Chapter XXVII

LAWES AND GILBERT’S EXPERIMENTS ON WHEAT.

I hardly know how to commence an account of the wonderful experiments made at Rothamsted, England, by John Bennett Lawes, Esq., and Dr. Joseph H. Gilbert. Mr. Lawes’ first systematic experiment on wheat, commenced in the autumn of 1843. A field of 14 acres of rather heavy clay soil, resting on chalk, was selected for the purpose. Nineteen plots were accurately measured and staked off. The plots ran the long way of the field, and up a slight ascent. On each side of the field, alongside the plots, there was some land not included, the first year, in the experiment proper. This land was either left without manure, or a mixture of the manures used in the experiments was sown on it.

I have heard it said that Mr. Lawes, at this time, was a believer in what was called “Liebig’s Mineral Manure Theory.” Liebig had said that “The crops on a field, diminish or increase in exact proportion to the diminution or increase of the mineral substances conveyed to it in manure.” And enthusiastic gentlemen have been known to tell farmers who were engaged in drawing out farm-yard manure to their land, that they were wasting their strength; all they needed was the mineral elements of the manure. “And you might,” they said, “burn your manure, and sow the ashes, and thus save much time and labor. The ashes will do just as much good as the manure itself.”

Whether Mr. Lawes did, or did not entertain such an opinion, I do not know. It looks as though the experiments the first year or two, were made with the expectation that mineral manures, or the ashes of plants, were what the wheat needed.

The following table gives the kind and quantities of manures used per acre, and the yield of wheat per acre, as carefully cleaned for market. Also the total weight of grain per acre, and the weight of straw and chaff per acre.

The following eight tables are shown in “thumbnail” form. The full-width versions can be viewed below.

Experiments at Rothamsted on the Growth of Wheat, Year after Year, on the same Land.

TABLE 1.—MANURES AND PRODUCE; 1ST SEASON, 1843-4. MANURES AND SEED (OLD RED LAMMAS) SOWN AUTUMN 1843.

Manures Produce

FM Farmyard Manure. FMA Farmyard Manure Ashes.¹ SiP Silicate of Potass.² PhP Phosphate of Potass.³ PhS Phosphate of Soda.³ PhM Phosphate of Magnesia.³ SPL Superphosphate of Lime.³ SAm Sulphate of Ammonia. RC Rape Cake. Wt/Bu. Weight per Bushel. OC Offal Corn.⁵ C Corn. TC Total Corn. S&C Straw and Chaff. TP Total Produce. TP Total Produce (Corn and Straw). C100 Corn to 100 Straw.

P l o t s. Manures per Acre. Produce per Acre, etc. Increase per Acre by Manure.

Dressed corn.

FM FMA SiP PhP PhS PhM SPL SA RC Quantity⁵ Wt/Bu. OC TC S&C TP C&S C S&C TP C100

Tons. Cwts. lbs. lbs. lbs. lbs. lbs. lbs. lbs. Bush. Pks. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs.

0 Mixture of the residue of most of the other manures. .. 19 3¾ 58.5 61 1228 1436 2664 305 316 621 85.5

1 .. .. .. .. .. .. 700 .. 154 16 3 59.0 52 1040 1203 2243 117 83 200 86.4

2 .. .. .. .. .. .. .. .. .. 20 1¾ 59.3 64 1276 1476 2752 353 356 709 86.4

3 Unmanured. .. .. .. .. .. .. .. 15 0 58.5 46 923 1120 2043 .. .. .. 82.4

4 .. 32¹ .. .. .. .. .. .. .. 14 2¼ 58.0 44 888 1104 1992 -35 -16 -51 80.4

5 .. .. .. .. .. .. 700 .. .. 15 2¼ 58.3 48 956 1116 2072 33 -4 29 85.6

6 .. .. .. .. .. 420 350 .. .. 15 1 60.0 48 964 1100 2064 41 -20 21 87.6

7 .. .. .. .. 325 .. 350 .. .. 15 2 60.3 49 984 1172 2156 61 52 113 84.0

8 .. .. .. 375 .. .. 350 .. .. 15 0¾ 61.3 49 980 1160 2140 57 40 97 84.5

9 .. .. .. .. .. .. 630 .. .. 19 2¼ 62.3 54 1280 1368 2048 357 248 605 93.5

10 .. .. 220 .. .. .. 560 .. .. 15 1¾ 62.0 50 1008 1112 2120 85 -8 77 90.6

11 .. .. .. .. .. .. 350 .. 308 17 0¾ 61.8 56 1116 1200 2316 193 80 273 93.0

12 .. .. .. .. 162½ 210 350 .. .. 15 2 61.5 50 1004 1116 2120 81 -4 77 90.0

13 .. .. .. 187½ .. 210 350 .. .. 16 1¼ 62.5 54 1072 1204 2276 149 84 233 89.0

14 .. .. 275 .. .. 210 350 .. .. 15 3 61.3 51 1016 1176 2192 93 56 149 86.4

15 .. .. 110 150 .. 168 350 .. .. 16 3¼ 62.0 58 1096 1240 2336 173 120 293 88.4

16 .. .. 110 .. .. .. 350 .. .. 19 3¼ 62.5 65 1304 1480 2784 381 360 741 88.1

17 .. .. 110 .. .. .. 350⁴ .. .. 18 3¾ 62.3 62 1240 1422 2662 317 302 619 87.2

18 .. .. 110 .. .. .. 350 .. 154 20 3¾ 62.0 63 1368 1768 3136 415 618 1093 77.4

19 .. .. 110 .. .. 105 350 .. .. 24 1¼ 61.8 79 1580 1772 3352 657 652 1309 89.2

20 Unmanured. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ..

21 Mixture of the residue of most of the other manures. .. .. .. .. .. .. .. .. .. .. .. ..

22 .. .. .. .. .. .. .. .. .. .. .. ..

These were the results of the harvest of 1844. The first year of these since celebrated experiments.

If Mr. Lawes expected that the crops would be in proportion to the minerals supplied in the manure, he must have been greatly disappointed. The plot without manure of any kind, gave 15 bushels of wheat per acre; 700 lbs. of superphosphate of lime, made from burnt bones, produced only 38 lbs. or about half a bushel more grain per acre, and 4 lbs. less straw than was obtained without manure. 640 lbs. of superphosphate, and 65 lbs. of commercial sulphate of ammonia (equal to about 14 lbs. of ammonia), gave a little over 19½ bushels of dressed wheat per acre. As compared with the plot having 700 lbs. of superphosphate per acre, this 14 lbs. of available ammonia per acre, or, say 11½ lbs. nitrogen, gave an increase of 324 lbs. of grain, and 252 lbs. of straw, or a total increase of 576 lbs. of grain and straw.

On plot No. 19, 81 lbs. of sulphate ammonia, with minerals, produces 24¼ bushels per acre. This yield is clearly due to the ammonia.

The rape-cake contains about 5 per cent of nitrogen, and is also rich in minerals and carbonaceous matter. It gives an increase, but not as large in proportion to the nitrogen furnished, as the sulphate of ammonia. And the same remarks apply to the 14 tons of farm-yard manure.

We should have expected a greater increase from such a liberal dressing of barn-yard manure. I think the explanation is this: The manure had not been piled. It was probably taken out fresh from the yard (this, at any rate, was the case when I was at Rothamsted), and plowed under late in the season. And on this heavy land, manure will lie buried in the soil for months, or, if undisturbed, for years, without decomposition. In other words, while this 14 tons of barn-yard manure, contained at least 150 lbs. of nitrogen, and a large quantity of minerals and carbonaceous matter, it did not produce a bushel per acre more than a manure containing less than 12 lbs. of nitrogen. And on plot 19, a manure containing less than 15 lbs. of available nitrogen, produced nearly 4 bushels per acre more wheat than the barn-yard manure containing at least ten times as much nitrogen.

There can be but one explanation of this fact. The nitrogen in the manure lay dormant in this heavy soil. Had it been a light sandy soil, it would have decomposed more rapidly and produced a better effect.

As we have before stated, John Johnston finds, on his clay-land, a far greater effect from manure spread on the surface, where it decomposes rapidly, than when the manure is plowed under.

The Deacon was looking at the figures in the table, and not paying much attention to our talk. “What could a man be thinking about,” he said, “to burn 14 tons of good manure! It was a great waste, and I am glad the ashes did no sort of good.”

After the wheat was harvested in 1844, the land was immediately plowed, harrowed, etc.; and in a few weeks was plowed again and sown to wheat, the different plots being kept separate, as before.

The following table shows the manures used this second year, and the yield per acre:

Experiments at Rothamsted on the Growth of Wheat, Year after Year, on the same Land.

TABLE II.—MANURES AND PRODUCE; 2ND SEASON, 1845. MANURES AND SEED (OLD RED LAMMAS) SOWN MARCH 1845.

Manures Produce

FM Farmyard Manure. SiP Silicate of Potass.¹ PhP Phosphate of Potass.² SPL Superphosphate of Lime.² B-A Bone-ash. MAc Muriatic Acid. G Guano. SAm Sulphate of Ammonia. MAm Muriate of Ammonia. CAm Carbonate of Ammonia. RC Rape Cake. T Tapioca. Wt/Bu. Weight per Bushel. OC Offal Corn.⁵ C Corn. TC Total Corn. S&C Straw and Chaff. TP/C&S Total Produce (Corn and Straw). TP Total Produce. OC/100 Offal Corn to 100 Dressed. C100 Corn to 100 Straw.

P l o t s. Manures per Acre. Produce per Acre, etc. Increase per Acre by Manure.

Dressed corn.

FM SiP PhP SPL B-A MAc G SAm MAm CAm RC T Quantity⁵ Wt/Bu. OC TC S&C TP C&S C S&C TP OC 100 C100

Tons. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. Bush. Pks. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs.

0 Mixture of the residue of most of the other manures. .. .. .. 32 0 56.5 159 1967 3977 5944 526 1265 1791 10.9 49.5

1 .. 112 .. .. .. .. .. 224 .. .. 560 .. 26 1¼ 54.8 248 1689 3699 5388 248 987 1235 17.3 45.7

2 14 .. .. .. .. .. .. .. .. .. .. .. 32 0 56.8 151 1967 3915 5882 526 1203 1729 8.9 50.2

3 Unmanured. .. .. .. .. .. .. .. .. .. .. 23 0¾ 56.5 131 1441 2712 4153 .. .. .. 8.7 53.1

4 .. .. .. .. 112 112 .. 112 .. .. .. .. 29 2½ 58.0 161 1879 3663 5542 438 951 1389 9.4 51.3

5⁴{1 Unmanured. .. .. .. .. .. .. .. .. .. .. 22 2¼ 57.5 134 1431 2684 4115 -10 -28 -38 10.1 53.3

{2 .. .. .. .. .. .. .. .. .. 252³ .. .. 26 3¾ 57.3 190 1732 3599 5331 291 887 1178 14.2 48.1

6 .. .. .. 112 .. .. .. 112 .. .. 560 .. 28 2¾ 57.8 214 1871 3644 5515 430 932 1362 14.1 57.3

7 .. .. .. 112 .. .. .. 112 .. .. .. 560 26 2¾ 57.0 161 1682 3243 4925 241 531 772 11.3 51.9

8 .. .. .. .. .. .. .. 112 .. .. 560 .. 27 0½ 56.3 164 1716 3663 5379 275 951 1226 14.0 46.9

9 .. .. .. .. .. .. .. 168⁵ 166⁵ .. .. .. 33 1½ 58.3 187 2131 4058 6189 690 1346 2036 10.2 52.5

10 .. .. .. .. .. .. .. 168⁶ 168⁶ .. .. .. 31 3¼ 56.3 191 1980 4266 6216 539 1554 2093 12.3 46.4

