Chapter XXVI: The Rothamsted Experiments (1)

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Reference has been so repeatedly made in the preceding pages to the Rothamsted experiments on manures, that it may form a fitting conclusion to the present treatise to give a short account of these famous experiments.

In describing these experiments, the author has remarked elsewhere[256] "that, in respect of their wide scope, dealing as they have done with almost every department of farming, the elaborate care and accuracy with which they have been carried out, the length of time they have been in progress, and, lastly, in respect of the important bearing their results have had on agricultural practice, these famous experiments may be justly described as unrivalled by any other similar ones."

Started on a small scale in 1837 by Sir John (then Mr) Lawes, they were placed on a systematic basis in 1843, in which year Sir John Lawes associated with himself Sir (then Dr) J. Henry Gilbert. They have thus been in progress for a period of fifty years--a fact which was celebrated a few months ago by the presentation of numerous congratulatory addresses from various learned and agricultural societies to the distinguished investigators, and the erection of a memorial granite slab at Rothamsted. What increases the feeling of gratitude due to Sir John Lawes by the agricultural community, is the fact that the entire expense of conducting these experiments has been borne by himself, and he has further most generously handed over to the nation a large sum of money and a certain area of land for carrying them on in perpetuity.

_Nature of Experiments on Crops and Manures._

The earliest systematic experiments were on turnips, and since then almost every common crop has been experimented on. Table I. (p. 562) is a list of the different experiments, with their duration, area, and number of plots.

_Soil of Rothamsted._

Before describing the more striking results of these experiments, it may be advisable to say that the elevation of the land at Rothamsted is about 400 feet above sea-level; that the average rainfall is about 28 inches per annum; and that the surface-soil is a heavy loam, and the subsoil a stiff clay, resting on chalk.

TABLE I.--LIST OF ROTHAMSTED FIELD EXPERIMENTS.

----------------------------------+------------+----------+------------ Crops. | Duration. | Area. | Plots. ----------------------------------+------------+----------+------------ | Years. | Acres. | Wheat (various manures) | 50 | 11 | 34 (or 37) Wheat alternated with fallow | 42 | 1 | 2 Wheat (varieties) | 15 | 4-8 | about 20 Barley (various manures) | 42 | 4-1/4 | 29 Oats (various manures) | 10[1] | 0-3/4 | 6 Beans (various manures) | 32[2] | 1-1/4 | 10 Beans (various manures) | 27[3] | 1 | 5 Beans, alternated with wheat | 28[4] | 1 | 10 Clover (various manures) | 29[5] | 3 | 18 Various leguminous plants | 16 | 3 | 18 | | | Turnips (various manures) | 28[6] | 8 | 40 Sugar-beet (various manures) | 5 | 8 | 41 Mangel-wurzel (various manures) | 18 | 8 | 41 +------------+ | Total root crops | 51 | | +------------+ | | | | Potatoes (various manures) | 18 | 2 | 10 Rotation (various manures) | 46 | 3 | 12 Permanent grass (various manures) | 38 | 7 | 22 ----------------------------------+------------+----------+------------ 1. Including one year fallow.

2. Including one year wheat and five years fallow.

3. Including four years fallow.

4. Including two years fallow.

5. Clover, twelve times sown (first in 1848), eight yielding crops, but
four of these very small, one year wheat, five years barley, twelve
years fallow.

6. Including barley without manure three years (eleventh, twelfth, and
thirteenth seasons).

WHEAT EXPERIMENTS.

The first experiments we shall refer to are those on _wheat_, since they are among the oldest, and their results the most striking of any.

_Unmanured Plots._

Wheat has been continuously grown year after year on three plots for fifty years, without the application of any manure whatever.

We shall first give the results of the first eight years as illustrating the effect of season, which accounts for the irregular results obtained. But for the difference in seasons, we should expect to find a steady decrease in the amount of produce; and this is shown in taking the average of groups of years, as we shall do in the next table.

WHEAT GROWN CONTINUOUSLY ON SAME LAND (unmanured).

TABLE II.--(a.) _Remits of first Eight Years (1844 to 1851)._

Year. Bushels. | Year. Bushels. 1844 15 | 1849. 19-1/4 1845 23-1/4 | 1850. 15-7/8 1846 18 | 1851. 15-7/8 1847 16-7/8 | ------ 1848 14-3/4 | Average of 8 years 17-3/8 | ------

TABLE III.--(b.) _Results of subsequent Forty Years (1852 to 1891)._

Grain Weight per Straw (bushels). bushel. (cwts.) 20 years (1852-1871) 14-1/2 57-5/8 13 20 " (1872-1891) 11-1/2 58-3/4 8-5/8 40 " (1852-1891) 13 58-1/4 10-5/8 49th season (1891) 9-3/8 59-1/2 7-1/2

It is interesting to notice the comparatively slight decrease which has taken place in the yield of wheat during these fifty years. With such wide variations, due to season, it is extremely difficult, as Sir J. Henry Gilbert has pointed out, to estimate rate of decline due to exhaustion. Excluding the very bad seasons, this may be reckoned at from one-fourth to one-third of a bushel per acre per annum. _The return of the first year is 15 bushels, while the yield of the forty-ninth season is 9-3/8 bushels._ The average of the returns obtained during these fifty years is really in _excess of the average yield of the principal wheat-producing countries in the world_. This is truly a most astounding result.

The next experiments we shall describe are those on the influence of farmyard manure on the wheat crop when grown continuously.

TABLE IV.--WHEAT GROWN CONTINUOUSLY WITH FARMYARD MANURE (14 tons per annum).

Weight per Bushels. bushel Straw (lb.) (cwts.) 8 years (1844-1852) 28 - - 20 " (1852-1871) 35-7/8 60 33-7/8 20 " (1872-1891) 33-1/2 60-3/8 31-3/8 40 " (1852-1891) 34-7/8 60-1/4 32-5/8

It will be seen from the above results, which contain merely a selection from a very much greater number of experiments, that farmyard manure gives as good an average over the forty years as most of the artificial mixtures do. That this is due to the nitrogen it contains, is strikingly illustrated by the fact that mixed mineral manures alone give less than half the return, and also by the fact that ammonia salts alone give a return twice as great as mineral mixtures; while, lastly, the mixture of mineral manures and ammonia salts gives but a slight increase over that obtained with ammonia salts alone.

The remaining results, selected from a much larger number, need no comment, and we shall give them in tabular form.

Table V.--WHEAT GROWN CONTINUOUSLY WITH ARTIFICIAL MANURES, FARMYARD MANURE, AND UNMANURED.

