Talks on Manures Part 8

This experiment of Dr. Vlcker proves conclusively that manure can be kept in a rapid state of fermentation for six months during winter, with little loss of nitrogen or other fertilizing matter.

During fermentation a portion of the insoluble matter of the dung becomes soluble, and if the manure is then kept in a heap exposed to rain, there is a great loss of fertilizing matter. This is precisely what we should expect. We ferment manure to make it more readily available as plant-food, and when we have attained our object, the manure should be applied to the land. We keep winter apples in the cellar until they get ripe. As soon as they are ripe, they should be eaten, or they will rapidly decay. This is well understood. And it should be equally well known that manure, after it has been fermenting in a heap for six months, cannot safely be kept for another six months exposed to the weather.

The following table shows the composition of 100 lbs. of the farm-yard manure, at different periods of the year:

Composition of 100 Lbs. of Fresh Farm-Yard Manure (No. I.) Exposed in Natural State, at Different Periods of the Year.

-------------------------+--------+--------+--------+--------+-------- When put Feb. 14, Apr. 30, Aug. 23, Nov. 15, up, Nov. 1855. 1855. 1855. 1855.

3, 1854. -------------------------+--------+--------+--------+--------+-------- Water 66.17 69.83 65.95 75.49 74.29 Soluble organic matter 2.48 3.86 4.27 2.95 2.74 Soluble inorganic matter 1.54 2.97 2.86 1.97 1.87 Insoluble organic matter 25.76 18.44 19.23 12.20 10.89 Insoluble mineral matter 4.05 4.90 7.69 7.39 10.21 +--------+--------+--------+--------+-------- 100.00 100.00 100.00 100.00 100.00 Containing nitrogen .149 .27 .30 .19 .18 Equal to ammonia .181 .32 .36 .23 .21 Containing nitrogen .494 .47 .59 .47 .47 Equal to ammonia .599 .57 .71 .62 .57 Total amount of nitrogen .643 .74 .89 .66 .65 Equal to ammonia .780 .89 1.07 .85 .78 Ammonia in a free state .034 .049 .008 .010 .006 Ammonia in form of salts easily decomposed by quicklime .088 .064 .085 .038 .041 Total amt. of organic 28.24 22.30 23.50 15.15 13.63 matter Total amt. of mineral 5.59 7.87 10.55 9.36 12.08 substances -------------------------+--------+--------+--------+--------+--------

It will be seen that two-thirds of the fresh manure is water. After fermenting in an exposed heap for six months, it still contains about the same _percentage_ of water. When kept in the heap until August, the percentage of water is much greater. Of four tons of such manure, three tons are water.

Of _Nitrogen_, the most valuable ingredient of the manure, the fresh dung, contained 0.64 per cent; after fermenting six months, it contained 0.89 per cent. Six months later, it contained 0.65 per cent, or about the same amount as the fresh manure.

Of mineral matter, or ash, this fresh farm-yard manure contained 5.59 per cent; of which 1.54 was soluble in water, and 4.05 insoluble. After fermenting in the heap for six months, the manure contained 10.55 per cent of ash, of which 2.86 was soluble, and 7.69 insoluble. Six months later, the soluble ash had decreased to 1.97 per cent.

The following table shows the composition of the manure, at different periods, in the _dry state_. In other words, supposing all the water to be removed from the manure, its composition would be as follows:

Composition of Fresh Farm-Yard Manure (No. I.) Exposed.

Calculated Dry.

-------------------------+--------+--------+--------+--------+-------- When put Feb. 14, Apr. 30, Aug. 23, Nov. 15, up, Nov. 1855. 1855. 1855. 1855.