11 .. .. .. 280 .. .. .. 224 .. .. 560 .. 30 3 56.0 158 1880 4101 5981 439 1392 1831 11.3 45.8

12 .. .. 280 .. .. .. .. 224 .. .. .. .. 28 2¼ 55.8 264 1842 4134 5976 401 1422 1823 17.8 44.5

13 .. .. .. .. .. .. 336⁷ .. .. .. .. .. 25 0 56.3 152 1558 3355 4913 117 643 760 12.0 46.4

14 .. .. .. .. .. .. 672⁸ .. .. .. .. .. 27 1 57.5 176 1743 3696 5439 302 981 1286 16.2 47.1

15 .. .. .. .. 224 224 .. 224 .. .. .. .. 32 3¾ 57.3 209 2103 4044 6147 662 1332 1994 11.8 52.0

16 .. .. .. 224 .. .. .. 56 56 .. 560 .. 32 2¼ 56.3 182 2028 4191 6219 587 1479 2066 11.1 48.4

17 .. .. .. 224 .. .. .. 112 112 .. 280 .. 32 0¾ 55.8 299 2093 3826 5919 652 1114 1766 15.2 54.7

18 .. .. .. 336 .. .. .. 112 112 .. .. .. 33 1¼ 56.5 180 2948 3819 3867 607 1107 1714 11.2 53.6

19 .. .. .. .. 112 112 .. 112 .. .. 390 .. 34 3 57.0 133 2114 4215 6329 673 1503 2176 9.1 50.2

20 Unmanured. .. .. .. .. .. .. .. .. .. .. 24 2¾ 56.0 113 1495 3104 4599 54 392 446 9.7 48.2

21} Mixture of the residue of most of the other manures. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ..

22} .. .. .. .. .. .. .. .. .. .. .. .. .. .. ..

The season of 1845 was more favorable for wheat, than that of 1844, and the crops on all the plots were better. On plot No. 3, which had no manure last year, or this, the yield is 23 bushels per acre, against 15 bushels last year.

Last year, the 14 tons of barn-yard manure gave an increase of only 5¼ bushels per acre. This year it gives an increase of nearly 9 bushels per acre.

“Do you mean,” said the Deacon, “that this plot, No. 2, had 14 tons of manure in 1844, and 14 tons of manure again in 1845?”

“Precisely that, Deacon,” said I, “and this same plot has received this amount of manure every year since, up to the present time—for these same experiments are still continued from year to year at Rothamsted.”

“It is poor farming,” said the Deacon, “and I should think the land would get too rich to grow wheat.”

“It is not so,” said I, “and the fact is an interesting one, and teaches a most important lesson, of which, more hereafter.”

Plot 5, last year, received 700 lbs. of superphosphate per acre. This year, this plot was divided; one half was left without manure, and the other dressed with 252 lbs. of pure carbonate of ammonia per acre. The half without manure, (5a), did not produce quite as much grain and straw as the plot which had received no manure for two years in succession. But the wheat was of better quality, weighing 1 lb. more per bushel than the other. Still it is sufficiently evident that superphosphate of lime did no good so far as increasing the growth was concerned, either the first year it was applied, or the year following.

The carbonate of ammonia was dissolved in water and sprinkled over the growing wheat at three different times during the spring. You see this manure, which contains no mineral matter at all, gives an increase of nearly 4 bushels of grain per acre, and an increase of 887 lbs. of straw.

“Wait a moment,” said the Deacon, “is not 887 lbs. of straw to 4 bushels of grain an unusually large proportion of straw to grain? I have heard you say that 100 lbs. of straw to each bushel of wheat is about the average. And according to this experiment, the carbonate of ammonia produced over 200 lbs. of straw to a bushel of grain. How do you account for this.”

“It is a general rule,” said I, “that the heavier the crop, the greater is the proportion of straw to grain. On the no-manure plot, we have, this year, 118 lbs. of straw to a bushel of dressed grain. Taking this as the standard, you will find that the increase from manures is proportionally greater in straw than in grain. Thus in the increase of barn-yard manure, this year, we have about 133 lbs. of straw to a bushel of grain. I do not believe there is any manure that will give us a large crop of grain without a still larger crop of straw. There is considerable difference, in this respect, between different varieties of wheat. Still, I like to see a good growth of straw.”

“It is curious,” said the Doctor, “that 3 cwt. of ammonia-salts alone on plots 9 and 10 should produce as much wheat as was obtained from plot 2, where 14 tons of barn-yard manure had been applied two years in succession. I notice that on one plot, the ammonia-salts were applied at once, in the spring, while on the other plot they were sown at four different times—and that the former gave the best results.”

The only conclusion to be drawn from this, is, that it is desirable to apply the manure early in the spring—or better still, in the autumn.

“You are a great advocate of Peruvian guano,” said the Deacon, “and yet 3 cwt. of Peruvian guano on Plot 13, only produced an increase of two bushels and 643 lbs. of straw per acre. The guano at $60 per ton, would cost $9.00 per acre. This will not pay.”

This is an unusually small increase. The reason, probably, is to be found in the fact that the manure and seed were not sown until March, instead of in the autumn. The salts of ammonia are quite soluble and act quickly; while the Peruvian guano has to decompose in the soil, and consequently needs to be applied earlier, especially on clay land.

“I do not want you,” said the Deacon, “to dodge the question why an application of 14 tons of farmyard-manure per acre, every year for over thirty years, does not make the land too rich for wheat.”

“Possibly,” said I, “on light, sandy soil, such an annual dressing of manure would in the course of a few years make the land too rich for wheat. But on a clayey soil, such is evidently not the case. And the fact is a very important one. When we apply manure, our object should be to make it as available as possible. Nature preserves or conserves the food of plants. The object of agriculture is to use the food of plants for our own advantage.”

“Please be a little more definite,” said the Deacon, “for I must confess I do not quite see the significance of your remarks.”

“What he means,” said the Doctor, “is this: If you put a quantity of soluble and available manure on land, and do not sow any crop, the manure will not be wasted. The soil will retain it. It will change it from a soluble into a comparatively insoluble form. Had a crop been sown the first year, the manure would do far more good than it will the next year, and yet it may be that none of the manure is lost. It is merely locked up in the soil in such a form as will prevent it from running to waste. If it was not for this principle, our lands would have been long ago exhausted of all their available plant-food.”

“I think I understand,” said the Deacon; “but if what you say is true, it upsets many of our old notions. We have thought it desirable to plow under manure, in order to prevent the ammonia from escaping. You claim, I believe, that there is little danger of any loss from spreading manure on the surface, and I suppose you would have us conclude that we make a mistake in plowing it under, as the soil renders it insoluble.”

“It depends a good deal,” said I, “on the character of the soil. A light, sandy soil will not preserve manure like a clay soil. But it is undoubtedly true that our aim in all cases should be to apply manure in such a form and to such a crop as will give us the greatest immediate benefit. Plowing under fresh manure every year for wheat is evidently not the best way to get the greatest benefit from it. But this is not the place to discuss this matter. Let us look at the result of Mr. Lawes’ experiments on wheat the third year:”

Experiments at Rothamsted on the Growth of Wheat, Year after Year, on the same Land.

TABLE III.—MANURES AND PRODUCE; 3RD SEASON, 1845-6. MANURES AND SEED (OLD RED LAMMAS), SOWN AUTUMN, 1845.

Manures Produce

FM Farmyard Manure. A3W Ash from 3 loads (3,888 lbs.) Wheat-straw. LWM Liebig’s Wheat-manure. PG Peruvian Guano. SiP Silicate of Potass.¹ P-A Pearl-ash. S-A Soda-ash. MLS Magnesian Lime-stone. SPL Superphosphate of Lime. B-A Bone-ash. SAc Sulphuric Acid (Sp. gr. 1-7.) MAc Muriatic Acid. SAm Sulphate of Ammonia. MAm Muriate of Ammonia. RC Rape-Cake. Wt/Bu. Weight per Bushel. OC Offal Corn. TC Total Corn. S&C Straw and Chaff. TP Total Produce (Corn and Straw). C Corn. TP Total Produce. OCD Offal Corn to 100 Dressed. C100 Corn to 100 Straw.

P l o t s. Manures per Acre. Produce per Acre, etc. Increase per Acre by Manure.

SPL Dressed corn.

FM A3W LWM PG SiP P-A S-A MLS B-A SAc MAc SAm MAm RC Quantity Wt/Bu. OC TC S&C TP C&S C S&C TP OC 100 C100

Tons. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. Bush. Pks. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs.

0 .. .. .. 336 .. .. .. .. .. .. .. .. .. .. 28 1¾ 62.3 134 1906 2561 4467 699 1048 1747 7.3 74.4

1 .. .. .. .. .. .. .. .. 224 .. .. .. .. .. 22 0¾ 62.6 120 1509 1953 3462 302 440 742 8.1 77.3

2 14 .. .. .. .. .. .. .. .. .. .. .. .. .. 27 0¾ 63.0 113 1826 2454 4280 619 941 1560 6.6 74.4

3 Unmanured. .. .. .. .. .. .. .. .. .. .. .. .. 17 3¾ 63.8 64 1207 1513 2720 .. .. .. 7.4 79.7

4 .. .. .. .. .. .. .. .. 224 .. 224 224 .. .. 25 3¾ 63.5 130 1777 2390 4167 570 877 1447 7.8 74.3

5a{1 ..} Straw Ash. {.. .. .. .. .. .. .. .. .. .. .. .. 19 0½ 63.7 87 1305 1541 2846 98 28 126 .. 84.6

{2 ..}{.. .. .. .. .. .. .. .. .. 224¹ .. .. 27 0 63.0 126 1827 2309 4136 620 796 1416 .. 79.1

5b{1 ..}{.. .. .. .. .. .. .. .. .. .. .. 448 23 2½ 63.4 100 1598 1721 3319 391 208 599 .. 92.8

{2 ..}{.. .. .. .. .. .. .. .. .. 224¹ .. 448 30 0¾ 63.3 165 2076 2901 4977 869 1388 2257 .. 71.6

6a .. .. 448 .. .. .. .. .. .. .. .. .. .. .. 20 1½ 63.7 102 1400 1676 3076 193 163 356 7.0 83.6

6b .. .. 448 .. .. .. .. .. .. .. .. 112 112 .. 29 0¾ 63.5 114 1967 2571 4538 760 1058 1818 5.3 76.5

7a .. .. 448 .. .. .. .. .. .. .. .. .. .. 448 22 3¼ 63.0 97 1534 1968 3502 327 405 732 6.8 77.9

7b .. .. 448 .. .. .. .. .. .. .. .. 112 112 448 31 3 63.4 150 2163 3007 5170 956 1494 2450 7.5 72.6

8a .. .. .. .. .. .. .. .. 224 .. .. .. .. 448 22 3¾ 63.5 101 1549 1963 3512 342 450 792 7.1 78.9

8b .. .. .. .. .. .. .. .. 224 .. .. 112 112 .. 29 0¾ 63.6 132 1988 2575 4563 781 1062 1843 7.2 77.2

9a .. .. .. .. .. .. .. .. .. .. .. .. .. 448 23 2¾ 63.0 122 1614 2033 3647 407 520 927 7.9 79.4

9b .. .. .. .. .. .. .. .. .. .. .. 224 .. 448 28 3½ 63.3 114 1942 2603 4545 735 1090 1825 7.0 74.6

10a .. .. .. .. .. .. .. .. .. .. .. 224 .. .. 27 1½ 63.6 109 1850 2244 4094 643 731 1374 6.4 82.4