_Average of Forty Years (1852-91)._

-------------------------------------+--------------------------------------+
| PRODUCE PER ACRE--AVERAGE PER ANNUM. |
+--------------------------------------+
| Dressed grain. |
MANURES PER ACRE PER ANNUM. +--------------------------------------+
| Quantity. |
+------------+------------+------------+
| 20 years, | 20 years, | 40 years, |
| 1852-71. | 1872-91. | 1852-91. |
-------------------------------------+------------+------------+------------+
| bush. | bush. | bush. |
Farmyard manure, 14 tons per annum | | | |
since 1843 | 35-7/8 | 33-1/2 | 34-7/8 |
Unmanured continuously | 14-1/2 | 11-1/2 | 13 |
Mixed mineral manures[1] and 3-1/2 | | | |
cwt. superphosphate | 17 | 12-7/8 | 15 |
Mixed mineral manures, 3-1/2 cwt. | | | |
superphosphate, 200 lb. ammonium | | | |
salts | 26-1/2 | 21-3/4 | 24-1/8 |
Mixed mineral manures and 3-1/2 cwt. | | | |
superphosphate, 600 lb. ammonium | | | |
salts | 38-1/4 | 34-3/4 | 36-1/2 |
Mixed mineral manures, 3-1/2 cwt. | | | |
superphosphate, 275 lb. nitrate | | | |
of soda | 36-7/8 | 34 | 35-3/8 |
275 lb. nitrate of soda | 26 | 19-3/8 | 22-3/4 |
400 lb. ammonium salts every year | | | |
since 1845 | 22-1/2 | 19 | 22-1/2 |
400 lb. ammonium salts, 3-1/2 cwt. | | | |
superphosphate | 28 | 22-1/4 | 25-1/8 |
Mineral manure, 3-1/2 cwt. | | | |
superphosphate, 400 lb. ammonium | | | |
salts in autumn | 31-5/8 | 29-1/2 | 30-1/2 |
-------------------------------------+------------+------------+------------+
----------------------------------------------------------------------------+
| PRODUCE PER ACRE--AVERAGE PER ANNUM. |
+--------------------------------------+
| Dressed grain. |
MANURES PER ACRE PER ANNUM. +--------------------------------------+
| Quantity. |
+------------+------------+------------+
| 20 years, | 20 years, | 40 years |
| 1852-71. | 1872-91. | 1852-91. |
-------------------------------------+------------+------------+------------+
| lb. | lb. | lb. |
Farmyard manure, 14 tons per annum | | | |
since 1843 | 60 | 60-3/8 | 60-1/4 |
Unmanured continuously | 57-5/8 | 58-3/4 | 58-1/4 |
Mixed mineral manures and 3-1/2 | | | |
cwt. superphosphate | 58-7/8 | 59 | 58-7/8 |
Mixed mineral manures, 3-1/2 cwt. | | | |
superphosphate, 200 lb. ammonium | | | |
salts | 59-3/8 | 60 | 59-5/8 |
Mixed mineral manures and 3-1/2 cwt. | | | |
superphosphate, 600 lb. ammonium | | | |
salts | 59 | 60 | 59-1/2 |
Mixed mineral manures, 3-1/2 cwt. | | | |
superphosphate, 275 lb. nitrate of | | | |
soda | 58-3/8 | 59-5/8 | 59 |
275 lb. nitrate of soda | 56-5/8 | 56-5/8 | 56-5/8 |
400 lb. ammonium salts every year | | | |
since 1845 | 58 | 57-3/8 | 57-5/8 |
400 lb. ammonium salts, 3-1/2 cwt. | | | |
superphosphate | 57-3/8 | 58 | 57-5/8 |
Mineral manure, 3-1/2 cwt. | | | |
superphosphate, 400 lb. ammonium | | | |
salts in autumn | 59-1/2 | 60 | 59-3/4 |
-------------------------------------+------------+------------+------------+
-------------------------------------+--------------------------------------
| PRODUCE PER ACRE--AVERAGE PER ANNUM.
+--------------------------------------
MANURES PER ACRE PER ANNUM. | Total straw.
+--------------------------------------
| 20 years, | 20 years, | 40 years
| 1852-71. | 1872-91. | 1852-91.
-------------------------------------+------------+------------+------------
| cwt. | cwt. | cwt.
Farmyard manure, 14 tons per annum | | |
since 1843 | 33-7/8 | 31-3/8 | 32-5/8
Unmanured continuously | 13 | 8-5/8 | 10-5/8
Mixed mineral manures and 3-1/2 | | |
cwt. superphosphate | 15 | 9-3/4 | 12-3/8
Mixed mineral manures, 3-1/2 cwt. | | |
superphosphate, 200 lb. ammonium | | |
salts | 24-1/2 | 19-1/8 | 21-7/8
Mixed mineral manures and 3-1/2 cwt. | | |
superphosphate, 600 lb. ammonium | | |
salts | 41-3/8 | 39-5/8 | 40-1/2
Mixed mineral manures, 3-1/2 cwt. | | |
superphosphate, 275 lb. nitrate of | | |
soda | 41-1/2 | 37-3/4 | 39-5/8
275 lb. nitrate of soda | 28-1/4 | 18-1/2 | 23-3/8
400 lb. ammonium salts every year | | |
since 1845 | 24-3/4 | 16-1/4 | 20-1/2
400 lb. ammonium salts, 3-1/2 cwt. | | |
superphosphate | 26-3/8 | 21 | 23-3/4
Mineral manure, 3-1/2 cwt. | | |
superphosphate, 400 lb. ammonium | | |
salts in autumn | 31-1/4 | 28-3/8 | 29-3/4
-------------------------------------+------------+------------+------------
1. By the term mixed mineral manures is meant a mixture of mineral
fertilisers, not including phosphates.

Table VI.--EXPERIMENTS ON THE GROWTH OF BARLEY FOR FORTY YEARS, 1852-91.

----------------------------------------------------------------------------+
| PRODUCE PER ACRE--AVERAGE PER ANNUM. |
+--------------------------------------+
| Dressed grain. |
MANURES PER ACRE PER ANNUM. +--------------------------------------+
| Quantity. |
+------------+------------+------------+
| 20 years, | 20 years, | 40 years |
| 1852-71. | 1872-91. | 1852-91. |
-------------------------------------+------------+------------+------------+
| lb. | lb. | lb. |
Unmanured continuously | 52-3/8 | 51-3/4 | 52 |
3-1/2 cwt. superphosphate of lime | 53-1/4 | 53 | 53-1/8 |
Mixed mineral manures | 53 | 51-7/8 | 52-1/2 |
Mixed mineral manures, 3-1/2 cwt. | | | |
superphosphate | 53-3/8 | 52-3/8 | 53 |
200 lb. ammonium salts | 52-1/8 | 52 | 52 |
200 lb. ammonium salts, 3-1/2 cwt. | | | |
superphosphate | 53-3/8 | 52-1/4 | 52-7/8 |
200 lb. ammonium salts, | | | |
mixed mineral manures | 52-3/4 | 52-1/2 | 52-5/8 |
Manures, 3-1/2 cwt. | | | |
superphosphate of lime | 54 | 54-1/8 | 54 |
275 lb. nitrate of soda | 52 | 52-1/8 | 52 |
275 lb. nitrate of soda, 3-1/2 cwt. | | | |
superphosphate | 53-3/8 | 53-1/4 | 53-1/4 |
275 lb. nitrate of soda, | | | |
mixed mineral manures. | 52-1/4 | 52-3/4 | 52-1/2 |
275 lb. nitrate of soda, | | | |
mixed mineral manures, | | | |
3-1/2 cwt. superphosphate | 53-3/8 | 54 | 53-5/8 |
1000 lb. rape-cake | 53-3/4 | 53-7/8 | 53-7/8 |
1000 lb. rape-cake, 3-1/2 cwt. | | | |
superphosphate | 53-7/8 | 54-3/8 | 54-1/8 |
1000 lb. rape-cake, | | | |
mixed mineral manures | 53-3/4 | 54-1/8 | 54 |
1000 lb. rape-cake, | | | |
mixed mineral manures, and | | | |
3-1/2 cwt. superphosphate | 53-5/8 | 54-1/4 | 53-7/8 |
Farmyard manure, 14 tons every year | 54-3/8 | 54-1/4 | 54-1/4 |
-------------------------------------+------------+------------+------------+

-------------------------------------+-------------------------------------- | PRODUCE PER ACRE--AVERAGE PER ANNUM. +-------------------------------------- MANURES PER ACRE PER ANNUM. | Total straw. +-------------------------------------- | 20 years, | 20 years, | 40 years | 1852-71. | 1872-91. | 1852-91. -------------------------------------+------------+------------+------------ | cwt. | cwt. | cwt. Unmanured continuously | 11-3/4 | 6-7/8 | 9-3/8 3-1/2 cwt. superphosphate of lime | 13-3/8 | 8-1/4 | 10-3/4 Mixed mineral manures | 12-1/4 | 7 | 9-5/8 Mixed mineral manures, 3-1/2 cwt. | | | superphosphate | 14-3/8 | 8-3/8 | 11-3/8 200 lb. ammonium salts | 18-1/2 | 13-1/2 | 16 200 lb. ammonium salts, 3-1/2 cwt. | | | superphosphate | 27-5/8 | 20-1/8 | 23-7/8 200 lb. ammonium salts, | | | mixed mineral manures | 20-1/4 | 15-1/8 | 18 Manures, 3-1/2 cwt. | | | superphosphate of lime | 28-1/2 | 23-3/8 | 25-7/8 275 lb. nitrate of soda | 22-1/8 | 15-7/8 | 19 275 lb. nitrate of soda, 3-1/2 cwt. | | | superphosphate | 30-1/2 | 23-3/8 | 27 275 lb. nitrate of soda, | | | mixed mineral manures. | 23-7/8 | 17-1/2 | 20-3/4 275 lb. nitrate of soda, | | | mixed mineral manures, | | | 3-1/2 cwt. superphosphate | 32-3/8 | 24-1/2 | 28-1/2 1000 lb. rape-cake | 26-7/8 | 20 | 23-3/8 1000 lb. rape-cake, 3-1/2 cwt. | | | superphosphate | 28-3/8 | 21-1/2 | 24-7/8 1000 lb. rape-cake, | | | mixed mineral manures | 27-1/8 | 19-7/8 | 23-1/2 1000 lb. rape-cake, | | | mixed mineral manures, and | | | 3-1/2 cwt. superphosphate | 29-3/4 | 21-7/8 | 25-5/8 Farmyard manure, 14 tons every year | 28-1/4 | 29-3/4 | 29 -------------------------------------+------------+------------+------------

TABLE VII.