3, 1854. -------------------------+--------+--------+--------+--------+-------- Soluble organic matter 7.33 12.79 12.54 12.04 10.65 Soluble inorganic matter 4.55 9.84 8.39 8.03 7.27 Insoluble organic matter 76.15 61.12 56.49 49.77 42.35 Insoluble mineral matter 11.97 16.25 22.58 30.16 39.73 +--------+--------+--------+--------+-------- 100.00 100.00 100.00 100.00 100.00 Containing nitrogen .44 .91 .88 .77 .72 Equal to ammonia .53 1.10 1.06 .93 .88 Containing nitrogen 1.46 1.55 1.75 1.92 1.85 Equal to ammonia 1.77 1.88 2.12 2.33 2.24 Total amount of nitrogen 1.90 2.46 2.63 2.69 2.57 Equal to ammonia 2.30 2.98 3.18 3.26 3.12 Ammonia in free state .10 .062 .023 .041 .023 Ammonia in form of salts easily decomposed by quicklime .26 .212 .249 .154 .159 Total amount of organic matter 83.48 73.91 69.03 61.81 53.00 Total amount of mineral substances 16.52 26.09 30.97 38.19 47.00 -------------------------+--------+--------+--------+--------+--------

"A comparison of these different a.n.a.lyses," says Dr. Vlcker, "points out clearly the changes which fresh farm-yard manure undergoes on keeping in a heap, exposed to the influence of the weather during a period of twelve months and twelve days.

"1. It will be perceived that the proportion of organic matter steadily diminishes from month to month, until the original percentage of organic matter in the dry manure, amounting to 83.48 per cent, becomes reduced to 53 per cent.

"2. On the other hand, the total percentage of mineral matter rises as steadily as that of the organic matter falls.

"3. It will be seen that the loss in organic matter affects the percentage of insoluble organic matters more than the percentage of soluble organic substances.

"4. The percentage of soluble organic matters, indeed, increased considerably during the first experimental period; it rose, namely, from 7.33 per cent to 12.79 per cent. Examined again on the 30th of April, very nearly the same percentage of soluble organic matter, as on February the 14th, was found. The August a.n.a.lysis shows but a slight decrease in the percentage of soluble organic matters, while there is a decrease of 2 per cent of soluble organic matters when the November a.n.a.lysis is compared with the February a.n.a.lysis.

"5. The soluble mineral matters in this manure rise or fall in the different experimental periods in the same order as the soluble organic matters. Thus, in February, 9.84 per cent of soluble mineral matters were found, whilst the manure contained only 4.55 per cent, when put up into a heap in November, 1854. Gradually, however, the proportion of soluble mineral matters again diminished, and became reduced to 7.27 per cent, on the examination of the manure in November, 1855.

"6. A similar regularity will be observed in the percentage of nitrogen contained in the soluble organic matters.

"7. In the insoluble organic matters, the percentage of nitrogen regularly increased from November, 1854, up to the 23d of August, notwithstanding the rapid diminution of the percentage of insoluble organic matter. For the last experimental period, the percentage of nitrogen in the insoluble matter is nearly the same as on August 23d.

"8. With respect to the total percentage of nitrogen in the fresh manure, examined at different periods of the year, it will be seen that the February manure contains about one-half per cent more of nitrogen than the manure in a perfectly fresh state. On the 30th of April, the percentage of nitrogen again slightly increased; on August 23d, it remained stationary, and had sunk but very little when last examined on the 15th of November, 1855.

"This series of a.n.a.lyses thus shows that fresh farm-yard manure rapidly becomes more soluble in water, but that this desirable change is realized at the expense of a large proportion of organic matters. It likewise proves, in an unmistakable manner, that there is no advantage in keeping farm-yard manure for too long a period; for, after February, neither the percentage of soluble organic, nor that of soluble mineral matter, has become greater, and the percentage of nitrogen in the manure of April and August is only a very little higher than in February."

"Before you go any further," said the Deacon, "answer me this question: Suppose I take five tons of farm-yard manure, and put it in a heap on the 3d of November, tell me, 1st, what that heap will contain when first made; 2d, what the heap will contain April 30th; and, 3d, what the heap will contain August 23d."

Here is the table:

Contents of a Heap of Manure at Different Periods, Exposed to Rain, etc.

-------------------------------+---------+---------+---------+-------- When Apr. 30. Aug. 23. Nov. 15.

put up, Nov. 3. -------------------------------+---------+---------+---------+-------- Total weight of manure in heap 10,000 7,138 7,025 6,954 Water in the heap of manure 6,617 4,707 5,304 5,167 Total organic matter 2,824 1,678 1,034 947 Total inorganic matter 559 753 657 840 Total nitrogen in heap 64.3 63.9 46.3 46.0 Total soluble organic matter 248 305 207 190 Total insoluble organic matter 2,576 1,373 857 757 Soluble mineral matter 154 204 138 130 Insoluble mineral matter 405 549 519 710 Nitrogen in soluble matter 14.9 21.4 13.2 12.9 Nitrogen in insoluble matter 49.4 42.5 33.1 33.1 -------------------------------+---------+---------+---------+--------

The Deacon put on his spectacles and studied the above table carefully for some time. "That tells the whole story," said he, "you put five tons of fresh manure in a heap, it ferments and gets warm, and nearly one ton of water is driven off by the heat."