10b Unmanured. .. .. .. .. .. .. .. .. .. .. .. .. 17 2½ 63.8 92 1216 1455 2671 9 -58 -49 7.8 83.6

11a .. .. .. .. .. .. .. .. 224 224 .. .. .. 448 23 1¾ 63.3 145 1628 2133 3761 421 620 1041 9.8 76.3

11b .. .. .. .. .. .. .. .. 224 224 .. 112 112 .. 30 0¼ 63.2 155 2055 2715 4770 848 1202 2050 6.1 75.7

12a .. .. .. .. .. .. 180 .. 224 224 .. .. .. 448 24 1½ 63.0 125 1661 2163 3824 454 650 1104 7.9 76.8

12b .. .. .. .. .. .. 180 .. 224 224 .. 112 112 .. 28 2¾ 63.4 136 1955 2554 4509 748 1041 1789 7.4 76.5

13a .. .. .. .. .. 200 .. .. 224 224 .. .. .. 448 24 0 63.5 136 1660 2327 3987 453 814 1267 9.1 71.3

13b .. .. .. .. .. 200 .. .. 224 224 .. 112 112 .. 29 1¾ 63.2 138 1998 2755 4753 791 1242 2033 7.3 72.5

14a .. .. .. .. .. .. .. 84 224 224 .. .. .. 448 23 2½ 63.0 117 1605 2031 3636 398 518 916 7.7 79.0

14b .. .. .. .. .. .. .. 84 224 224 .. 112 112 .. 26 2½ 63.4 124 1812 2534 4356 605 1021 1626 7.4 71.5

15a .. .. .. .. .. .. .. .. 224 .. 224 224 .. 448 31 1¾ 62.5 147 2112 2936 5048 905 1423 2328 7.5 71.9

15b .. .. .. .. 224 .. .. .. 224 .. 224 224 .. 448 27 2¾ 63.0 117 1861 2513 4374 654 1000 1654 5.9 74.0

16a .. .. .. .. .. 67 60 84 224 224 .. .. .. 448 23 3 62.5 108 1592 2967 3659 385 554 939 7.0 77.0

16b .. .. .. .. .. 67 60 84 224 224 .. 224 .. 448 30 1 62.7 122 2019 2836 4855 812 1323 2135 6.6 71.2

17a .. .. .. .. .. 67 60 84 224 224 .. 112 11 448 33 2¾ 62.8 129 2241 3278 5519 1034 1765 2799 5.8 68.3

17b .. .. .. .. .. 67 60 84 224 224 .. 224 .. .. 30 2 63.0 113 2034 2784 4818 827 1271 2098 5.9 73.0

18a .. .. .. .. .. 67 60 84 224 224 .. 112 11 .. 31 0 62.8 103 2048 2838 4886 841 1325 2166 5.1 72.2

18b .. .. .. .. .. 67 60 84 224 224 .. .. .. .. 21 1 62.0 157 1474 1893 3367 267 380 647 6.6 77.1

19 .. .. .. .. .. .. .. .. 112 .. 112 112 .. 448 28 3 62.0 107 1889 2425 4314 682 912 1594 5.8 77.9

20} Mixture of the residue of most of the other manures. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ..

21}.. .. .. .. .. .. .. .. .. .. .. .. .. .. ..

22}.. .. .. .. .. .. .. .. .. .. .. .. .. .. ..

This year, the seed and manures were sown in the autumn. And I want the Deacon to look at plot 0. 3 cwt. of Peruvian guano here gives an increase of 10½ bushels of wheat, and 1,948 lbs. of straw per acre. This will pay well, even on the wheat alone. But in addition to this, we may expect, in our ordinary rotation of crops, a far better crop of clover where the guano was used.

In regard to some of the results this year, Messrs. Lawes and Gilbert have the following concise and interesting remarks:

“At this third experimental harvest, we have on the continuously unmanured plot, namely, No. 3, not quite 18 bushels of dressed corn, as the normal produce of the season; and by its side we have on plot 10b—comprising one-half of the plot 10 of the previous years, and so highly manured by ammoniacal salts in 1845, but now unmanured—rather more than 17½ bushels. The near approach, again, to identity of result from the two unmanured plots, at once gives confidence in the accuracy of the experiments, and shows us how effectually the preceding crop had, in a practical point of view, reduced the plots, previously so differently circumstanced both as to manure and produce, to something like an uniform standard as regards their grain-producing qualities.

“Plot 2 has, as before, 14 tons of farm-yard manure, and the produce is 27¼ bushels, or between 9 and 10 bushels more than without manure of any kind.

“On plot 10a, which in the previous year gave by ammoniacal salts alone, a produce equal to that of the farm-yard manure, we have again a similar result: for two cwts. of sulphate of ammonia has now given 1,850 lbs. of total corn, instead of 1,826 lbs., which is the produce on plot 2. The straw of the latter, is, however, slightly heavier than that by the ammoniacal salt.

“Again, plot 5a, which was in the previous season unmanured, was now subdivided: on one-half of it (namely, 5a¹) we have the ashes of wheat-straw alone, by which there is an increase of rather more than one bushel per acre of dressed corn; on the other half (or 5a²) we have, besides the straw-ashes, two cwts. of sulphate of ammonia put on as a top-dressing: two cwts. of sulphate of ammonia have, in this case, only increased the produce beyond that of 5a¹ by 7⅞ bushels of corn and 768 lbs. of straw, instead of by 9¾ bushels of corn and 789 lbs. of straw, which was the increase obtained by the same amount of ammoniacal salt on 10a, as compared with 10b.

“It will be observed, however, that in the former case the ammoniacal salts were top-dressed, but in the latter they were drilled at the time of sowing the seed; and it will be remembered that in 1845 the result was better as to corn on plot 9, where the salts were sown earlier, than on plot 10, where the top-dressing extended far into the spring. We have had several direct instances of this kind in our experience, and we would give it as a suggestion, in most cases applicable, that manures for wheat, and especially ammoniacal ones, should be applied before or at the time the seed is sown; for, although the apparent luxuriance of the crop is greater, and the produce of straw really heavier, by spring rather than autumn sowings of Peruvian guano and other ammoniacal manures, yet we believe that that of the corn will not be increased in an equivalent degree. Indeed, the success of the crop undoubtedly depends very materially on the progress of the underground growth during the winter months; and this again, other things being equal, upon the quantity of available nitrogenous constituents within the soil, without a liberal provision of which, the range of the fibrous feeders of the plant will not be such, as to take up the minerals which the soil is competent to supply, and in such quantity as will be required during the after progress of the plant for its healthy and favorable growth.”

These remarks are very suggestive and deserve special attention.

“The next result to be noticed,” continue Messrs. Lawes and Gilbert, “is that obtained on plot 6, now also divided into two equal portions designated respectively 6a and 6b. Plot No. 6 had for the crop of 1844, superphosphate of lime and the phosphate of magnesia manure, and for that of 1845, superphosphate of lime, rape-cake, and ammoniacal salts. For this, the third season, it was devoted to the trial of the wheat-manure manufactured under the sanction of Professor Liebig, and patented in this country.

“Upon plots 6a, four cwts. per acre of the patent wheat-manure were used, which gave 20¼ bushels, or rather more than two bushels beyond the produce of the unmanured plot; but as the manure contained, besides the minerals peculiar to it, some nitrogenous compounds, giving off a very perceptible odor of ammonia, some, at least, of the increase would be due to that substance. On plot 6b, however, the further addition of one cwt. each of sulphate and muriate of ammonia to this so-called ‘Mineral Manure,’ gives a produce of 29¼ bushels. In other words, the addition of ammoniacal salt, to Liebig’s mineral manure has increased the produce by very nearly 9 bushels per acre beyond that of the mineral manure alone, whilst the increase obtained over the unmanured plot, by 14 tons of farm-yard manure, was only 9¼ bushels!

The following table gives the results of the experiments the fourth year, 1846-7.

Experiments at Rothamsted on the Growth of Wheat, Year after Year, on the same Land.

TABLE IV.—MANURES AND PRODUCE; 4TH SEASON, 1846-7. MANURES AND SEED (OLD RED LAMMAS), SOWN END OF OCTOBER, 1846.

Manures Produce

FM Farm-yard Manure. PG Peruvian Guano. SPL Superphosphate of Lime. B-A Bone-ash. SAc Sulphuric Acid (Sp. gr. 1-7.) MAc Muriatic Acid. SAm Sulphate of Ammonia. MAm Muriate of Ammonia. R Rice. Wt/Bu. Weight per Bushel. OC Offal Corn. TC Total Corn. S&C Straw and Chaff. TP/C&S Total Produce (Corn and Straw.) C Corn. TP Total Produce. OCD Offal Corn to 100 Dressed. C100 Corn to 100 Straw.

P l o t s. Manures per Acre. Produce per Acre, etc. Increase per Acre by Manure.

SPL Dressed corn.

FM PG B-A SAc MAc SAm MAm R Quantity Wt/Bu. OC TC S&C TP C&S C S&C TP OC 100 C100

Tons. lbs. lbs. lbs. lbs. lbs. lbs. lbs. Bush. Pks. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs.

0 .. 500 .. .. .. .. .. .. 30 2¾ 61.1 156 2031 3277 5308 908 1375 2283 8.2 61.9

1 .. .. 200 .. 200 350 50 .. 32 1 61.2 147 2119 3735 5854 996 1833 2829 7.2 56.7

2 14 .. .. .. .. .. .. .. 29 3¾ 62.3 117 1981 3628 5609 858 1726 2584 6.2 54.6

3 Unmanured. .. .. .. .. .. .. 16 3½ 61.0 95 1123 1902 3025 .. .. .. 8.9 59.0

4 .. .. 200 .. 200 300 .. .. 27 1¾ 61.9 82 1780 2948 4728 657 1046 1703 4.7 60.3

5a .. .. 200 200 .. 150 150 .. 29 0 61.8 130 1921 3412 5333 798 1510 2309 7.1 56.3

5b .. .. 200 200 .. 150 150 500 32 2 61.4 136 2132 3721 5853 1009 1819 2827 6.6 57.2

6a .. .. .. .. .. 150 150 .. 24 3¼ 62.1 122 1663 2786 4449 540 884 1124 7.8 59.6

6b .. .. .. .. .. 150 150 .. 24 1¾ 61.6 127 1632 2803 4435 509 901 1410 8.2 58.2

7a .. .. .. .. .. 150 150 .. 27 3¼ 61.7 118 1834 3151 4985 711 1249 1960 6.8 58.2

7b .. .. .. .. .. 150 150 .. 25 1¼ 61.5 125 1682 2953 4635 559 1051 1610 7.9 56.9

8a .. .. 200 200 .. 150 150 500 32 1¾ 62.1 102 2115 3683 5798 992 1781 2773 5.5 57.4

8b .. .. 200 200 .. 200 200 .. 30 3 61.7 123 2020 3720 5740 897 1818 2715 6.5 54.3

9a{1 .. .. .. .. .. .. .. 2240 22 3 62.5 .. 1477 2506 3983 228 604 .. .. 53.9

{2 .. .. .. .. .. 150 150 .. 26 2 61.0 .. 1755 3052 4807 632 1150 .. .. 57.5

9b .. .. .. .. .. 150 150 .. 26 0 61.3 123 1717 2858 4575 594 956 1550 .. 60.1

10a .. .. .. .. .. 150 150 .. 25 3 61.5 118 1702 2891 4593 579 989 1568 7.3 58.8

10b .. .. .. .. .. 150 150 .. 25 2¾ 61.2 133 1705 2874 4579 582 972 1554 8.2 59.3

11a .. .. 100 100 .. 150 150 .. 30 3½ 61.6 142 2044 3517 5561 921 1615 2536 6.3 59.5