EXPERIMENTS ON THE GROWTH OF OATS, 1869-78.

-------------------------------------------+----------------------------
| AVERAGE PER ANNUM.
| 5 YEARS, 1869-73.
+----------------------------
MANURES PER ACRE PER ANNUM. | Dressed grain. |
+----------+--------+ Total
| Quantity.| Weight | straw.
| | per |
| | bushel.|
-------------------------------------------+----------+--------+--------
| Bushels. | lb. | cwt.
Unmanured | 19-7/8 | 33-3/4 | 10-3/8
200 lb. sulphate potash, 100 lb. sulphate | | |
soda, 100 lb. sulphate magnesia, and | | |
3-1/2 cwt. superphosphate of lime | 24-1/2 | 35 | 13-3/8
400 lb. ammonium salts | 47 | 35-7/8 | 28-1/2
400 lb. ammonium salts, 200 lb. sulphate | | |
potash, 100 lb. sulphate soda, 100 lb. | | |
sulphate magnesia, and 3-1/2 cwt. | | |
superphosphate | 59 | 37 | 41-1/8
550 lb. nitrate of soda | 47-1/8 | 35-1/2 | 27-1/2
550 lb. nitrate of soda, 200 lb. sulphate | | |
potash, 100 lb. sulphate soda, 100 lb. | | |
sulphate magnesia, and 3-1/2 cwt. | | |
superphosphate | 57-1/2 | 35-3/4 | 35
-------------------------------------------+----------+--------+--------
| AVERAGE PER ANNUM.
| 4 YEARS, 1874-78.
-------------------------------------------+----------------------------
| Bushels. | lb. | cwt.
Unmanured | 13-3/4 | 31-1/4 | 6
200 lb. sulphate potash, 100 lb. sulphate | | |
soda, 100 lb. sulphate magnesia, and | | |
3-1/2 cwt. superphosphate of lime | 13-1/8 | 31-5/8 | 6-1/8
200 lb. ammonium salts. | 28-7/8 | 33-1/4 | 14-1/8
200 lb. ammonium salts, 200 lb. sulphate | | |
potash, 100 lb. sulphate soda, 100 lb. | | |
sulphate magnesia, and 3-1/2 cwt. | | |
superphosphate | 38 | 35-1/2 | 20
275 lb. nitrate of soda | 26-3/8 | 31-5/8 | 11-1/8
275 lb. nitrate of soda, 200 lb. sulphate | | |
potash, 100 lb. sulphate soda, 100 lb. | | |
sulphate magnesia, and 3-1/2 cwt. | | |
superphosphate | 28-1/2 | 34-1/8 | 14
-------------------------------------------+----------+--------+--------

TABLE VIII.--EXPERIMENTS ON ROOT CROPS: SWEDISH TURNIPS.
_Fifteen Seasons_, 1856-70.[1] Roots and Leaves carted off the Land.
-----+--------------------------------------------+---------------------+
| | SERIES 1. |
| | |
| | Standard manures |
| | only. |
| | |
| | |
| | |
| | |
| | |
| | |
PLOT.| STANDARD MANURES. | |
-----+--------------------------------------------+---------------------+
| | Roots. | Leaves. |
| |----------+----------+
| |Tons. cwt.|Tons. cwt.|
1 |Farmyard manure, 14 tons | 6 4 | 0 17 |
2 |Farmyard manure, 14 tons, and superphosphate| 6 7 | 0 16 |
3 |Without manure, 1846, and since | 0 11 | 0 3 |
4 |Superphosphate, each year; sulphate potash, | | |
| soda, and magnesia, 1856-60 | 2 16 | 0 8 |
5 |Superphosphate, each year | 2 12 | 0 9 |
6 |Superphosphate, each year; sulphate potash, | | |
| 1856-60 | 2 7 | 0 7 |
7 |Superphosphate, each year; sulphate, potash,| | |
| and 36-1/2 lb. ammonium salts, 1856-60 | 2 12 | 0 7 |
8 |Unmanured 1853, and since; previously part | | |
| unmanured; part superphosphate | 1 3 | 0 4 |
-----+--------------------------------------------+----------+----------+

_Note._--Sulphate of ammonia is estimated to contain 23 per cent ammonia, and muriate of ammonia 27 per cent. Ammonium salts, in each case, equal parts sulphate and muriate of ammonia of commerce; and the mixture is estimated to contain 25 per cent ammonia. The 328 lb. nitric acid (sp. gr. 1.35) mixed with sawdust, and used as a cross-dressing on the plots of Series 2 from 1856-60, were estimated to contain nitrogen = 50 lb. ammonia.

1. The crops of 1859 and 1860 failed, and were ploughed in; but as the manures were applied, and there would be accumulation with the soil for the succeeding crops, the average produce is calculated as for fifteen years--that is, the produce of the thirteen years is, in each case, divided by 15.

-----+-----------------------+-----------------------
| SERIES 2. | SERIES 3.
| |
| Standard manures, | Standard manures,
| and cross-dressed | and cross-dressed
| with-- | with--
| |
|5 years, 1856-60, |5 years, 1856-60,
|3000 lb. sawdust, and |200 lb. ammonium
|328 lb. nitric acid. |salts
| |
|10 years, 1861-70, |10 years, 1861-70,
|550 lb. nitrate soda. |400 lb. ammonium salts.
PLOT.| |
-----+-----------+-----------+-----------+-----------
| Roots. | Leaves. | Roots. | Leaves.
+-----------+-----------+-----------+-----------
|Tons. cwt.|Tons. cwt.|Tons. cwt.|Tons. cwt.
1 | 7 9 | 1 2 |8 8 | 1 4
2 | 7 13 | 1 3 |8 5 | 1 5
3 | 0 19 | 0 4 |0 13 | 0 3
4 | 5 2 | 0 16 |4 12 | 0 14
| | | |
5 | 4 13 | 0 18 |3 16 | 0 15
6 | 4 11 | 0 14 |4 5 | 0 13
| | | |
7 | 4 13 | 0 14 |4 12 | 0 14
| | | |
8 | 1 13 | 0 5 |1 2 | 0 5
| | | |
-----+-----------+-----------+-----------+-----------

-----+-----------------------+-----------------------
| SERIES 4. | SERIES 5.
| |
| Standard manures, | Standard manures,
| and cross-dressed | and cross-dressed
| with-- | with--
| |
|5 years, 1856-60, |5 years, 1856-60,
|200 lb. ammonium salts,|3000 lb. sawdust.
|and 3000 lb. sawdust. |
| |10 years, 1861-70,
|10 years, 1861-70, |2000 lb. rape-cake.
|400 lb. ammonium salts,|
PLOT.|and 2000 lb. rape-cake.|
-----+-----------+-----------+-----------+-----------
| Roots. | Leaves. | Roots. | Leaves.
+-----------+-----------+-----------+-----------
|Tons. cwt.|Tons. cwt.|Tons. cwt.|Tons. cwt.
1 | 8 16 | 1 9 | 8 0 | 1 4
2 | 8 14 | 1 9 | 7 16 | 1 2
3 | 3 6 | 0 14 | 3 8 | 0 13
4 | 6 12 | 1 5 | 5 8 | 0 17
| | | |
5 | 5 16 | 1 7 | 5 0 | 0 19
6 | 6 6 | 1 2 | 5 3 | 0 16
| | | |
7 | 6 15 | 1 4 | 5 9 | 0 17
| | | |
8 | 3 19 | 0 18 | 3 14 | 0 19
| | | |
-----+-----------+-----------+-----------+-----------

TABLE IX.--EXPERIMENTS ON MANGEL-WURZEL.

