars to its estimated value.

"All of which goes to show," said the Deacon, "that the Peruvian Government is asking, in proportion to value, from two to two and a half times as much for guano as was charged twenty-five or thirty years ago.

That first cargo of guano, sold in New York under the new guarantee, in 1877, for $56 per ton, is worth no more than the Ichaboe guano sold in England in 1845, for less than $22 per ton!

"And furthermore," continued the Deacon, "from all that I can learn, the guano of the present day is not only far poorer in nitrogen than it was formerly, but the nitrogen is not as soluble, and consequently not so valuable, pound for pound. Much of the guano of the present day bears about the same relation to genuine old-fas.h.i.+oned guano, as leached ashes do to unleached, or as a ton of manure that has been leached in the barn-yard does to a ton that has been kept under cover."

"True, to a certain extent," said the Doctor, "but you must recollect that this 'guaranteed' guano is now sold by a.n.a.lysis. You pay for what you get and no more."

"Exactly," said the Deacon, "but what you get is not so good. A pound of nitrogen in the leached guano is not as available or as valuable as a pound of nitrogen in the unleached guano. And this fact ought to be understood."

"One thing," said I, "seems clear. The Peruvian Government is charging a considerably higher price for guano, in proportion to its actual value, than was charged 20 or 25 years ago. It may be, that the guano is still the cheapest manure in the market, but at any rate the price is higher than formerly--while there has been no corresponding advance in the price of produce in the markets of the world."

POTASH AS A MANURE.

On land where fish, fish-sc.r.a.p, or guano, has been used freely for some years, and the crops exported from the farm, we may expect a relative deficiency of potash in the soil. In such a case, an application of unleached ashes or potash-salts will be likely to produce a decided benefit.

Clay or loamy land is usually richer in potash than soils of a more sandy or gravelly character. And on poor sandy land, the use of fish or of guano, if the crops are all sold, will be soon likely to prove of little benefit owing to a deficiency of potash in the soil. They may produce good crops for a few years, but the larger the crops produced _and sold_, the more would the soil become deficient in potash.

We have given the particulars of Lawes and Gilbert's experiments on barley. Mr. Lawes at a late meeting in London, stated that "he had grown 25 crops of barley one after the other with nitrogen, either as ammonia or nitrate of soda, but without potash, and that by the use of potash they had produced practically no better result. This year (1877), for the first time, the potash had failed a little, and they had now produced 10 or 12 bushels more per acre with potash than without, showing that they were coming to the end of the available potash in the soil. This year (1877), they obtained 54 bushels of barley with potash, and 42 bushels without it. Of course, this was to be expected, and they had expected it much sooner. The same with wheat; he expected the end would come in a few years, but they had now gone on between 30 and 40 years. When the end came they would not be sorry, because then they would have the knowledge they were seeking for."

Dr. Vlcker, at the same meeting remarked: "Many soils contained from 1 to 2 per cent of available potash, and a still larger quant.i.ty locked up, in the shape of minerals, which only gradually came into play; but the quant.i.ty of potash carried off in crops did not exceed 2 cwt. per acre, if so much. Now 0.1 per cent of any const.i.tuent, calculated on a depth of six inches, was equivalent to one ton per acre. Therefore, if a soil contained only 0.1 per cent of potash, a ton of potash might be carried off from a depth of 6 inches. But you had not only 0.1 per cent, but something like 1 per cent and upwards in many soils. It is quite true there were many soils from which you could not continuously take crops without restoring the potash."

"In all of which," said the Doctor, "there is nothing new. It does not help us to determine whether potash is or is not deficient in our soil."

"That," said I, "can be ascertained only by actual experiment. Put a little hen-manure on a row of corn, and on another row a little hen-manure and ashes, and on another row, ashes alone, and leave one row without anything. On my farm I am satisfied that we need not buy potash-salts for manure. I do not say they would do no good, for they may do good on land not deficient in available potash, just as lime will do good on land containing large quant.i.ties of lime. But potash is not what my land needs to make it produce maximum crops. It needs available nitrogen, and possibly soluble phosphoric acid."

The system of farming adopted in this section, is much more likely to impoverish the soil of nitrogen and phosphoric acid than of potash.

If a soil is deficient in potash, the crop which will first indicate the deficiency, will probably be clover, or beans. Farmers who can grow large crops of red-clover, need not buy potash for manure.

On farms where grain is largely raised and sold, and where the straw, and corn-stalks, and hay, and the hay from clover-seed are retained on the farm, and this strawy manure returned to the land, the soil will become poor from the lack of nitrogen and phosphoric acid long before there would be any need of an artificial supply of potash.

On the other hand, if farmers should use fish, or guano, or superphosphate, or nitrate of soda, and sell all the hay, and straw, and potatoes, and root-crops, they could raise, many of our sandy soils would soon become poor in available potash. But even in this case the clover and beans would show the deficiency sooner than wheat or even potatoes.

"And yet we are told," said the Deacon, "that potatoes contain no end of potash."

"And the same is true," said I, "of root-crops, such as mangel-wurzel, turnips, etc., but the fact has no other significance than this: If you grow potatoes for many years on the same land and manure them with nitrogenous manures, the soil is likely to be speedily impoverished of potash."

"But suppose," said the Deacon, "that you grow potatoes on the same land without manure of any kind, would not the soil become equally poor in potash?"

"No," said I, "because you would, in such a case, get very small crops--small, not from lack of potash, but from lack of nitrogen. If I had land which had grown corn, potatoes, wheat, oats, and hay, for many years without manure, or an occasional dressing of our common barnyard-manure, and wanted it to produce a good crop of potatoes, I should not expect to get it by simply applying potash. The soil might be poor in potash, but it is almost certain to be still poorer in nitrogen and phosphoric acid."

Land that has been manured with farm-yard or stable-manure for years, no matter how it has been cropped, is not likely to need potash. The manure is richer in potash than in nitrogen and phosphoric acid. And the same may be said of the soil.

If a farmer uses nitrogenous and phosphatic manures on his clayey or loamy land that is usually relatively rich in potash, and will apply his common manure to the sandy parts of the farm, he will rarely need to purchase manures containing potash.

CHAPTER XL.

RESTORING FERTILITY TO THE SOIL.

By Sir J. B. Lawes, Bart., LL.D., F.R.S., Rothamsted, Eng.

A relation of mine, who already possessed a very considerable estate, consisting of light land, about twenty years ago purchased a large property adjoining it at a very high price. These were days when farmers were flouris.h.i.+ng, and they no more antic.i.p.ated what was in store for them in the future, than the inhabitants of the earth in the days of Noah.

Times have changed since then, and bad seasons, low prices of wheat, and cattle-disease, have swept off the tenants from these two estates, so that my relation finds himself now in the position of being the unhappy owner and occupier of five or six farms, extending over several thousand acres--one farm alone occupying an area of two thousand four hundred acres. Fortunately for the owner, he possesses town property in addition to his landed estates, so that the question with him is not, as it is with many land owners, how to find the necessary capital to cultivate the land, but, having found the capital, how to expend it in farming, so as to produce a proper return.

It is not very surprising that, under these circ.u.mstances, my opinion should have been asked. What, indeed, would have been the use of a relation, who not only spent all his time in agricultural experiments, but also pretended to teach our neighbors how to farm on the other side of the Atlantic, if he could not bring his science to bear on the land of an adjoining county! Here is the land--my relation might naturally say--here is the money, and I have so much confidence in your capacity that I will give you _carte-blanche_ to spend as much as you please--what am I to do?