11b .. .. 100 100 .. 150 150 .. 29 1¾ 61.8 123 1941 3203 5144 818 1301 2119 6.7 60.6

12a .. .. 100 100 .. 150 150 .. 29 2 62.0 124 1953 3452 5405 830 1550 2380 6.6 57.1

12b .. .. 100 100 .. 150 150 .. 27 0½ 61.8 121 1796 3124 4920 673 1222 1895 7.1 57.4

13a .. .. 100 100 .. 150 150 .. 20 2½ 62.5 108 1959 3306 5265 836 1404 2240 5.5 57.3

13b .. .. 100 100 .. 150 150 .. 27 1¼ 62.3 96 1801 3171 4972 678 1269 1947 5.3 56.7

14a .. .. 100 100 .. 150 150 .. 28 0¾ 62.8 175 1944 3362 5306 821 1460 2281 9.7 59.5

14b .. .. 100 100 .. 150 150 .. 26 3¾ 62.8 166 1856 3006 4862 733 1104 1837 9.8 61.7

15a .. .. 200 .. 200 300 .. 500 32 3 63.0 151 2214 3876 6090 1091 1974 3065 7.2 57.1

15b .. .. 200 .. 200 300 .. 500 32 0 62.6 137 2140 3617 5757 1017 1715 2732 6.6 59.1

16a .. .. 100 100 .. 150 150 .. 29 1¼ 62.3 132 1959 3417 5376 836 1515 2351 6.9 57.3

16b .. .. 100 100 .. 150 150 .. 34 2¼ 62.6 119 2283 4012 6295 1160 2110 3270 5.2 56.9

17a .. .. 100 100 .. 150 150 .. 33 3 62.3 119 2222 4027 6249 1099 2125 3224 5.6 55.1

17b .. .. 100 100 .. 200 200 .. 35 1¼ 62.0 117 2314 4261 6575 1191 2359 3550 6.4 54.3

18a .. .. 100 100 .. 150 150 .. 32 0¾ 62.7 142 2160 3852 6012 1037 1950 2987 6.9 56.0

18b .. .. 100 100 .. 150 150 .. 29 1½ 62.9 181 2029 4164 6193 906 2262 3168 9.7 48.7

19 .. .. 100 .. 100 300 .. 500 32 3 62.8 140 2195 4202 6397 1072 2300 3372 6.7 52.2

20 Unmanured. .. .. .. .. .. .. 20 0¾ 62.5 70 1332 2074 3406 209 172 381 4.9 64.2

21} Mixture of the residue of most of the other manures. .. .. .. .. .. .. .. .. .. .. .. ..

22}

Here again, I want the Deacon to look at plot 0, where 500 lbs. Peruvian guano, sown in October, gives an increase of nearly 14 bushels of dressed wheat and 1,375 lbs. of straw per acre. On plot 2, where 14 tons of barn-yard manure have now been applied four years in succession (56 tons in all), there is a little more straw, but not quite so much grain, as from the 500 lbs. of guano.

“But will the guano,” said the Deacon, “be as lasting as the manure?”

“Not for wheat,” said I. “But if you seed the wheat down with clover, as would be the case in this section, we should get considerable benefit, probably, from the guano. If wheat was sown after the wheat, the guano applied the previous season would do little good on the second crop of wheat. And yet it is a matter of fact that there would be a considerable proportion of the guano left in the soil. The wheat cannot take it up. But the clover can. And we all know that if we can grow good crops of clover, plowing it under, or feeding it out on the land, or making it into hay and saving the manure obtained from it, we shall thus be enabled to raise good crops of wheat, barley, oats, potatoes, and corn, and in this sense guano is a ‘lasting’ manure.”

“Barnyard-manure,” said the Doctor, “is altogether too ‘lasting.’ Here we have had 56 tons of manure on an acre of land in four years, and yet an acre dressed with 500 lbs. of guano produces just as good a crop. The manure contains far more plant-food, of all kinds, than the guano, but it is so ‘lasting’ that it does not do half as much good as its composition would lead us to expect. Its ‘lasting’ properties are a decided objection, rather than an advantage. If we could make it less lasting—in other words, if we could make it act quicker, it would produce a greater effect, and possess a greater value. In proportion to its constituents, the barn-yard manure is far cheaper than the guano, but it has a less beneficial effect, because these constituents are not more completely decomposed and rendered available.”

“That,” said I, “opens up a very important question. We have more real value in manure than most of us are as yet able to bring out and turn to good account. The sandy-land farmer has an advantage over the clay-land farmer in this respect. The latter has a naturally richer soil, but it costs him more to work it, and manure does not act so rapidly. The clay-land farmer should use his best endeavors to decompose his manure.”

“Yes,” said the Doctor, “and, like John Johnston, he will probably find it to his advantage to use it largely as a top-dressing on the surface. Exposing manure to the atmosphere, spread out on the land for several months, and harrowing it occasionally, will do much to render its constituents available. But let us return to Mr. Lawes’ wonderful experiments.”

“On eight plots,” said I, “300 lbs. of ammonia-salts were used without any other manures, and the average yield on these eight plots was nearly 26 bushels per acre, or an average increase of 9 bushels per acre. The same amount of ammonia-salts, with the addition of superphosphate of lime, gave an increase of 13 bushels per acre. 400 lbs. ammonia salts, with superphosphate of lime, gave an increase of nearly 16 bushels per acre, or three bushels per acre more than where 14 tons of barn-yard manure had been used four years in succession.

“I hope, after this, the Deacon will forgive me for dwelling on the value of available nitrogen or ammonia as a manure for wheat.”

“I see,” said the Deacon, “that ground rice was used this year for manure; and in 1845, tapioca was also used as a manure. The Connecticut Tobacco growers a few years since used corn-meal for manure, and you thought it a great waste of good food.”

I think so still. But we will not discuss the matter now. Mr. Lawes wanted to ascertain whether carbonaceous matter was needed by the growing wheat-plants, or whether they could get all they needed from the soil and the atmosphere. The enormous quantities of carbonaceous matter supplied by the barn-yard manure, it is quite evident, are of little value as a manure for wheat. And the rice seems to have done very little more good than we should expect from the 22 lbs. of nitrogen which it contained. The large quantity of carbonaceous matter evidently did little good. Available carbonaceous matter, such as starch, sugar, and oil, was intended as food for man and beast—not as food for wheat or tobacco.

The following table gives the results of the experiments the fifth year, 1847-8.

Experiments at Rothamsted on the Growth of Wheat, Year after Year, on the same Land.

TABLE V.—MANURES AND PRODUCE; 5TH SEASON, 1847-8. MANURES AND SEED (OLD RED LAMMAS) SOWN AUTUMN, 1847.

Manures Produce

FM Farm-yard Manure. P-A Pearl-ash. S-A Soda-ash. SMg Sulphate of Magnesia. SPL Superphosphate of Lime. B-A Bone-ash. SAc Sulphuric Acid (Sp. gr. 1.7.) MAc Muriatic Acid. SAm Sulphate of Ammonia. MAm Muriate of Ammonia. RC Rape-Cake. Wt/Bu. Weight per Bushel. OC Offal Corn. TC Total Corn. S&C Straw and Chaff. TP/C&S Total Produce (Corn and Straw.) C Corn. TP Total Produce. OCD Offal Corn to 100 Dressed. C100 Corn to 100 Straw.

P l o t s. Manures per Acre. Produce per Acre, etc. Increase per Acre by Manure.

SPL Dressed corn.

FM P-A S-A SMg SPL B-A SAc MAc SAm MAm RC Quantity Wt/Bu. OC TC S&C TP C&S C S&C TP OC 100 C100

Tons. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. Bush. Pks. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs.

0 .. .. .. .. 2240 .. .. .. .. .. .. 19 0¾ 53.4 138 1259 2074 3333 307 362 669 13.4 60.7

1 .. .. .. .. .. .. .. .. .. .. .. 16 0¾ 59.6 160 1124 1735 2859 172 23 195 16.3 64.7

2 14 .. .. .. .. .. .. .. .. .. .. 23 2¾ 58.2 210 1705 3041 4746 753 1329 2082 13.8 56.0

3 Unmanured. .. .. .. .. .. .. .. .. .. 14 3 57.3 106 952 1712 2664 .. .. .. 12.1 55.6

4 .. .. .. .. .. 200 .. 200 300 .. .. 24 0½ 58.5 172 1583 2713 4296 631 1001 1632 12.0 58.3

5a .. 300 200 100 .. 200 150 .. 250 250 .. 29 3½ 59.2 144 1911 3266 5177 959 1554 2513 7.9 58.5

5b .. 300 200 100 .. 200 150 .. 200 200 500 39 3½ 59.1 107 1932 3533 5465 980 1821 2801 5.8 57.5

6a .. .. .. .. .. 400 300 .. 200 200 .. 24 3¼ 58.8 214 1672 2878 4550 720 1166 1886 14.6 58.0

6b .. .. .. .. .. 200 150 .. 200 200 .. 26 3 56.9 216 1737 2968 4705 785 1256 2041 14.0 58.5

7a .. .. .. .. .. 400 300 .. 150 150 500 30 3¼ 59.4 106 1936 3088 5024 984 1376 2360 5.7 62.6

7b .. .. .. .. .. 200 150 .. 150 150 500 29 3¼ 59.6 187 1963 3413 5376 1011 1701 2712 10.3 57.5

8a .. 300 200 100 .. 200 150 .. .. .. .. 19 3 56.2 154 1263 2317 3580 311 605 916 13.6 54.5

8b .. 300 200 100 .. 200 150 .. .. .. .. 19 0¾ 59.4 127 1267 2148 3415 315 436 751 11.1 58.8

9a .. .. .. .. .. 200 150 .. .. .. .. 18 2½ 56.7 125 1181 1945 3126 229 233 462 11.6 60.7

9b .. .. .. .. .. 200 150 .. 150 150 .. 25 0¼ 53.3 208 1669 2918 4587 717 1206 1923 13.9 57.1

10a .. .. .. .. .. .. .. .. 150 150 .. 19 1 58.1 215 1334 2367 3701 382 655 1037 19.0 56.3

10b .. 300 200 100 .. 200 150 .. 150 150 .. 25 0¼ 57.8 155 1604 2926 4530 652 1214 1866 10.6 54.8

11a .. .. .. .. .. 200 150 .. 150 150 500 29 1½ 59.6 233 1984 3274 5258 1032 1562 2594 13.1 60.6

11b .. .. .. .. .. 200 150 .. 200 200 .. 24 3 57.9 207 1641 2898 4539 689 1186 1875 14.1 56.4

12a .. 300 .. .. .. 200 150 .. 150 150 500 29 3 59.3 174 1938 3390 5328 986 1678 2664 9.3 57.2

12b .. 300 .. .. .. 200 150 .. 200 200 .. 26 0¾ 59.2 167 1717 2880 4597 765 1168 1933 10.7 59.6

13a .. 300 .. .. .. 200 150 .. 150 150 500 29 1½ 57.9 253 1955 3290 5245 1003 1578 2581 14.7 59.4

13b .. 300 .. .. .. 200 150 .. 200 200 .. 25 3¼ 58.4 224 1730 3072 4802 778 1360 2138 14.6 56.3

14a .. 300 .. .. .. 200 150 .. 150 150 500 28 0¼ 58.8 184 1834 3257 5091 882 1545 2427 11.1 56.3

14b .. 300 .. .. .. 200 150 .. 200 200 .. 25 2½ 58.5 227 1726 2897 4623 774 1185 1959 15.1 59.5

15a .. 300 200 100 .. 200 .. 200 300 .. .. 22 3½ 58.1 242 1571 2937 4508 619 1225 1844 18.1 53.4

15b .. 300 200 100 .. 200 .. 200 300 .. .. 24 2¾ 56.9 202 1607 3016 4623 655 1304 1959 14.1 53.2

16a .. 300 200 100 .. 200 150 .. 150 150 500 29 3¼ 60.0 184 1973 3115 5088 1021 1403 2424 10.2 63.3

16b .. 300 200 100 .. 200 150 .. 150 150 500 30 1¾ 58.4 171 1948 3380 5328 996 1668 2664 9.4 57.6

17a .. 300 200 100 .. 200 150 .. 200 200 .. 27 2½ 59.7 285 1933 3296 5229 981 1584 2565 17.0 58.6

17b .. 300 200 100 .. 200 150 .. 200 200 .. 28 3½ 59.7 222 1946 3324 5270 994 1612 2606 12.6 58.5

18a .. 300 200 100 .. 200 150 .. 150 150 .. 26 3 59.2 150 1734 2935 4669 782 1223 2005 9.2 59.0

18b .. 300 200 100 .. 200 150 .. 150 150 .. 26 2¾ 59.6 215 1804 3056 4860 852 1344 2196 13.3 58.7

19 .. .. .. .. .. 200 .. 200 300 .. 500 29 1¾ 56.2 185 1838 3295 5133 886 1583 2469 10.4 55.7

20 Unmanured. .. .. .. .. .. .. .. .. .. 16 0½ 58.3 111 1050 1721 2771 98 9 107 11.3 61.0

21} .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ..