_Average of Sixteen Seasons_, 1876-92. Manures per Acre per Annum.

-----+--------------------------------------------+---------------------
| | SERIES 1.
| |
| | Standard manures
| | only.
| |
| |
PLOT.| STANDARD MANURES. |
-----+--------------------------------------------+----------+----------
| | Roots. | Leaves.
| |----------+----------
| |Tons. cwt.|Tons. cwt.
1 |Farmyard manure, 14 tons | 16 6 | 2 17
2 |Farmyard manure, 14 tons, and 3-1/2 cwt. | |
| superphosphate | 16 12 | 2 18
3 |Without manure, 1846, and since | 4 9 | 1 8
4 |3-1/2 cwt. superphosphate, 500 lb. sulphate | |
| of potash and 400 lb. mixed mineral manure| 5 8 | 1 1
5 |3-1/2 cwt. superphosphate | 5 0 | 1 1
6 |3-1/2 cwt. superphosphate, and 500 lb. | |
| sulphate of potash | 4 9 | 0 18
7 |3-1/2 cwt. superphosphate, 500 lb. sulphate | |
| of potash, and 36-1/2 lb. ammonium salts | 5 17 | 1 8
-----+--------------------------------------------+----------+----------

-----+-----------------------+-----------------------+
| SERIES 2. | SERIES 3. |
| | |
|Standard manures, |Standard manures, |
|and cross-dressed |and cross-dressed |
|with 550 lb. |with 400 lb. |
|nitrate of soda. |ammonium salts. |
PLOT.| | |
-----+-----------+-----------+-----------+-----------+
| Roots. | Leaves. | Roots. | Leaves. |
+-----------+-----------+-----------+-----------+
|Tons. cwt.|Tons. cwt.|Tons. cwt.|Tons. cwt.|
1 | 22 11 | 4 2 | 22 3 | 5 7 |
2 | 23 12 | 4 14 | 21 8 | 5 6 |
| | | | |
3 | 13 7 | 3 4 | 6 14 | 2 18 |
4 | 12 17 | 3 15 | 16 2 | 3 0 |
| | | | |
5 | 15 13 | 3 5 | 8 10 | 3 1 |
6 | 15 15 | 2 18 | 14 6 | 2 16 |
| | | | |
7 | 16 0 | 3 1 | 16 3 | 3 0 |
| | | | |
-----+-----------+-----------+-----------+-----------+

-----+-----------------------+-----------------------
| SERIES 4. | SERIES 5.
| |
|Standard manures, |Standard manures,
|and cross-dressed |and cross-dressed with
|with 2000 lb. rape |2000 lb. rape-cake.
|cake, and 400 lb. |
PLOT.|ammonium salts. |
-----+-----------+-----------+-----------+-----------
| Roots. | Leaves. | Roots. | Leaves.
+-----------+-----------+-----------+-----------
|Tons. cwt.|Tons. cwt.|Tons. cwt.|Tons. cwt.
1 | 24 11 | 6 1 | 23 7 | 4 6
2 | 23 12 | 6 1 | 23 1 | 4 6
| | | |
3 | 10 11 | 3 17 | 11 2 | 3 0
4 | 24 18 | 5 7 | 20 4 | 3 9
| | | |
5 | 11 7 | 4 2 | 12 3 | 3 2
6 | 21 6 | 5 7 | 16 14 | 2 15
| | | |
7 | 21 6 | 5 9 | 17 10 | 3 3
| | | |
-----+-----------+-----------+-----------+-----------

TABLE X.--Experiments with different Manures on Permanent Meadow-land.

_Thirty-six Years_, 1856-91.

-------------------------------+--------------------------+--------------------
| Produce per Acre, weighed as Hay.
+--------------------------+--------------------
| Average per Annum, | Average per annum,
| 20 years, 1856-75 | 16 years, 1876-91
| (1st crops only). | (1st and 2d crops).
Manures per Acre per Annum. +--------+--------+--------+------+------+------
|10 years|10 years|20 years| 1st | 2d |
|1856-65.|1866-75.|1856-75.|crops.|crops.|Total.
-------------------------------+--------+--------+--------+------+------+------
| cwt. | cwt. | cwt. | cwt. | cwt. | cwt.
Unmanured continuously | 22-1/2 | 20 | 21-1/4 |18 | 8-1/2|26-1/2
3-1/2 cwt. superphosphate of | | | | | |
lime | 23-1/4 | 21-1/4 | 22-1/4 |18 | 9 |27-1/2
3-1/2 cwt. superphosphate of | | | | | |
lime, and 400 lb. ammonium | | | | | |
salts | 33-7/8 | 30-1/2 | 32-1/4 |30-3/4|10-1/2|41-1/4
400 lb. ammonium salts | 30-1/2 | 22 | 26-1/4 |18-1/4|10-1/8|27-3/8
275 lb. nitrate of soda, 3-1/2 | | | | | |
cwt. superphosphate, and | | | | | |
mixed mineral manure | 45-1/4 | 47-5/8 | 46-1/2 |41-1/8|12-1/8|53-1/4
275 lb. nitrate of soda | 34-1/4 | 33-1/2 | 33-7/8 |30-1/8|10 |40-1/8
-------------------------------+--------+--------+--------+------+------+------

TABLE XI.--EXPERIMENTS ON THE GROWTH OF POTATOES.

_Average of Five Seasons, 1876-80._[1]
----+-------------------------------+-------------------------------------------
| | PRODUCE PER ACRE--TUBERS.
Plot| MANURE PER ACRE PER ANNUM. |----------+----------+----------+----------
| | Good. | Small. | Diseased.| Total.
----+-------------------------------|----------+----------+----------+----------
Plot| |Tons cwt. |Tons cwt. |Tons cwt. |Tons cwt.
1 |Unmanured | 1 18 | 0 6-1/4| 0 2-1/4| 2 6-1/2
2 |Farmyard manure (14 tons) | 3 19-3/8| 0 7-5/8| 0 6-5/8| 4 13-5/8
3 |Farmyard manure (14 tons), and | | | |
| 3-1/2 cwt. superphosphate | 4 9-1/2| 0 8 | 0 8-3/4| 5 6-1/4
4 |Farmyard manure (14 tons), | | | |
| 3-1/2 cwt. superphosphate, | | | |
| and 550 lb. nitrate of soda | 5 8 | 0 7 | 0 19-1/2| 6 14-1/2
5 |400 lb. ammonium salts | 1 19-1/2| 0 7-1/8| 0 3-1/2| 2 10-1/8
6 |550 lb. nitrate of soda | 2 11-7/8| 0 6-7/8| 0 5-1/4| 3 4
7 |400 lb. ammonium salts, 3-1/2 | | | |
| cwt. superphosphate, 300 lb. | | | |
| sulphate potash, 100 lb. | | | |
| sulphate soda, 100 lb. | | | |
| sulphate magnesia | 5 14-1/4| 0 8-1/4| 0 14-3/4| 6 17-1/4
8 |550 lb. nitrate of soda, 3-1/2 | | | |
| cwt. superphosphate, 300 lb. | | | |
| sulphate potash, 100 lb. | | | |
| sulphate soda, 100 lb. | | | |
| sulphate magnesia | 5 19-7/8| 0 7-7/8| 0 19-1/8| 7 6-7/8
9 |3-1/2 cwt. superphosphate | 3 0-3/4 | 0 8 | 0 4-5/8| 3 13-3/8
10 |3-1/2 cwt. superphosphate, 300 | | | |
| lb. sulphate potash, 100 lb. | | | |
| sulphate soda, and 100 lb. | | | |
| sulphate magnesia | 3 4-1/2 | 0 6-1/2| 0 4-7/8| 3 15-7/8
----+-------------------------------+----------+----------+----------+----------
1. In each year the tops were spread on the respective plots.

