Talks on Manures Part 22

Composition of Soil, No. 2. (Bad Clover).

Water 17.24 Organic matter* 9.64 Oxide of iron and alumina 11.89 Carbonate of lime 14.50 Magnesia, alkalies, etc. 1.53 Insoluble silicious matter 45.20 ------- 100.00 ======= 2d determination.

* Containing nitrogen .306 .380 Equal to ammonia .370 .470

"Both portions of the clover-soil thus contained about the same percentage of organic matter, and yielded nearly the same amount of nitrogen.

"In addition, however, to the nitrogen in the clover-roots, a good deal of nitrogen, in the shape of root-fibres, decayed leaves, and similar organic matters, was disseminated throughout the fine soil in which it occurred, and from which it could not be separated; but unfortunately, I neglected to weigh the soil from a square yard, and am, therefore, unable to state how much nitrogen per acre was present in the shape of small root-fibres and other organic matters.

"Before mentioning the details of the experiments made in the next season, I will here give the composition of the ash of the partially cleaned clover-roots:

Composition Of Ash Of Clover-Roots, (Partially Cleaned).

Oxide of iron and alumina 11.73 Lime 18.49 Magnesia 3.03 Potash 6.88 Soda 1.93 Phosphoric acid 3.61 Sulphuric acid 2.24 Soluble silica 19.01 Insoluble silicious matter 24.83 Carbonic acid, chlorine, and loss 8.25 ------ 100.00 ======

"This ash was obtained from clover-roots, which yielded, when perfectly dry, in round numbers, eight per cent of ash. Clover-roots, washed quite clean, and separated from all soil, yield about five per cent of ash; but it is extremely difficult to clean a large quant.i.ty of fibrous roots from all dirt, and the preceding a.n.a.lysis distinctly shows, that the ash of the clover-roots, a.n.a.lyzed by me, was mechanically mixed with a good deal of fine soil, for oxide of iron, and alumina, and insoluble silicious matter in any quant.i.ty, are not normal const.i.tuents of plant-ashes. Making allowance for soil contamination, the ash of clover-roots, it will be noticed, contains much lime and potash, as well as an appreciable amount of phosphoric and sulphuric acid. On the decay of the clover-roots, these and other mineral fertilizing matters are left in the surface-soil in a readily available condition, and in considerable proportions, when the clover stands well. Although a crop of clover removes much mineral matter from the soil, it must be borne in mind, that its roots extract from the land, soluble mineral fertilizing matters, which, on the decay of the roots, remain in the land in a prepared and more readily available form, than that in which they originally occur. The benefits arising to wheat, from the growth of clover, may thus be due partly to this preparation and concentration of mineral food in the surface-soil.

"The clover on the hillside field, on the whole, turned out a very good crop; and, as the plant stood the winter well, and this field was left another season in clover, without being plowed up, I availed myself of the opportunity of making, during the following season, a number of experiments similar to those of the preceding year. This time, however, I selected for examination, a square yard of soil, from a spot on the brow of the hill, where the clover was thin, and the soil itself stony at a depth of four inches; and another plot of one square yard at the bottom of the hill, from a place where the clover was stronger than that on the brow of the hill, and the soil at a depth of six inches contained no large stones.

SOIL NO. 1. (CLOVER THIN), ON THE BROW OF THE HILL.

"The roots in a square yard, six inches deep, when picked out by hand, and cleaned as much as possible, weighed, in their natural state, 2 lbs.

11 oz.; and when dried on the top of a water-bath, for the purpose of getting them brittle and fit for reduction into fine powder, 1 lb. 12 oz. 31 grains. In this state they were submitted as before to a.n.a.lysis, when they yielded in 100 parts:

Composition Of Clover-Roots, No. 1, (From Brow Of Hill).

Moisture 4.34 Organic matter* 26.53 Mineral matter 69.13 ------- 100.00 ======= * Containing nitrogen .816 Equal to ammonia .991

"According to these data, an acre of land will yield three tons 12 cwts.

of nearly dry clover-roots, and in this quant.i.ty there will be about 66 lbs. of nitrogen. The whole of the soil from which the roots have been picked out, was pa.s.sed through a half-inch sieve. The stones left in the sieve weighed 141 lbs.; the soil which pa.s.sed through weighing 218 lbs.

"The soil was next dried by artificial heat, when the 218 lbs. became reduced to 185.487 lbs.

"In this partially dried state it contained:

Moisture 4.21 Organic matter* 9.78 Mineral matter 86.01 ------- 100.00 ======= * Containing nitrogen .391 Equal to ammonia .475 Including phosphoric acid .264

"I also determined the phosphoric acid in the ash of the clover-roots.

Calculated for the roots in a nearly dry state, the phosphoric acid amounts to .287 per cent.