22}

This season was considered unfavorable for wheat. The continuously unmanured plot produced 14¾ bushels, and the plot receiving 14 tons of barn yard manure, 25¾ bushels per acre nearly.

300 lbs. of ammonia-salts alone on plot 10a, gave 19¼ bushels per acre, while the same quantity of ammonia, with superphosphate in addition, gave, on plot 9b, 25 bushels per acre.

The addition to the above manures of 300 lbs. of potash, 200 lbs. soda, and 100 lbs. sulphate of magnesia, on plot 10b, gave precisely the same yield per acre as the ammonia and the superphosphate alone. The potash, soda, and magnesia, therefore, did no good.

400 lbs. of ammonia-salts, with superphosphate, potash, etc., gave, on plot 17b, nearly 29 bushels per acre, or 3½ bushels more than the plot which has now received 70 tons of barn-yard manure in five successive years.

“I see that, on plot 0,” said the Deacon, “one ton of superphosphate was used per acre, and it gave only half a bushel per acre more than 350 lbs. on 9a.”

“This proves,” said I, “that an excessive dose of superphosphate will do no harm. I am not sure that 100 lbs. of a good superphosphate drilled in with the seed, would not have done as much good as a ton per acre.”

“You say,” remarked the Deacon, “that the season was unfavorable for wheat. And yet the no-manure plot produced nearly 15 bushels of wheat per acre.”

“That is all true,” said I, “and yet the season was undoubtedly an unfavorable one. This is shown not only in the less yield, but in the inferior quality of the grain. The ‘dressed corn’ on the no-manure plot this year only weighed 57⅓ lbs. per bushel, while last year it weighed 61 lbs. per bushel.”

“By the way,” said the Doctor, “what do Messrs. Lawes and Gilbert mean by ‘dressed corn’?”

“By ‘corn,’” said I, “they mean wheat; and by ‘dressed corn’ they mean wheat that has been run through a fanning-mill until all the light and shrunken grain is blown or sieved out. In other words, ‘dressed corn’ is wheat carefully cleaned for market. The English farmers take more pains in cleaning their grain than we do. And this ‘dressed corn’ was as clean as a good fanning-mill could make it. You will observe that there was more ‘offal corn’ this year than last. This also indicates an unfavorable season.”

“It would have been very interesting,” said the Doctor, “if Messrs. Lawes and Gilbert had analyzed the wheat produced by the different manures, so that we might have known something in regard to the quality of the flour as influenced by the use of different fertilizers.”

“They did that very thing,” said I, “and not only that, but they made the wheat grown on different plots, into flour, and ascertained the yield of flour from a given weight of wheat, and the amount of bran, middlings, etc., etc. They obtained some very interesting and important results. I was there at the time. But this is not the place to discuss the question. I am often amused, however, at the remarks we often hear in regard to the inferior quality of our wheat as compared to what it was when the country was new. Many seem to think that ‘there is something lacking in the soil’—some say potash, and some phosphates, and some this, and some that. I believe nothing of the kind. Depend upon it, the variety of the wheat and the soil and season have much more to do with the quality or strength of the flour, than the chemical composition of the manures applied to the land.”

“At any rate,” said the Doctor, “we may be satisfied that anything that will produce a vigorous, healthy growth of wheat is favorable to quality. We may use manures in excess, and thus produce over-luxuriance and an unhealthy growth, and have poor, shrunken grain. In this case, it is not the use, but the abuse of the manure that does the mischief. We must not manure higher than the season will bear. As yet, this question rarely troubles us. Hitherto, as a rule, our seasons are better than our farming. It may not always be so. We may find the liberal use of manure so profitable that we shall occasionally use it in excess. At present, however, the tendency is all the other way. We have more grain of inferior quality from lack of fertility than from an excess of plant-food.”

“That may be true,” said I, “but we have more poor, inferior wheat from lack of draining and good culture, than from lack of plant-food. Red-root, thistles, cockle, and chess, have done more to injure the reputation of ‘Genesee Flour,’ than any other one thing, and I should like to hear more said about thorough cultivation, and the destruction of weeds, and less about soil exhaustion.”

The following table shows the results of the experiments the sixth year, 1848-9.

Experiments at Rothamsted on the Growth of Wheat, Year after Year, on the same Land.

TABLE VI.—MANURES AND PRODUCE; 6TH SEASON, 1848-9. MANURES AND SEED (RED CLUSTER), SOWN AUTUMN, 1848.

Manures Produce

FM Farm-yard Manure. P-A Pearl-ash. S-A Soda-ash. SMg Sulphate of Magnesia. SPL Superphosphate of Lime. B-A Bone-ash. SAc Sulphuric Acid. (Sp. gr. 1.7) MAc Muriatic Acid. SAm Sulphate of Ammonia. MAm Muriate of Ammonia. RC Rape-cake. Wt/Bu. Weight per Bushel. OC Offal Corn. TC Total Corn. S&C Straw and Chaff. TP/C&S Total Produce (Corn and Straw.) C Corn. TP Total Produce. OCD Offal Corn to 100 Dressed. C100 Corn to 100 Straw.

P l o t s. Manures per Acre. Produce per Acre, etc. Increase per Acre by Manure.

SPL Dressed corn.

FM P-A S-A SMg B-A SAc MAc SAm MAm RC Quantity Wt/Bu. OC TC S&C TP C&S C S&C TP OC 100 C100

Tons. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. Bush. Pks. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs.

0 .. .. .. .. 600 450 .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ..

1 .. 600 400 200 .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ..

2 14 .. .. .. .. .. .. .. .. .. 31 0 63.8 107 2068 3029 5097 839 1415 2254 4.7 68.3

3 Unmanured. .. .. .. .. .. .. .. .. 19 1 61.4 47 1229 1614 2843 .. .. .. 3.9 76.1

4 .. .. .. .. 200 .. 200 300 .. .. 30 0 63.0 110 2063 2645 4708 834 1031 1865 5.6 78.0

5a .. 300 200 100 200 150 .. 250 250 .. 37 1¼ 63.1 89 2446 3589 6035 1217 1975 3192 3.7 68.1

5b .. 300 200 100 200 150 .. 200 200 500 39 3½ 63.4 97 2651 3824 6475 1422 2210 3632 5.0 69.3

6a .. 300 200 100 200 150 .. 200 200 .. 36 1½ 63.0 117 2410 3072 5482 1181 1458 2639 5.1 78.4

6b .. 300 200 100 200 150 .. 200 200 .. 37 3¾ 63.0 94 2484 3516 6000 1255 1902 3157 3.9 70.6

7a .. 300 200 100 200 150 .. 200 200 .. 38 2¼ 63.1 137 2576 3584 6160 1347 1970 3317 5.6 71.9

7b .. 300 200 100 200 150 .. 200 200 .. 37 3¾ 62.9 141 2531 3396 5927 1302 1782 3084 5.9 74.5

8a Unmanured. .. .. .. .. .. .. .. .. 22 3 61.7 76 1481 1815 3296 252 201 453 5.3 81.6

8b .. .. .. .. .. .. .. .. .. 2000 31 2½ 63.0 85 2080 3166 5246 851 1552 2403 4.3 65.7

9a .. .. .. .. .. .. .. .. .. 2000 30 2¾ 62.8 111 2035 2683 4718 806 1069 1875 5.8 75.8

9b Unmanured. .. .. .. .. .. .. .. .. 22 1½ 62.3 80 1475 1810 3285 246 196 432 5.7 81.5

10a .. .. .. .. .. .. .. 200 200 .. 32 2¼ 62.3 112 2141 2851 4992 912 1237 2149 5.5 75.1

10b .. .. .. .. .. .. .. 200 200 .. 32 1¼ 63.3 110 2157 2960 5117 928 1346 2274 5.3 72.9

11a .. .. .. .. 200 150 .. 200 200 .. 35 0½ 62.6 121 2317 2892 5209 1088 1278 2366 5.6 80.1

11b .. .. .. .. 200 150 .. 200 200 .. 32 1¼ 63.0 112 2149 2942 5091 920 1328 2248 5.5 73.0

12a .. 300 .. .. 200 150 .. 200 200 .. 35 3¼ 64.3 93 2396 3371 5767 1167 1757 2924 4.1 71.1

12b .. 300 .. .. 200 150 .. 200 200 .. 34 1¼ 64.3 71 2277 3300 5577 1048 1687 2735 3.2 69.0

13a .. 300 .. .. 200 150 .. 200 200 .. 34 3¾ 64.1 101 2340 3236 5576 1111 1622 2733 4.5 72.3

13b .. 300 .. .. 200 150 .. 200 200 .. 34 2¼ 64.1 129 2346 3246 5592 1117 1632 2749 5.8 72.3

14a .. 300 .. .. 200 150 .. 200 200 .. 34 1½ 64.3 56 2266 3211 5477 1037 1597 2634 2.5 70.6

14b .. 300 .. .. 200 150 .. 200 200 .. 31 1¼ 64.3 112 2123 3218 5341 894 1604 2498 5.5 66.0

15a .. 300 200 100 200 .. 200 300 .. .. 31 3¼ 64.2 65 2109 3038 5147 880 1424 2304 3.2 69.4

15b .. 300 200 100 200 .. 200 300 .. 500 30 0¾ 64.1 68 2005 3262 5267 776 1648 2424 3.5 61.5

16a .. 300 200 100 200 150 .. 200 200 .. 33 1½ 64.5 101 2254 3384 5638 1025 1770 2795 4.7 66.6

16b .. 300 200 100 200 150 .. 200 200 .. 33 3¾ 64.6 75 2268 3559 5827 1039 1945 2984 3.4 63.7

17a .. 300 200 100 200 150 .. 200 200 .. 34 1 64.3 111 2316 3891 6207 1087 2277 3364 5.1 59.4

17b .. 300 200 100 200 150 .. 200 200 .. 33 1½ 64.4 112 2259 3858 6117 1030 2244 3274 5.2 58.5

18a .. 300 200 100 200 150 .. 200 200 .. 32 1¼ 64.0 93 2163 3592 5755 934 1978 2912 4.5 60.2

18b .. 300 200 100 200 150 .. 200 200 .. 33 2¼ 64.0 95 2243 3779 6022 1014 2165 3179 4.4 59.3

19 .. .. .. .. 200 .. 200 300 .. 500 29 2¼ 63.9 102 1994 3270 5264 765 1656 2421 5.4 61.0

20 Unmanured. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ..

21} Mixture of the residue of most of the other manures. .. .. .. .. .. .. .. .. .. .. .. .. ..