TABLE XII.--EXPERIMENTS ON THE GROWTH OF POTATOES--_Continued_.

_Average of Twelve Seasons, 1881-92._

----+------------------------------+-------------------------------------------
| | PRODUCE PER ACRE--TUBERS.
Plot| MANURE PER ACRE PER ANNUM. |----------+----------+----------+----------
| | Good. | Small. | Diseased.| Total.
----+------------------------------|----------+----------+----------+----------
| |Tons cwt. |Tons cwt. |Tons cwt. |Tons cwt.
1 |Unmanured in 1876, and each | | | |
| year since | 1 3-3/4| 0 3-3/4| 0 0-1/4| 1 7-3/4
2 |Unmanured in 1882, and since; | | | |
| previously farmyard manure | | | |
| (14 tons) | 2 14-1/4| 0 4-3/4| 0 2 | 3 1
3 |Farmyard manure (14 tons) | | | |
| alone, 1883, and since; | | | |
| previously 3-1/2 cwt. | | | |
| superphosphate also | 4 3-1/4| 0 4-1/4| 0 4-1/2| 4 12
4 |Farmyard manure (14 tons) | | | |
| alone, 1883, and since. In | | | |
| 1882 and previously 3-1/2 | | | |
| cwt. superphosphate, and in | | | |
| 1881 and previously 550 lb. | | | |
| nitrate of soda also | 4 6-1/4| 0 4-1/2| 0 4-3/4| 4 15-1/2
5 |400 lb. ammonium salts | 1 2-3/4| 0 4-3/4| 0 0-1/2| 1 8
6 |550 lb. nitrate of soda | 1 17-3/4| 0 3-3/4| 0 0-3/4| 2 2-1/4
7 |400 lb. ammonium salts, 3-1/2 | | | |
| cwt. superphosphate, 300 lb.| | | |
| sulphate of potash, and 200 | | | |
| lb. mixed mineral manure | 5 6-3/4| 0 5 | 0 4-1/2| 5 16-1/4
8 |550 lb. nitrate of soda, 3-1/2| | | |
| cwt. superphosphate, 300 lb.| | | |
| sulphate of potash, and 200 | | | |
| lb. mixed mineral manure | 5 7-1/2| 0 4-1/4| 0 3-3/4| 5 15-1/2
9 |3-1/2 cwt. superphosphate | 2 17-3/4| 0 3-1/4| 0 1 | 3 2
10 |3-1/2 cwt. superphosphate, 300| | | |
| lb. sulphate of potash, and | | | |
| 200 lb. mixed mineral manure| 3 2-1/4| 0 3-1/4| 0 1-1/4| 3 6-3/4
----+------------------------------+----------+----------+----------+----------

FOOTNOTES:

[256] See Sir John Bennet Lawes, Bart., and the Rothamsted Experiments. By C. M. Aikman. ('Scottish Farmer' Office, Glasgow.)

INDEX.

Abraum salts, 421.

Absorptive power of soils for water, 67, 98;
how to increase, 74.

Acidity in soils neutralised by lime, 458.

Acids fixed by soil, 58.

Adametz on organisms in soil, 92.

Adulteration of guano, 318-320.

Africa, guano from, 298, 328.

Agricultural chemistry, historical introduction to, 3-61;
Liebig's researches on, 23-32;
Liebig's services to, 31.

Agronomy, 56.

Air, ammonia in, 48, 118;
nitrates in, 118; nitrites in, 118;
nitrogen in, 116;
organic nitrogen in, 118.

Aitken, Dr, experiments with basic slag, 413
--with beans, 526, 530;
on germ-life in bones, 368;
on manuring of turnips, 515.

Albert, Heinrich, on solubility of basic slag, 409.

Albite, composition of, 103.

Albuminates, 460.

Albuminoids, in plants, 491;
of milk, nitrification in, 182;
phosphorus in, 205.

Algerian phosphate, 379.

Algoa Bay, guano deposits at, 328.

Alkalies, in cow-dung, 226, 227
--cow-urine, 230
--horse-dung, 226, 227
--horse-urine, 230
--pig-dung, 226, 227
--pig-urine, 230
--sheep-dung, 226, 227
--sheep-urine, 230.

Alkalinity necessary for nitrification, 172.

Alumina, in ash of plants, 55;
compounds, reversion caused by, 388, 400;
salts, in _salinas_, 335.

America, virgin soils of, 133.

American farming, 86.

Amides, 501.

Ammonia, absorbed by soil, 81;
amount dissolved in rain, 49;
amount in air, 48;
amount in soil, 127;
amount supplied to soil by rain, 155;
converted into nitrates in soil, 50;
converted into nitrous acid, 167;
fixed by soil, 58;
from decomposition of farmyard manure, 258;
from gas-works, 353;
lost in mixing manures, 533;
relation of, to plants, 48-50;
salts, most easily nitrifiable, 191;
salts of, in farmyard manure, 257;
sulphate of, 352-358;
value of, as a manure, 352.

Ammonium chloride in Chincha guano, 305.

Ammonium-magnesium phosphate in Chincha guano, 305.

Ammonium oxalate in concretionary nodules, 328.

Ammonium phosphate, in Chincha guano, 305;
in concretionary nodules, 328.

Ammonium sulphate, 352-358;
in Chincha guano, 305;
in concretionary nodules, 328.

Ammonium sulphocyanate, 355.

Ammonium urate in concretionary nodules, 328.

Amphibole, potash in, 220.

Analysis, of manures, 539-554;
of soils, value of, 90.

Anderson, Dr, analyses of minerals by, 103, 105-107;
on nitrogen in soil, 121, 124.

Angamos, guano from, 301, 329.

Animals, phosphoric acid in, 205;
potash in, 205;
solid excreta of, 224;
urine of, 228.

Apatite, Canadian, 201, 374;
composition of, 210;
most abundant form of phosphoric acid, 200;
varieties of, 200.

Application of manures, 474-492.

Arabian coast, guano deposits on, 328.

Arable soil, absorptive power of, 98.

Arbrohlos Island guano, 309.

Arendt, experiments on oats by, 503.

Aristotelian doctrine of chemical elements, 4.

Artificial soil, 54.

Aruba phosphate, 308, 328, 379.

Ash, constituents of plants, 53-55;
of rye, phosphoric acid in, 204;
of wheat, phosphoric acid in, 204;
of farmyard manure, composition of, 287, 288.

Ashes, an adulterant of guano, 319;
mixed with manures, 532.

Asia, guano from, 298.

Asparagin, nitrification in, 182.

Atacama, nitrate of soda deposits at, 342.

Atmosphere, ammonia in, 48, 81;
relation of, to plants, 39.

Atwater on nitrogen in plants, 44.

Augite, 105.

Australia, guano from, 298;
virgin soils of, 133.

Avenine in oats, 503.

Aves guano, 309, 328;
phosphoric acid in, 330.

Bacilli, 94.

Bacon, Lord, on salt as a manure, 469.

Bacteria, in soil, 92;
different classes of, 93-96.

Baker Island guano, 309, 328;
phosphoric acid in, 330.

Ballestas, guano from, 302, 327;
nitrogen in, 329;
phosphoric acid in, 329.

Barilla, potash in, 420.

Barley, farmyard manure not suited for, 497;
fertilising ingredients removed from soil by, 485;
manurial constituents in, 282;
manuring of, 495, 498;
nitrogen removed in crop of, 145;
Norfolk experiments on, 497;
period of growth of, 495;
period of ripening of, 495;
Rothamsted experiments on growth of, 566;
soils suited for, 496;
uniform manuring of, 497.

Barley soils, amount of nitrates and nitrogen in, 158.

Barley-straw, composition of, 238;
manurial constituents in, 282.