"An acre of soil, according to the data, furnished by the six inches on the spot where the clover was thin, produced the following quant.i.ty of nitrogen:

Ton. Cwts. Lbs.

In the fine soil 1 11 33 In the clover-roots 0 0 66 -- -- -- Total quant.i.ty of nitrogen per acre 1 11 99 == == ==

"The organic matter in an acre of this soil, which can not be picked out by hand, it will be seen, contains an enormous quant.i.ty of nitrogen; and although, probably, the greater part of the roots and other remains from the clover-crop may not be decomposed so thoroughly as to yield nitrogenous food to the succeeding wheat-crop, it can scarcely be doubted that a considerable quant.i.ty of nitrogen will become available by the time the wheat is sown, and that one of the chief reasons why clover benefits the succeeding wheat-crop, is to be found in the abundant supply of available nitrogenous food furnished by the decaying clover-roots and leaves.

CLOVER-SOIL NO. 2, FROM THE BOTTOM OF THE HILL. (GOOD CLOVER.)

"A square yard of the soil from the bottom of the hill, where the clover was stronger than on the brow of the hill, produced 2 lbs. 8 oz. of fresh clover-roots; or 1 lb. 11 oz. 47 grains of partially dried roots; 61 lbs. 9 oz. of limestones, and 239.96 lbs. of nearly dry soil.

"The partially dried roots contained:

Moisture 5.06 Organic matter* 31.94 Mineral matter 63.00 ------- 100.00 ======= * Containing nitrogen .804

"An acre of this soil, six inches deep, produced 3 tons, 7 cwts. 65 lbs.

of clover-roots, containing 61 lbs. of nitrogen; that is, there was very nearly the same quant.i.ty of roots and nitrogen in them, as that furnished in the soil from the brow of the hill.

"The roots, moreover, yielded .365 per cent of phosphoric acid; or, calculated per acre, 27 lbs.

"In the partially dried soil, I found:

Moisture 4.70 Organic matter* 10.87 Mineral matter 84.43 ------- 100.00 ======= * Containing nitrogen .405 Equal to ammonia .491 Including phosphoric acid .321

"According to these determinations, an acre of soil from the bottom of the hill, contains:

Tons Cwts. Lbs.

Nitrogen in the organic matter of the soil 2 2 0 Nitrogen in clover-roots of the soil 0 0 61 --- --- --- Total amount of nitrogen per acre 2 2 61 === === ===

"Compared with the amount of nitrogen in the soil from the brow of the hill, about 11 cwt. more nitrogen was obtained in the soil and roots from the bottom of the hill, where the clover was more luxuriant.

"The increased amount of nitrogen occurred in fine root-fibres and other organic matters of the soil, and not in the coa.r.s.er bits of roots which were picked out by the hand. It may be a.s.sumed that the finer particles of organic matter are more readily decomposed than the coa.r.s.er roots; and as there was a larger amount of nitrogen in this than in the preceding soil, it may be expected that the land at the bottom of the hill, after removal of the clover, was in a better agricultural condition for wheat, than that on the brow of the hill."

CHAPTER XXVI.

EXPERIMENTS ON CLOVER-SOILS FROM BURCOTT LODGE FARM, LEIGHTON BUZZARD.

"The soils for the next experiments, were kindly supplied to me, in 1866, by Robert Valentine, of Burcott Lodge, who also sent me some notes respecting the growth and yield of clover-hay and seed on this soil.

"Foreign seed, at the rate of 12 lbs. per acre, was sown with a crop of wheat, which yielded five quarters per acre the previous year.

"The first crop of clover was cut down on the 25th of June, 1866, and carried on June 30th. The weather was very warm, from the time of cutting until the clover was carted, the thermometer standing at 80 Fahr. every day. The clover was turned in the swath, on the second day after it was cut; on the fourth day, it was turned over and put into small heaps of about 10 lbs. each; and on the fifth day, these were collected into larger c.o.c.ks, and then stacked.

"The best part of an 11-acre field, produced nearly three tons of clover-hay, sun-dried, per acre; the whole field yielding on an average, 2 tons per acre. This result was obtained by weighing the stack three months after the clover was carted. The second crop was cut on the 21st of August, and carried on the 27th, the weight being nearly 30 cwt. of hay per acre. Thus the two cuttings produced just about four tons of clover-hay per acre.

"The 11 acres were divided into two parts. About one-half was mown for hay a second time, and the other part left for seed. The produce of the second half of the 11-acre field, was cut on the 8th of October, and carried on the 10th. It yielded in round numbers, 3 cwt. of clover-seed per acre, the season being very unfavorable for clover-seed. The second crop of clover, mown for hay, was rather too ripe, and just beginning to show seed.

"A square foot of soil, 18 inches deep, was dug from the second portion of the land which produced the clover-hay and clover-seed.

SOIL FROM PART OF 11-ACRE FIELD TWICE MOWN FOR HAY.