22}

“This was my last year at Rothamsted,” said I, “and I feel a peculiar interest in looking over the results after such a lapse of time. When this crop was growing, my father, a good practical farmer, but with little faith in chemical manures, paid me a visit. We went to the experimental wheat-field. The first two plots, 0 and 1, had been dressed, the one with superphosphate, the other with potash, soda, and magnesia. My father did not seem much impressed with this kind of chemical manuring. Stepping to the next plot, where 14 tons of barn-yard manure had been used, he remarked, “this is good, what have you here?”

“Never mind,” said I, “we have better crops farther on.”

The next plot, No. 3, was the one continuously unmanured. “I can beat this myself,” said he, and passed on to the next. “This is better,” said he, “what have you here?”

“Superphosphate and sulphate of ammonia.”

“Well, it is a good crop, and the straw is bright and stiff.”—It turned out 30 bushels per acre, 63 lbs. to the bushel.

The next six plots had received very heavy dressings of ammonia-salts, with superphosphate, potash, soda, and magnesia. He examined them with the greatest interest. “What have you here?” he asked, while he was examining 5a, which afterwards turned out 37¼ bushels per acre. —“Potash, soda, epsom-salts, superphosphate, and ammonia—but it is the ammonia that does the good.”

He passed to the next plot, and was very enthusiastic over it. “What have you here?” —“Rape-cake and ammonia,” said I. —“It is a grand crop,” said he, and after examining it with great interest, he passed to the next, 6a. —“What have you here?” —“Ammonia,” said I; and at 6b he asked the same question, and I replied “ammonia.” At 7a, the same question and the same answer. Standing between 7b and 8a, he was of course struck with the difference in the crop; 8a was left this year without any manure, and though it had received a liberal supply of mineral manures the year before, and minerals and ammonia-salts, and rape-cake, the year previous, it only produced this year, 3½ bushels more than the plot continuously unmanured. The contrast between the wheat on this plot and the next one might well interest a practical farmer. There was over 15 bushels per acre more wheat on the one plot than on the other, and 1,581 lbs. more straw.

Passing to the next plot, he exclaimed “this is better, but not so good as some that we have passed.” —“It has had a heavy dressing of rape-cake,” said I, “equal to about 100 lbs. of ammonia per acre, and the next plot was manured this year in the same way. The only difference being that one had superphosphate and potash, soda, and magnesia, the year before, while the other had superphosphate alone.” It turned out, as you see from the table, that the potash, etc., only gave half a bushel more wheat per acre the year it was used, and this year, with 2,000 lbs. of rape-cake on each plot, there is only a bushel per acre in favor of the potash, soda, and magnesia.

The next plot, 9b, was also unmanured and was passed by my father without comment. “Ah,” said he, on coming to the two next plots, 10a and 10b, “this is better, what have you here?” —“Nothing but ammonia,” said I, “and I wish you would tell me which is the best of the two? Last year 10b had a heavy dressing of minerals and superphosphate with ammonia, and 10a the same quantity of ammonia alone, without superphosphate or other mineral manures. And this year both plots have had a dressing of 400 lbs. each of ammonia-salts. Now, which is the best—the plot that had superphosphate and minerals last year, or the one without?” —“Well,” said he, “I can’t see any difference. Both are good crops.”

You will see from the table, that the plot which had the superphosphate, potash, etc., the year before, gives a peck less wheat this year than the other plot which had none. Practically, the yield is the same. There is an increase of 13 bushels of wheat per acre—and this increase is clearly due to the ammonia-salts alone.

The next plot was also a splendid crop.

“What have you here?”

“Superphosphate and ammonia.”

This plot (11a), turned out 35 bushels per acre. The next plot, with phosphates and ammonia, was nearly as good. The next plot, with potash, phosphates, and ammonia, equally good, but no better than 11a. There was little or no benefit from the potash, except a little more straw. The next plot was good and I did not wait for the question, but simply said, “ammonia,” and the next “ammonia,” and the next “ammonia.”—Standing still and looking at the wheat, my father asked, “Joe, where can I get this ammonia?” He had previously been a little skeptical as to the value of chemistry, and had not a high opinion of “book farmers,” but that wheat-crop compelled him to admit “that perhaps, after all, there might be some good in it.” At any rate, he wanted to know where he could get ammonia. And, now, as then, every good farmer asks the same question: “Where can I get ammonia?” Before we attempt to answer the question, let us look at the next year’s experiments.—The following is the results of the experiments the seventh year, 1849-50.

Experiments at Rothamsted on the Growth of Wheat, Year after Year, on the same Land.

TABLE VII.—MANURES AND PRODUCE; 7TH SEASON, 1849-50. AFTER THE HARVEST OF 1849 THE FIELD WAS TILE-DRAINED IN EVERY ALTERNATE FURROW, 2 TO 3 FEET DEEP. MANURES AND SEED (RED CLUSTER), SOWN IN AUTUMN, 1849.

Manures Produce

FM Farm-yard Manure. P-A Pearl-ash. S-A Soda-ash. SMg Sulphate of Magnesia. SPL Superphosphate of Lime. B-A Bone-ash. SAc Sulphuric Acid. (Sp. gr. 1.7) MAc Muriatic Acid. SAm Sulphate of Ammonia. MAm Muriate of Ammonia. RC Rape-cake. Wt/Bu. Weight per Bushel. OC Offal Corn. TC Total Corn. S&C Straw and Chaff. TP/C&S Total Produce (Corn and Straw.) C Corn. TP Total Produce. OCD Offal Corn to 100 Dressed. C100 Corn to 100 Straw.

P l o t s. Manures per Acre. Produce per Acre, etc. Increase per Acre by Manure.

SPL Dressed corn.

FM P-A S-A SMg B-A SAc MAc SAm MAm RC Quantity Wt/Bu. OC TC S&C TP C&S C S&C TP OC 100 C100

Tons. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. Bush. Pks. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs.

0 .. .. .. .. 600 450 .. .. .. .. 19 1½ 60.8 42 1220 2037 3257 218 318 536 3.5 59.9

1 .. 600 400 200 .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ..

2 14 .. .. .. .. .. .. .. .. .. 28 2 61.9 98 1861 3245 5106 859 1526 2385 5.4 57.3

3 Unmanured. .. .. .. .. .. .. .. .. 15 3¼ 60.6 44 1002 1719 2721 .. .. .. 4.5 58.2

4 .. .. .. .. 200 .. 200 300 .. .. 27 3 61.2 87 1785 3312 5097 783 1593 2376 5.1 53.9

5a .. 300 200 100 200 150 .. 250 250 .. 29 3½ 60.4 171 1974 4504 6478 972 2785 3757 9.5 43.8

5b .. 300 200 100 200 150 .. 250 250 .. 30 3 60.4 160 2018 4379 6397 1016 2660 3676 8.6 46.1

6a .. 300 200 100 200 150 .. 200 200 .. 30 0½ 61.1 119 1960 3927 5887 958 2208 3166 6.3 49.9

6b .. *00 200 100 200 150 .. 200 200 .. 29 3½ 61.3 148 1980 3959 5939 978 2240 3218 8.0 50.0

7a .. 300 200 100 200 150 .. 200 200 500 32 1 61.0 167 2134 4485 6619 1132 2766 3898 8.4 47.9

7b .. 300 200 100 200 150 .. 200 200 500 32 0¼ 61.2 150 2112 4280 6392 1110 2561 3671 7.6 49.4

8a .. .. .. .. .. .. .. 200 200 .. 28 3 61.1 101 1856 3407 5263 854 1688 2542 5.5 54.5

8b .. .. .. .. .. .. .. 200 200 .. 30 1 61.0 103 1948 3591 5539 946 1872 2818 5.6 54.2

9a .. .. .. .. .. .. .. 200 200 .. 30 1½ 60.4 118 1951 3550 5501 949 1831 2780 6.3 55.0

9b .. .. .. .. .. .. .. 200 200 .. 27 2¾ 60.8 80 1762 3165 4927 760 1446 2206 4.7 55.7

10a .. .. .. .. .. .. .. 200 200 .. 26 3¾ 60.2 100 1721 3089 4810 719 1370 2089 6.1 55.7

10b .. 300 200 100 200 150 .. .. .. .. 17 3¾ 61.1 76 1171 1949 3120 169 230 399 6.8 60.1

11a .. .. .. .. 200 150 .. 200 200 .. 30 3¼ 61.0 121 2001 3806 5807 999 2087 3086 6.4 52.6

11b .. .. .. .. 200 150 .. 200 200 .. 29 1½ 61.1 145 1940 3741 5681 938 2022 2960 8.0 51.9

12a .. 300 .. .. 200 150 .. 200 200 .. 29 3¾ 61.5 94 1935 3921 5856 933 2202 3135 5.1 49.4

12b .. 300 .. .. 200 150 .. 200 200 .. 30 3¾ 61.4 115 2013 3905 5918 1011 2186 3197 5.9 51.5

13a .. 300 .. .. 200 150 .. 200 200 .. 31 3¾ 60.2 105 2027 4026 6053 1025 2307 3332 5.4 50.3

13b .. 300 .. .. 200 150 .. 200 200 .. 30 1½ 61.0 111 1964 4008 5972 962 2289 3251 6.0 49.0

14a .. 300 .. .. 200 150 .. 200 200 .. 31 1¾ 61.1 102 2023 4052 6075 1021 2333 3354 5.3 49.9

14b .. 300 .. .. 200 150 .. 200 200 .. 31 1½ 61.5 65 1995 4015 6010 993 2296 3289 3.2 49.7

15a .. 300 200 100 200 .. 200 300 .. .. 26 0¼ 61.5 90 1693 3321 5014 691 1602 2293 5.7 51.0

15b .. 300 200 100 200 .. 200 300 .. 500 30 3½ 61.0 59 1942 3926 5868 940 2207 3147 3.0 49.5

16a .. 300 200 100 200 150 .. 200 200 .. 33 2½ 60.3 108 2134 5103 7237 1132 3384 4516 5.3 41.8

16b .. 300 200 100 200 150 .. 200 200 .. 33 3 60.4 122 2159 4615 6774 1157 2896 4053 6.0 46.8

17a .. 300 200 100 200 150 .. 200 200 .. 31 1 61.2 73 1985 4126 6111 983 2407 3390 3.8 48.1

17b .. 300 200 100 200 150 .. 200 200 .. 29 2½ 61.5 139 1961 4034 5995 959 2315 3274 7.7 48.6

18a .. 300 200 100 200 150 .. 200 200 .. 29 3¼ 61.2 110 1934 3927 5861 932 2208 3140 6.1 49.3

18b .. 300 200 100 200 150 .. 200 200 .. 28 2½ 60.9 103 1845 3844 5689 843 2125 2968 5.7 48.0

19 .. .. .. .. 200 .. 200 300 .. 500 29 0 60.8 88 1850 3527 5377 848 1808 2656 4.9 52.4

20 Unmanured. .. .. .. .. .. .. .. .. 14 0 59.1 40 868 1639 2507 -134 -80 -214 4.5 53.0

21} Mixture of the residue of most of the other manures. .. .. .. .. .. .. .. .. .. .. .. .. ..

22}

The summer of 1850 was unusually cool and unfavorable for wheat. It will be seen that on all the plots the yield of grain is considerably lower than last year, with a greater growth of straw.