Basalt, phosphoric acid in, 202, 210.

Bases fixed by soil, 58.

Basic ammonium phosphate in concretionary nodules, 328.

Basic process of steel-smelting, 400.

Basic silicates, 103.

Basic slag, 401-417;
after-effects of, 412;
application of, method of, 416
--rate of, 414;
compared with other manures, 410-414;
composition of, 404, 417;
Darmstadt experiments with, 410;
discovery of value of, 403;
manufacture of, 401;
preparation of, processes for, 406;
relative activity of, 411;
soils best suited for, 414;
solubility of, 408;
Wagner's experiments with, 408-413.

Bat guano, 320, 325;
nitrogen in, 325;
phosphoric acid in, 325.

Beans, fertilising ingredients removed from soil by, 485;
good effect of gypsum on, 526;
manurial constituents in, 282;
manuring of, 525-527;
phosphorus in, 205;
relative value of manurial ingredients to, 526;
source of nitrogen, 153.

Bean-straw, manurial constituents in, 282.

Beatson, General, experiments of, with Peruvian guano, 301.

Beddington meadows, irrigation at, 432.

Bedfordshire, coprolites from, 374.

Belgian phosphate, 377.

Berthelot on sources of plant-nitrogen, 42.

Biological properties of soil, 92-96.

Blood corpuscles, potash in, 217.

Blood, dried, 424;
composition of, 424;
manure for sugar-cane, 425;
potash in, 217, 219;
rate of nitrification in, 192;
source of nitrogen, 152;
suited for horticulture, 425.

Bohemia, phosphoric acid removed from, 206.

Bolivia, guano deposits at, 327.

Bollaert on nitrate deposits, 333.

Bone-ash, 369;
composition of, 372.

Bone-black, 369;
composition of, 372.

Bone-char, 369;
composition of, 372.

Bone-dust, 360.

Bone-meal, 361, 364;
composition of, 371;
condition of nitrogen in, 540.

Bone-phosphate, 385.

Bones, 359-372;
action of, 365;
boiled, 361;
bruised, 361;
capable of nitrification, 182;
collected in Britain, 353, 362;
composition of, 362, 371;
compound, 372;
crops suited for, 368;
dissolved, 368, 371;
early use of, 359;
fermentation of, 361;
floated, 365;
forms of, 360;
grinding of, 365;
imports of, 151;
inorganic matter in, 363;
nitrogen in, 151;
organic matter in, 363;
putrefaction of, 365, 366;
raw, 361;
source of nitrogen, 151;
treatment of, 364.

Bonnet, Charles, discovery of source of plant's carbon by, 11.

Boracic acid in _salinas_, 335.

Bordeaux phosphate, 379.

Boussingault, on dry matter in horse-manure, 243;
early researches of,
in agricultural chemistry, 21;
experiments by, on nitrification, 185, 198;
on excrements of pig, 250;
on nitrates in guano, 304;
on nitrogen in plants, 41, 42;
on nitrogen in soil, 124;
on nitrogen in excreta, 234;
on nitrogen lost during fermentation, 245.

Bracken-fern, analyses of, 283;
as litter, 241.

Bran, manurial constituents in, 282.

Bretschneider on sources of plant-nitrogen, 42.

Brewers' grain, manurial constituents in, 282.

Bromine in ash of plants, 55.

Browse Island guano, 309, 328;
phosphoric acid in, 330.

Bruestlein and Peters on fixation of bases and acids by soil, 59.

Buckland, Dr, discovery of coprolites by, 373.

Buckwheat absorbs ammonia, 352.

Bull River, phosphates from, 376.

Cabbages, benefited by saline manures, 529;
manuring of, 528-529;
soils suited for, 529.

Caird, Sir James, experiments by, with Peruvian guano, 301.

Calcareous earth, absorptive power of, 98;
stones, phosphoric acid in, 211.

Calcium phosphate in Chincha guano, 305.

Calcium sulphate in concretionary nodules, 328.

_Caliche_, composition of, 342;
occurrence of, 341.

California, guano deposits at, 328.

Cambridgeshire, coprolites from, 373.

Cameron, Sir Charles, on assimilation of urea by plants, 46.

Canadian apatite, 201, 374.

Cape Vert guano, phosphoric acid in, 330.

Carbolic acid, action of, on nitrifying organisms, 177.

Carbon, fixation of, by plants, 37;
in plants, discovery of source of, 11.

Carbon bisulphide, effect of, on nitrification, 166, 176.

Carbonate of ammonia formed in fermentation of dung, 247, 258.

Carbonic acid, absorbed by plants, 12
--by soil, 81;
in ash of plants, 55;
oxidation of, by bacteria, 95;
produced in decomposition of farmyard manure, 258.

Carbonising-works, ammonia from, 353, 358.

Carburetted hydrogen, produced in decomposition of farmyard manure, 258.

Caribbean phosphates, 379.

Carnallite, 420.

Carolina phosphate, 376.

Carrots, manurial constituents in, 282.

Catacombs, bones from, 360.

Catch-cropping, 138, 489.

Cattle foods, average composition of, 557.

Caustic lime, 453.

Cereals, manuring of, 493-504;
nitrogenous manures benefit, 494;
potash in, 217;
silicates absorbed by, 494;
value of nitrate of soda as manure for, 346.

Chalk, an adulterant of guano, 319;
lias, phosphoric acid in, 211.

Charcoal, a filter for sewage, 437.

Charleston phosphate, 376.

Chemical analysis of manures, interpretation of, 539;
value of, 539.

Chemical composition of soil, 87-92.

Cheshire, bones used in, 360.

Chesterfield Island guano, 309.

Chili and Peru, chief source of nitrate of soda, 162.

Chincha Island guano, 302, 303, 327;
composition of, 305;
nitrogen in, 329;
phosphoric acid in, 329.

Chipana, guano deposits at, 327.

Chlorapatite, composition of, 210.

Chlorine in ash of plants, 55.

Chloroform prevents nitrification, 166, 176.

Chlorophyll, organisms destitute of, 169;
produced by nitrate of soda, 347;
relation of, to fixation of carbon by plants, 37.

Chuca, 341.

Citrate of ammonia, solubility of phosphates in, 408.

Clay, absorptive power of, 68;
analysis of, 107;
grey, evaporation of water from, 99;
loamy, evaporation of water from, 99;
sandy, absorptive power of, 98
--evaporation of water from, 99;
soils, benefited by basic slag, 414
--puddling in, 455;
stiffish, evaporation of water from, 99;
strong absorptive power of, 98.

Clover-hay, fertilising ingredients removed from soil by, 486;
manurial constituents in, 282;
manuring of, 522.

Clover-sickness, 522.

Coal, nitrogen in, 353.

Coke-works, ammonia from, 353, 358.

Colloids, 491.

Colour of soil, 80;
difference in temperature due to, 80.

Columbia, guano deposits at, 327.

Composts, 113, 445-448;
farmyard manure a typical, 446;
manufacture of, 445;
object of, 445;
purposes served by, 445;
substances used for, 447.

Compound bones, 372.

Concretionary nodules, composition of, 328.

Conglomerate, 341.

Connecticut, experimental station at, 33.

Cooke, F. J., on, farmyard manure, 272, 277;
field experiments. 547;
manuring of barley, 497
--of mangels, 514
--of meadow-land, 509
--of swedes, 514
--of wheat, 501.

Copper, oxide of, in plants, 55.

Copperas, as a fixer, 246, 247.

Coprolites, 373;
percentage of phosphates in, 201:
occurrence of, 201, 373.

Corcovado guano, nitrogen in, 329;
phosphoric acid in, 329.

Cordilleras, 340, 341.

Costra, 341.

Cotton-cake, decorticated, manurial constituents in, 282.

Cotton-cake, undecorticated, manurial constituents in, 282.

Cotton-seeds, imports of, 153.

Cova, 341.

Covered manure, potatoes grown with, 289;
wheat grown with, 289.

Cow-dung, alkalies in, 226;
composition of, in dry state, 227;
cool, 225;
nitrogen in, 226;
phosphoric acid in, 226;
water in, 226.

Cow-manure, 247;
amount voided per day, 248;
amount voided per year, 248;
analysis of, 286;
dry matter in, 248;
fermentation in, slow, 248;
mineral matter in, 248;
mucilaginous matter in, 248;
nitrogen in, 248;
resinous matter in, 248.

Cow-urine, alkalies in, 230;
composition of, in dry state, 231;
fertilising ingredients in, for food consumed, 232;
nitrogen in, 230;
phosphoric acid in, 230;
water in, 230.

Cows, percentage of food voided in excrements of, 281;
solid excrements of, 280;
urine voided by, 280.

Cress, experiments with, 41.

Crimea, bones from, 360.

Cropped soils, nitrates in, 157
--lost by drainage in, 141.

Crops, capacity of, for assimilating manures, 486;
difference in root-systems of, 488;
manuring of common farm, 493-530;
period of growth of, 489;
potash removed in, 218;
suited for sewage, 434;
variation in composition of, 490.

Crusius on phosphoric acid removed from the farm, 207.

Crust guanos, 308, 379.

Crystalloids, 491.

Curacao phosphates, 308, 330, 379.

Darmstadt experiments with basic slag, 410-413.

Darwin on origin of nitrate-fields, 335.

Daubeny on mineral sources of phosphoric acid, 200.

Davy, Sir Humphry, lectures of, on agricultural chemistry, 17-19;
on heat and water absorbing and retaining properties of soils, 57;
on hygroscopic power of soils, 99.

Deherain, on nitrification, 52;
on nitrification in sulphate of ammonia, 191;
on rate of nitrification, 186.

Denitrification, 177;
conditions favourable for, 178;
effected by bacteria, 178.

Derby, Lord, introduction of Peruvian guano by, 301.

Detmer on humus in soil, 47.

Dew, action of, on guano, 300;
explanation of, 77;
most abundant in summer, 78.

Dicalcic phosphate, 387;
formula of, 398;
molecular composition of, 398;
percentage composition of, 398.

Digby, Sir Kenelm, on value of nitrates to plants, 45;
theory of, on plant-food, 6-8.

Diorite, phosphoric acid in, 202, 211.

Direct manures, 113.

Dissolved-bone compound, 372.

Dissolved bones, 368; composition of, 371.

Dissolved guano, 310.

Dolerite, phosphoric acid in, 202, 211.

Dolomite, phosphoric acid in, 202, 211.

Downton experiments on sewage-sludge, 439.

Drainage, average of thirteen years, 160;
nitrates in, 160;
nitrates lost by, 140;
phosphoric acid lost by, 206;
potash lost by, 217.

Drainings of manure-heaps, analysis of, 290.

Dried blood, 424;
composition of, 424;
manure for sugar-cane, 425;
potash in, 219;
rate of nitrification in, 192;
source of nitrogen, 152;
suited for horticulture, 425.

Dried flesh, 425;
nitrogen in, 425.

Dried leaves, as litter, 242;
composition of, 242;
nitrogen in, 242;
phosphoric acid in, 242;
potash in, 242.

Ducks' dung, analysis of, 331.

Duhamel and Hales, theory of, on plant-growth, 8.

Dundonald, Earl, treatise by, on agricultural chemistry, 13.

Dung and urine, composition of, 234.

Dutrochet on absorption of plant-food, 55.

Dyer, Dr Bernard, analyses of stable manure by, 283;
experiments on peat as litter, 240;
on nitrate of soda as manure for mangolds, 349.

Earth, an adulterant of guano, 319;
composition of solid crust of, 102.

Ecuador, guano deposits at, 327.

Egyptian guano, nitrogen in, 329;
phosphoric acid in, 329.

Elbe, waters of, phosphoric acid in, 206;
potash in, 217.

Elm-tree, water transpired by, 71.

Enderbury Island guano, 309, 328;
phosphoric acid in, 328.

Endosmosis, 55.

English farming, 86.

Equalised guano, 311.

Essex, coprolites from, 374.

Estremadura phosphate, 375.

Ethylamine, nitrification in, 182.

Evaporation from soil, 71, 72, 98.

Excreta, amount of nitrogen in, 149, 292;
composition of, 226, 292;
difference in amount of, for food consumed, 279;
liquid, in farmyard manure, 224;
solid, in farmyard manure, 224;
solid, undigested food in, 224;
solid, voided by cows, 280, 292;
solid, voided by horse, 292;
solid, voided by oxen, 280;
solid, voided by sheep, 280, 292.

Factors for calculating manurial ingredients
into their different compounds, 553.

Falkland guano, 308;
nitrogen in, 330;
phosphoric acid in, 330.

Fallow-fields, nitrates formed in, 188.

Fanning Island guano, 328;
phosphoric acid in, 330.

Farmyard manure, 223-292;
action of, on soils, 273;
ammonia in, 258;
amount produced on farm per year, 252;
analyses of, 259, 286;
application of, 264;
ash of, 287, 288;
carbonic acid gas in, 258;
classes of constituents of, 224;
compared with artificials, 476;
composition of, 259;
denitrification in, 179;
depth to plough to, 267;
effect of, on potatoes, 520;
fertilising matter in, 270;
fire-fang in, 264;
fresh, composition of, 286, 288;
functions of, 268;
heat in fermentation of, 78, 253;
humates in, 259;
humic acid in, 258;
inadequate source of nitrogen to soil, 271;
indirect influence of, 273;
influence of, on soil, 475;
Lawes, Sir John, on composition of, 291;
Lord Kinnaird's experiments with, 289;
marsh-gas in, 258;
mineral matter in, 260;
moisture in, 260;
nitric acid in, 259;
nitrogen in, 260;
ratio of, to ash ingredients, 271;
organic matter in, 260;
phosphoretted hydrogen in, 258;
phosphoric acid in, 260;
potash in, 260;
products of decomposition of, 257;
rate of application of, 275;
retrogression of nitrogen in, 142;
rotten, composition of, 287, 288
--value of, 261;
rotting, effects of, on, 262;
solid excreta in, 224;
sulphuretted hydrogen in, 258;
supplemented with nitrogen, 271;
supplemented with phosphoric acid, 272;
temperature, effect of, on soil, 79, 274;
typical compost, 446;
ulmates in, 259;
ulmic acid in, 258;
unfavourable to certain crops, 477;
urine in, 228;
value of, 268;
variation in composition of, 223;
water in, 258.

Fatty acids in guano, 305.

Felspars, 103;
albite, 103;
composition of, 103;
labradorite, 220;
oligoclase, 103, 214, 220;
orthoclase, 103, 214, 220;
phosphoric acid in, 211;
potash manures, 213;
potash in, percentage of, 213, 220.

Ferment, aerobic, 173, 255;
anaerobic, 255.

Fermentation, ammonium carbonate formed during, 245;
in bones, 365;
heat of, 79;
of farmyard manure, 253;
of guano, 299;
temperature of, 256.

Fern, bracken, as litter, 241.

Ferric chloride, test for sulphocyanates, 355.

Fertilisers and Feeding Stuffs Act, 543.

Fertilising ingredients, amount of soluble, in soil, 90;
amounts removed by different crops, 484, 485;
chemical condition of, in soil, 89;
lodge in seed, 491;
in soil, 87.

Fertility, of the soil, 65-97;
potential, of soil, 214, 549;
properties necessary for, 66;
supply of oxygen necessary for, 81.

Field experiments, 545, 548;
educational value of, 547;
on rate of nitrification, 187.

Finger-and-toe prevented by lime, 461.

Fire-fang in farmyard manure, 264.

Fischer on absorption of plant-food, 55.

Fish-guano, 320-323;
application of, 323;
consumption of, 152;
manufacture of, 321;
nitrogen in, 321;
phosphoric acid in, 321;
production of, 322;
source of nitrogen, 152;
value of, 322.

Fixers, 246;
chemical reactions with, 284.

Fleece, potash in, 217.

Fleischer, Professor, on solubility of phosphates, 408.

Flesh-guano, 320.

Flint Island guano, 309.

Flitcham experiments on growth of wheat, 500.