You will notice that 10b, which last year gave, with ammonia-salts alone, 32¼ bushels, this year, with superphosphate, potash, soda, and sulphate of magnesia, gives less than 18 bushels, while the adjoining plot, dressed with ammonia, gives nearly 27 bushels. In other words, the ammonia alone gives 9 bushels per acre more than this large dressing of superphosphate, potash, etc.

On the three plots, 8a, 8b and 9a, a dressing of ammonia-salts alone gives in each case, a larger yield, both of grain and straw, than the 14 tons of barn-yard manure on plot 2. And recollect that this plot has now received 98 tons of manure in seven years.

“That,” said the Doctor, “is certainly a very remarkable fact.”

“It is so,” said the Deacon.

“But what of it?” asked the Squire, “even the Professor, here, does not advise the use of ammonia-salts for wheat.”

“That is so,” said I, “but perhaps I am mistaken. Such facts as those just given, though I have been acquainted with them for many years, sometimes incline me to doubt the soundness of my conclusions. Still, on the whole, I think I am right.”

“We all know,” said the Deacon, “that you have great respect for your own opinions.”

“Never mind all that,” said the Doctor, “but tell us just what you think on this subject.”

“In brief,” said I, “my opinion is this. We need ammonia for wheat. But though ammonia-salts and nitrate of soda can often be used with decided profit, yet I feel sure that we can get ammonia or nitrogen at a less cost per lb. by buying bran, malt-roots, cotton-seed cake, and other foods, and using them for the double purpose of feeding stock and making manure.”

“I admit that such is the case,” said the Doctor, “but here is a plot of land that has now had 14 tons of manure every year for seven years, and yet there is a plot along side, dressed with ammonia-salts furnishing less than half the ammonia contained in the 14 tons of manure, that produces a better yield of wheat.”

“That,” said I, “is simply because the nitrogen in the manure is not in an available condition. And the practical question is, how to make the nitrogen in our manure more immediately available. It is one of the most important questions which agricultural science is called upon to answer. Until we get more light, I feel sure in saying that one of the best methods is, to feed our animals on richer and more easily digested food.”

The following table gives the results of the eighth season of 1850-51.

Experiments at Rothamsted on the Growth of Wheat, Year after Year, on the same Land.

TABLE VIII.—MANURES AND PRODUCE; 8TH SEASON. 1850-51. MANURES AND SEED (RED CLUSTER), SOWN AUTUMN, 1850.

Manures Produce

FM Farm-yard Manure. WSC Cut Wheat-straw and Chaff. CS Common Salt. SP Sulphate of Potass. S-A Soda-ash. SMg Sulphate of Magnesia. SPL Superphosphate of Lime. B-A Bone-ash. SAc Sulphuric Acid. (Sp. gr. 1.7) MAc Muriatic Acid. SAm Sulphate of Ammonia. MAm Muriate of Ammonia. RC Rape-cake. Wt/Bu. Weight per Bushel. OC Offal Corn. TC Total Corn. S&C Straw and Chaff. TP/C&S Total Produce (Corn and Straw). C Corn. S&C Straw and Chaff. TP Total Produce. OCD Offal Corn to 100 Dressed. C100 Corn to 100 Straw.

P l o t s. Manures per Acre. Produce per Acre, etc. Increase per Acre by Manure.

SPL Dressed corn.

FM WSC CS SP S-A SMg B-A SAc MAc SAm MAm RC Quantity Wt/Bu. OC TC S&C TP C&S C S&C TP OC 100 C100

Tons. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. Bush. Pks. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs.

0 .. .. .. .. .. .. 600 450 .. .. .. .. 18 3½ 61.9 125 1296 1862 3158 213 235 448 10.7 69.6

1 .. .. .. 600 400 200 .. .. .. .. .. .. 18 1¼ 61.7 124 1251 1845 3096 168 218 386 11.0 67.8

2 14 .. .. .. .. .. .. .. .. .. .. .. 29 2½ 63.6 166 2049 3094 5143 966 1467 2433 8.8 66.2

3 Unmanured. .. .. .. .. .. .. .. .. .. .. 15 3½ 61.1 114 1083 1627 2710 .. .. .. 11.8 66.6

4 .. .. .. .. .. .. 200 .. 200 400 .. .. 28 0½ 62.6 159 1919 2949 4868 836 1322 2158 9.0 65.1

5a .. .. .. 300 200 100 200 150 .. 300 300 .. 36 0 63.3 194 2473 4131 6604 1390 2504 3894 8.6 59.9

5b .. .. .. 300 200 100 200 150 .. 300 300 .. 37 3¾ 63.3 213 2611 4294 6905 1528 2667 4195 8.9 60.8

6a .. .. .. 300 200 100 200 150 .. 200 200 .. 33 1¾ 63.3 154 2271 3624 5895 1188 1997 3185 7.2 62.6

6b .. .. .. 300 200 100 200 150 .. 200 200 .. 31 0¼ 62.3 189 2119 3507 5626 1036 1880 2916 9.8 60.4

7a .. .. .. 300 200 100 200 150 .. 200 200 1000 36 3½ 63.0 201 2524 4587 7111 1441 2960 4401 8.7 55.0

7b .. .. .. 300 200 100 200 150 .. 200 200 1000 37 1½ 63.0 178 2532 4302 6834 1449 2675 4124 7.6 58.8

8a .. 5000 .. .. .. .. .. .. .. .. .. .. 26 0¾ 62.8 141 1785 2769 4554 702 1142 1844 8.6 64.5

8b .. .. .. 300 200 100 200 150 .. 100 100 .. 27 2¼ 62.6 137 1863 2830 4693 780 1203 1983 7.9 65.8

9a .. .. .. .. .. .. .. .. .. 200 200 .. 31 1½ 62.4 182 2142 3252 5394 1059 1625 2684 9.3 65.9

9b .. .. .. .. .. .. .. .. .. 200 200 .. 29 0¾ 62.0 170 1970 2942 4912 887 1315 2202 9.5 67.0

10a .. .. .. .. .. .. .. .. .. 200 200 .. 28 3½ 61.9 179 1966 3070 5036 883 1443 2326 10.0 64.0

10b .. .. .. .. .. .. .. .. .. 200 200 .. 28 2½ 62.5 149 1937 3048 4985 854 1421 2275 8.3 63.5

11a .. .. .. .. .. .. 200 150 .. 200 200 .. 32 2¾ 62.3 181 2216 3386 5602 1133 1759 2892 8.9 65.4

11b .. .. .. .. .. .. 200 150 .. 200 200 .. 31 2¾ 62.5 181 2163 3302 5465 1080 1675 2755 9.1 65.5

12a .. .. .. 200 100 .. 200 150 .. 200 200 .. 32 3 63.1 165 2234 3600 5834 1151 1973 3124 8.0 62.0

12b .. .. .. 200 100 .. 200 150 .. 200 200 .. 32 2¼ 62.5 166 2203 3581 5784 1120 1954 3074 8.2 61.5

13a .. .. .. 300 .. .. 200 150 .. 200 200 .. 30 2¾ 62.6 180 2102 3544 5646 1019 1917 2936 9.4 59.3

13b .. .. .. 300 .. .. 200 150 .. 200 200 .. 30 3¼ 62.3 160 2083 3440 5523 1000 1813 2813 8.3 60.5

14a .. .. .. 200 .. 100 200 150 .. 200 200 .. 31 0¼ 62.9 168 2120 3605 5725 1037 1978 3015 8.6 58.8

14b .. .. .. 200 .. 100 200 150 .. 200 200 .. 31 0½ 62.8 165 2121 3537 5658 1038 1910 2948 8.4 59.9

15a .. .. .. 200 100 100 200 .. 200 400 .. .. 27 0½ 62.7 138 1839 3041 4880 756 1414 2170 8.1 60.5

15b .. .. .. 200 100 100 200 .. 200 400 .. 500 30 2½ 62.9 148 2077 3432 5509 994 1805 2799 7.6 60.5

16a .. .. 336¹ 200 100 100 200 150 .. 300 300 .. 36 3¼ 63.5 161 2499 4234 6733 1416 2607 4023 6.9 59.0

16b .. .. .. 200 100 100 200 150 .. 300 300 .. 36 2¾ 63.4 176 2501 4332 6833 1418 2705 4123 7.6 57.7

17a .. .. .. 200 100 100 200 150 .. 200 200 .. 31 3½ 63.3 131 2149 3597 5746 1066 1970 3036 6.5 59.7

17b .. .. .. 200 100 100 200 150 .. 200 200 .. 30 2¼ 63.1 152 2079 3406 5485 996 1779 2775 7.9 61.0

18a .. .. .. .. .. .. .. .. .. 200 200 .. 30 3¼ 63.0 139 2083 3390 5473 1000 1763 2763 7.2 64.1

18b .. .. .. .. .. .. .. .. .. 200 200 .. 31 0¾ 62.4 143 2090 3586 5676 1007 1959 2966 7.3 58.3

19 .. .. .. .. .. .. 200 .. 200 300 .. 500 30 1 62.4 144 2031 3348 5379 948 1721 2669 7.7 60.7

20} Unmanured {.. .. .. .. .. .. .. .. .. .. 14 1 60.8 89 956 1609 2565 -127 -18 -145 10.2 59.4

21}{.. .. .. .. .. .. .. .. .. .. 17 3¼ 61.9 127 1232 1763 2995 149 136 285 11.5 69.9

22} {.. .. .. .. .. .. .. .. .. ..

The plot continuously unmanured, gives about 16 bushels of wheat per acre.

The plot with barn-yard manure, nearly 30 bushels per acre.

400 lbs. of ammonia-salts alone, on plot 9a, 31¼ bushels; on 9b, 29 bushels; on 10a and 10b, nearly 29 bushels each. This is remarkable uniformity.

400 lbs. ammonia-salts and a large quantity of mineral manures in addition, on twelve different plots, average not quite 32 bushels per acre.

“The superphosphate and minerals,” said the Deacon, “do not seem to do much good, that is a fact.”

You will notice that 336 lbs. of common salt was sown on plot 16a. It does not seem to have done the slightest good. Where the salt was used, there is 2 lbs. less grain and 98 lbs. less straw than on the adjoining plot 16b, where no salt was used, but otherwise manured alike. It would seem, however, that the quality of the grain was slightly improved by the salt. The salt was sown in March as a top-dressing.

“It would have been better,” said the Deacon. “to have sown it in autumn with the other manures.”

“The Deacon is right,” said I, “but it so happens that the next year and the year after, the salt was applied at the same time as the other manures. It gave an increase of 94 lbs. of grain and 61 lbs. of straw in 1851, but the following year the same quantity of salt used on the same plot did more harm than good.”

Before we leave the results of this year, it should be observed that on 8a, 5,000 lbs. of cut straw and chaff were used per acre. I do not recollect seeing anything in regard to it. And yet the result was very remarkable—so much so indeed, that it is a matter of regret that the experiment was not repeated.

This 5,000 lbs. of straw and chaff gave an increase of more than 10 bushels per acre over the continuously unmanured plot.

“Good,” said the Deacon, “I have always told you that you under-estimated the value of straw, especially in regard to its mechanical action.”

I did not reply to this remark of the good Deacon. I have never doubted the good effects of anything that lightens up a clay soil and renders it warmer and more porous. I suppose the great benefit derived from this application of straw must be attributed to its ameliorating action on the soil. The 5,000 lbs. of straw and chaff produced a crop within nearly 3 bushels per acre of the plot manured every year with 14 tons of barn-yard manure.

“I am surprised,” said the Doctor, “that salt did no good. I have seen many instances in which it has had a wonderful effect on wheat.”

“Yes,” said I, “and our experienced friend, John Johnston, is very decidedly of the opinion that its use is highly profitable. He sows a barrel of salt per acre broadcast on the land at the time he sows his wheat, and I have myself seen it produce a decided improvement in the crop.”