Floated bones, 362, 365.

Florida phosphate, 378.

Fluorapatite, composition of, 210.

Food, consumed by pigs, 281;
dry matter of, voided in dung, 228;
percentage of, in excrements, 281.

Food-constituents, plant, necessary for nitrification, 170.

Forbes, David, on nitrate-fields of Chili, 334.

Forest-soils, absence of nitrification in, 193.

Fowl-dung, 320, 326;
analysis of, 331.

Fownes on phosphoric acid in rocks, 202.

Frankland, P. F., experiments on nitrification, 52, 167, 198.

Franklin, Benjamin, experiment of, with gypsum, 462.

Frey Bentos, meat-meal guano from, 324.

Galapagos Islands, guano deposits at, 327.

Garden earth, absorptive power of, 98;
ammonia in, 128.

Gas-liquor, ammonia in, 353.

Gas-works, ammonia from, 353, 358.

Gases, absorbed by soils, 81;
present in soil, 100.

Gazzeri on retention by soil of plant-food, 57.

Geese-dung, analysis of, 331.

Geic acid in humus, 47.

Gelatin, nitrification in, 182;
from bones, 364.

Germany, agricultural research in, 32;
bones imported from, 360;
manufacture of meat-meal guano in, 324.

Germination, influence of temperature on, 76;
oxygen necessary for, 81.

Gilbert, Sir J. Henry, on barley-manuring, 496;
on Liebig's mineral theory, 28;
on manuring of potatoes, 520;
Presidential address of, 61;
and see Lawes and Gilbert.

Glauber on artificial production of nitre, 164.

Glue, 364.

Glycin, assimilated by plants, 47.

Glycocoll, experiments with, 46.

Gneiss, 106;
phosphoric acid in, 207.

Grandeau, Professor, on forms of plant-food in soil, 107;
on loss of phosphoric acid, 207.

Granite, 105;
in guano, 303;
phosphoric acid in, 202, 211;
potash in, 214.

Grass, Bangor experiments on, 508;
effect of manure on, 505;
influence of farmyard manure on, 506;
manuring of, 504-510.

Gray, Asa, on transpiration by plants, 71.

Great Cayman guano, 379.

Green manures, 113.

Grouven on guano, 313.

Guanape Island guano, 302, 327;
nitrogen in, 329;
phosphoric acid in, 329.

Guanine, 304;
experiments with, 46.

Guano, 293-331;
action of, as a manure, 312;
adulteration of, 318;
application of, 315;
bat, 325;
composition of, 305, 329;
crust, 308;
deposits of the world, 327;
dissolved, 310;
equalised, 309;
fermentation of, 299;
fertilising constituents in, 314;
fish, 320-323;
importance of, in agriculture, 293;
inequality in composition of, 309;
influence of, on farming, 294;
meat-meal, 324;
mode of application of, 315;
nitrification in, rate of, 192;
nitrogenous, 300-308;
origin of, 297;
Peruvian, 300-306;
phosphatic, 308;
quantity to apply, 317;
rectified, 311;
so-called, 320;
source of phosphoric acid, 202;
source of potash, 219;
value of, as a manure, 296;
variation in composition of, 299.

Gulf of Mexico, guano deposits at, 328.

Gulls, guano from, 297.

Gunning on sources of plant-nitrogen, 42.

Gunpowder, exports of, 149;
nitrogen lost in, 149;
production, annual, of, 149;
saltpetre in, 149, 333.

Gypsum, 462-464;
absorptive power of, 98;
action of, mode of, 462--on nitrification, 173;
an adulterant of guano, 319;
as a fixer, 246, 247, 285;
decomposes double silicates, 463;
favourable to clover, 464;
as an oxidising agent, 464.

Hales, Stephen, theory of, on plant-growth, 8.

Hampe, Dr, on nitrogen in plants, 46.

Harting on sources of plant-nitrogen, 42.

Heat, of soils, 76-78;
of fermentation, 78.

Heiden, Dr, on application of farmyard manure, 265;
on fixation of bases and acids by soil, 59;
on loss of ammonia from dung, 249;
on percentage of food voided by animals, 253;
on straw as litter, 244, 249.

Hellriegel, on amount of water in soils, 75;
on barley, 498;
on nitrogen in plants, 44.

Helmont, Van, theory of, on source of plant-food, 4.

Henslow, Professor, on coprolites, 374.

Heraues on organisms in soil, 95.

Herbage, effect of manure on, 505.

Herrings as manure, 321.

Herve-Mangon, experiments on action of light on plants by, 38.

Hilgenstock on tetracalcic phosphate, 405.

Hippuric acid, experiments with, 46;
in farmyard manure, 257.

Hire, De la, on evolution of gases by plants, 11.

Hofmeister on horse excrements, 243.

Hoof-guano, source of nitrogen, 152.

Hoofs and horns, manure from, 425.

Hops, manuring of, 528;
potash removed by, 217;
slow-acting manures benefit, 528.

Horn, capable of nitrification, 182;
as manure, 425;
nitrogen in, 426;
phosphoric acid in, 426.

Hornblende, 105.

Horse-dung, alkalies in, 226;
composition of, in dry state, 227;
hot, 225;
nitrogen in, 225, 226;
phosphoric acid in, 226;
water in, 225, 226.

Horse-manure, 242;
amount produced per day, 243;
amount produced per year, 243;
analyses of, 283;
dry matter in, 243;
dry nature of, 245;
fermentation rapid in, 245;
mineral matter in, 243;
nitrogen in, 243, 244.

Horse-urine, alkalies in, 230;
composition of, in dry state, 231;
fertilising ingredients in, 232;
nitrogen in, 230;
phosphoric acid in, 230;
water in, 230.

Hosaeus on assimilation of ammonia, 50.

Howland Island guano. 309, 328;
phosphoric acid in, 330.

Huanillos, guano from, 302, 327;
nitrogen in, 330;
phosphoric acid in, 330.

Huano, 297.

Hueppe on organisms in soil, 95.

Hughes, John, on bracken-fern as litter, 241;
on composition of bracken, 283.

Humates in farmyard manure, 259.

Humboldt, A., discovery of Peruvian guano by, 300.

Humic acid in farmyard manure, 258;
in humus, 47.

Humin in humus, 47.

Humus, absorptive power of, 68, 98;
evaporation from, 99;
nature of, in soil, 47;
soils improved by addition of, 273.

Huon Island guano, 309, 328;
phosphoric acid in, 330.

Huxtable and Thompson on retention of plant-food by soil, 57.

Hydrated silicates, 107, 459.

Hydrochloric acid as a fixer, 245.

Hydrogen, amount of, in plants, 40;
source of, in plants, 40.

Hygroscopic power of soils, 75.

Ichaboe guano, 307;
nitrogen in, 329;
phosphoric acid in, 329.

Independence Bay guano, 302, 327;
nitrogen in, 329;
phosphoric acid in, 329.

India, nitre soils of, 162.

Indirect manures, 113, 114, 449-473.

Ingenhousz, John, experiments by, on nitrogen in plants, 41;
on oxygen evolved by plants, 12.

Insoluble phosphate, 386;
value of, 396.

Iodine, in ash of plants, 55;
in nitrate of soda, 340, 342.

Iquique, nitrate of soda from, 333.

Iron in ash of plants, 54;
necessary for plant-growth, 55;
reversion in superphosphates caused by, 390, 399.

Iron-works, ammonia from, 353, 355, 358.

Irrigation, 431-433;
intermittent, 434;
subsoil, 432.

Jamieson, Professor, experiments with coprolites, 380.

Jarvis Island guano, 309, 328;
phosphoric acid in, 330.

Jersey, manuring of potatoes in, 521.

Johnson, Professor S. W., on application of superphosphate, 395;
on Earl Dundonald, 13;
on nitrogen in buffalo-horn shavings, 426;
on nitrogen in soils, 123;
on solubility of basic slag, 408;
value of organic nitrogen to plant, 46.

Juergensen on nitrogen in excreta, 234.

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Manures and the principles of manuringChapter XXVI: The Rothamsted Experiments (1)

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