We have now given the results of the first eight years of the experiments. From this time forward, the same manures were used year after year on the same plot.

The results are given in the accompanying tables for the following twelve years—harvests for 1852-53-54-55-56-57-58-59-60-61-62 and 1863. Such another set of experiments are not to be found in the world, and they deserve and will receive the careful study of every intelligent American farmer.

“I am with you there,” said the Deacon. “You seem to think that I do not appreciate the labors of scientific men. I do. Such experiments as these we are examining command the respect of every intelligent farmer. I may not fully understand them, but I can see clearly enough that they are of great value.”

Experiments at Rothamsted on the Growth of Wheat, Year after Year, on the same Land.

Table IX.—Manures per Acre per Annum (with the exceptions explained in the Notes on p. 203), for 12 Years in succession—namely, for the 9th, 10th, 11th, 12th, 13th, 14th, 15th, 16th, 17th, 18th, 19th, and 20th Seasons: that is, for the crops of Harvests 1852-53-54-55-56-57-58-59-60-61-62 and 1863.*

FM Farm-yard Manure. CS Common Salt. SP Sulphate of Potass.¹ SS Sulphate of Soda.¹ SMg Sulphate of Magnesia.¹ SPL Superphosphate of Lime. B-A Bone-ash. SAc Sulphuric Acid. (Sp. gr. 1.7) MAc Muriatic Acid. SAm Sulphate of Ammonia. MAm Muriate of Ammonia. NS Nitrate of Soda. RC Rape-cake.

P l o t s. Manures per Acre per Annum for 12 Years, 1851-2 to 1862-3 inclusive, except in the cases explained in the Notes on p. 203.

Superphosphate of Lime.

FM CS SP SS SMg B-A SAc MAc SAm MAm NS RC

Tons. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs.

0 .. .. .. .. .. 600 450 .. .. .. .. ..

1 .. .. 600 400 200 .. .. .. .. .. .. ..

2 14 .. .. .. .. .. .. .. .. .. .. ..

3 Unmanured .. .. .. .. .. .. .. .. .. ..

4 Unmanured .. .. .. .. .. .. .. .. .. ..

5a .. .. 300 200 100 200 150 .. .. .. .. ..

5b .. .. 300 200 100 200 150 .. .. .. .. ..

6a .. .. 300 200 100 200 150 .. 100 100 .. ..

6b .. .. 300 200 100 200 150 .. 100 100 .. ..

7a .. .. 300 200 100 200 150 .. 200 200 .. ..

7b .. .. 300 200 100 200 150 .. 200 200 .. ..

8a .. .. 300 200 100 200 150 .. 300 300 .. ..

8b .. .. 300 200 100 200 150 .. 300 300 .. ..

²9a .. .. 300 200 100 200 150 .. .. .. 550 ..

³9b .. .. .. .. .. .. .. .. .. .. 550 ..

10a .. .. .. .. .. .. .. .. 200 200 .. ..

10b .. .. .. .. .. .. .. .. 200 200 .. ..

11a .. .. .. .. .. 200 150 .. 200 200 .. ..

11b .. .. .. .. .. 200 150 .. 200 200 .. ..

12a .. .. .. 550 .. 200 150 .. 200 200 .. ..

12b .. .. .. 550 .. 200 150 .. 200 200 .. ..

13a .. .. 300 .. .. 200 150 .. 200 200 .. ..

13b .. .. 300 .. .. 200 150 .. 200 200 .. ..

14a .. .. .. .. 420 200 150 .. 200 200 .. ..

14b .. .. .. .. 420 200 150 .. 200 200 .. ..

15a .. .. 300 200 100 200 .. 200 400 .. .. ..

15b .. .. 300 200 100 200 .. 200 300 .. .. 500

16a .. 336⁴ 300 200 100 200 150 .. 400 400 .. ..

16b .. .. 300 200 100 200 150 .. 400 400 .. ..

{17a .. .. .. .. .. .. .. .. 200 200 .. ..

⁵{17b .. .. .. .. .. .. .. .. 200 200 .. ..

{18a .. .. 300 200 100 200 150 .. .. .. .. ..

⁵{18b .. .. 300 200 100 200 150 .. .. .. .. ..

19 .. .. .. .. .. 200 .. 200 300 .. .. 500

20 Unmanured .. .. .. .. .. .. .. .. .. ..

21 .. .. 300 200 100 .. .. .. .. 100 .. ..

22 .. .. 300 200 100 .. .. .. 100 .. .. ..

NOTES TO TABLE IX. (p. 202.)

Table X.—Produce of the 9th Season, 1851-2. Seed (Red Cluster) sown November 7, 1851; Crop cut August 24, 1852.

Table XI.—Produce of the 10th Season, 1853. Seed (Red Rostock) sown March 16; Crop cut September 10, and carted September 20, 1853.

Wt/Bu. Weight per Bushel. C&S Corn and Straw.

P l o t s. Produce per Acre, etc. (For the Manures see pp. 202 and 203.) P l o t s. Produce per Acre, etc. (For the Manures see pp. 202 and 203.)

Dressed Corn. Total Corn Total Produce (C&S) Dressed Corn. Total Corn Total Produce (C&S)

Quantity Wt/Bu. Quantity Wt/Bu.

Bu. Pks. lbs. lbs. lbs. Bu. Pks. lbs. lbs. lbs.

0 15 0¾ 55.8 919 2625 0 9 0¾ 49.1 599 2406

1 13 1 56.9 825 2322 1 6 1¾ 46.1 404 2036

2 27 2¼ 58.2 1716 5173 2 19 0½ 51.1 1120 4492

3 13 3¼ 56.6 860 2457 3 5 3¼ 45.1 359 1772

4 13 1¼ 57.3 870 2441 4 7 1 46.1 446 2116

5a 16 3 57.5 1038 2941 5a 10 0 48.9 587 2538

5b 17 0¼ 57.3 1065 3097 5b 10 1 48.9 611 2741

6a 20 3 57.6 1288 3869 6a 16 3¼ 51.8 978 3755

6b 20 3½ 57.5 1300 3904 6b 19 1 51.8 1072 3870

7a 26 2½ 56.0 1615 5465 7a 23 2½ 52.2 1369 5110

7b 26 3¾ 55.8 1613 5415 7b 23 2¼ 51.1 1357 5091

8a 27 3½ 55.9 1699 5505 8a 22 1¼ 51.1 1346 5312

8b 27 0½ 55.9 1651 5423 8b 24 2¼ 51.1 1425 5352

9a 25 2 55.6 1591 5305 9a 11 1 47.7 691 3090

9b 24 1¾ 55.3 1509 4883 9b 10 1¾ 46.1 649 2902

10a 21 3½ 55.9 1320 4107 10a 9 3¾ 48.9 642 2691

10b 22 0¼ 57.3 1343 4162 10b 15 2 49.8 896 3578

11a 24 0¾ 55.6 1472 4553 11a 17 2 50.1 1015 3539

11b 22 1½ 55.9 1387 4299 11b 18 2¾ 51.1 1073 3780

12a 24 1¾ 57.4 1503 4760 12a 22 0 52.0 1283 4948

12b 24 1¼ 57.3 1492 4721 12b 23 3¼ 51.1 1375 5079

13a 24 0 57.5 1480 4702 13a 22 1¼ 52.1 1341 5045

13b 23 3¾ 57.1 1476 4765 13b 23 2½ 51.1 1396 5308

14a 24 1¾ 56.9 1507 5054 14a 21 2 51.2 1322 4793

14b 25 0¼ 56.7 1530 5137 14b 23 0¾ 52.6 1347 5108

15a 23 1¼ 57.4 1451 4663 15a 19 0 51.1 1143 4504

15b 25 0½ 56.8 1520 4941 15b 23 2½ 51.1 1351 5107

16a 28 3½ 55.0 1794 6471 16a 24 1½ 52.5 1496 6400

16b 28 0 54.5 1700 6316 16b 25 3¼ 52.5 1537 6556

17a 25 2 56.5 1577 5311 17a 8 1¾ 49.8 520 2516

17b 24 1½ 56.9 1520 4986 17b 8 3¾ 48.9 539 2551

18a 13 3 57.0 869 2556 18a 17 3¼ 52.9 1111 4496

18b 14 3¾ 56.7 921 2685 18b 20 3 52.1 1256 5052

19 24 3¾ 56.1 1582 4979 19 19 1¼ 52.6 1160 4373

20 14 0¾ 56.6 875 2452 20 5 3¼ 47.8 425 2084

21 19 1¾ 56.9 1177 3285 21 12 3¾ 50.4 753 2934

22 19 2¼ 55.9 1176 3355 22 10 1 49.4 592 2452

Table XII.—Produce of the 11th Season, 1853-4. Seed (Red Rostock) sown November 12, 1853; Crop cut August 21, and carted August 31, 1854.

Table XIII.—Produce of the 12th Season, 1854-5. Seed (Red Rostock) sown November 9, 1854; Crop cut August 26, and carted September 2, 1855.

Wt/Bu. Weight per Bushel. C&S Corn and Straw.

P l o t s. Produce per Acre, etc. (For the Manures see pp. 202 and 203.) P l o t s. Produce per Acre, etc. (For the Manures see pp. 202 and 203.)

Dressed Corn. Total Corn Total Produce (C&S) Dressed Corn. Total Corn Total Produce (C&S)

Quantity Wt/Bu. Quantity Wt/Bu.

Bu. Pks. lbs. lbs. lbs. Bu. Pks. lbs. lbs. lbs.

0 26 1¾ 61.0 1672 3786 0 17 0 60.7 1096 2822

1 24 1½ 60.2 1529 4060 1 18 2 60.5 1179 3069

2 41 0½ 62.5 2675 7125 2 34 2½ 62.0 2237 6082

3 21 0¼ 60.6 1359 3496 3 17 0 59.2 1072 2859

4 23 3½ 61.1 1521 3859 4 18 2½ 59.5 1168 3000

5a 24 1½ 61.0 1578 4098 5a 18 2 59.9 1157 2976

5b 24 0 61.6 1532 4035 5b 18 0½ 60.1 1143 2943

6a 33 2¾ 61.8 2186 6031 6a 27 3 60.3 1753 4590

6b 34 2¼ 61.8 2239 6294 6b 28 1 60.9 1811 4848

7a 45 2¼ 61.9 2950 8553 7a 32 2¾ 59.4 2084 5995

7b 45 1½ 61.8 2944 8440 7b 33 1¼ 59.5 2138 6296

8a 47 1¾ 61.4 3065 9200 8a 29 3 58.8 1909 5747

8b 49 2½ 61.8 3208 9325 8b 33 0¾ 58.7 2153 6495

9a 38 3 60.7 2456 6598 9a 29 2½ 58.3 1932 5878

9b 38 3½ 60.7 2480 6723 9b 25 1½ 57.3 1605 4817

10a 34 1½ 60.5 2211 5808 10a 19 3¾ 57.1 1285 3797

10b 39 0¾ 61.6 2535 7003 10b 28 0½ 58.9 1805 5073

11a 44 2 61.1 2859 8006 11a 18 3 55.3 1210 3694

11b 43 0½ 61.2 2756 7776 11b 24 2½ 56.3 1580 4733

12a 45 3¼ 62.2 2966 8469 12a 30 0¼ 59.5 1940 5478

12b 45 1½ 62.2 2939 8412 12b 33 2 60.2 2172 6182

13a 45 0½ 62.2 2913 8311 13a 29 0 59.9 1924 5427

13b 43 3½ 62.2 2858 8403 13b 32 2 60.4 2110 5980