"Yes," said the Doctor, "you see that over half a ton (1,146 lbs.) of dry organic matter has been slowly burnt up in the heap; giving out as much heat as half a ton of coal burnt in a stove. But this is not all.

The manure is cooked, and steamed, and softened by the process. The organic matter burnt up is of no value. There is little or no loss of nitrogen. The heap contained 64.3 lbs. of nitrogen when put up, and 63.9 lbs. after fermenting six months. And it is evident that the manure is in a much more active and available condition than if it had been applied to the land in the fresh state. There was 14.9 lbs. of nitrogen in a soluble condition in the fresh manure, and 21.4 lbs. in the fermented manure. And what is equally important, you will notice that there is 154 lbs. of soluble ash in the heap of fresh manure, and 204 lbs. in the heap of fermented manure. In other words, 50 lbs. of the insoluble mineral matter had, by the fermentation of the manure, been rendered soluble, and consequently immediately available as plant-food.

This is a very important fact."

The Doctor is right. There is clearly a great advantage in fermenting manure, provided it is done in such a manner as to prevent loss. We have not only less manure to draw out and spread, but the plant-food which it contains, is more soluble and active.

The table we have given shows that there is little or no loss of valuable const.i.tuents, even when manure is fermented in the open air and exposed to ordinary rain and snows during an English winter. But it also shows that when the manure has been fermented for six months, and is then turned and left exposed to the rain of spring and summer, the loss is very considerable.

The five tons (10,000 lbs.,) of fresh manure placed in a heap on the 3d of November, are reduced to 7,138 lbs. by the 30th of April. Of this 4,707 lbs. is water. By the 23d of August, the heap is reduced to 7,025 lbs., of which 5,304 lbs. is water. There is nearly 600 lbs. more water in the heap in August than in April.

Of total nitrogen in the heap, there is 64.3 lbs. in the fresh manure, 63.9 lbs. in April, and only 46.3 lbs. in August. This is a great loss, and there is no compensating gain.

We have seen that, when five tons of manure is fermented for six months, in winter, the nitrogen in the soluble organic matter is increased from 14.9 lbs. to 21.4 lbs. This is a decided advantage. But when the manure is kept for another six months, this soluble nitrogen is decreased from 21.4 lbs. to 13.2 lbs. We lose over 8 lbs. of the most active and available nitrogen.

And the same remarks will apply to the valuable soluble mineral matter.

In the five tons of fresh manure there is 154 lbs. of soluble mineral matter. By fermenting the heap six months, we get 204 lbs., but by keeping the manure six months longer, the soluble mineral matter is reduced to 138 lbs. We lose 66 lbs. of valuable soluble mineral matter.

By fermenting manure for six months in winter, we greatly improve its condition; by keeping it six months longer, we lose largely of the very best and most active parts of the manure.

CHAPTER XV.

KEEPING MANURE UNDER COVER.

Dr. Vlcker, at the same time he made the experiments alluded to in the preceding chapter, placed another heap of manure _under cover_, in a shed. It was the same kind of manure, and was treated precisely as the other--the only difference being that one heap was exposed to the rain, and the other not. The following table gives the results of the weighings of the heap at different times, and also the percentage of loss:

Manure Fermented Under Cover in Shed.

Table Showing the Actual Weighings, and Percentage of Loss in Weight, of Experimental Heap (No. II.) Fresh Farm-Yard Manure Under Shed, at Different Periods of the Year.

Weight Loss in Percentage of original of Loss.

Manure weight in Lbs. in Lbs. ------------------------------------+--------+--------+---------- Put up on the 3d of November, 1854 3,258 Weighed on the 30th of April, 1855, or after a lapse of 6 months 1,613 1,645 50.4 Weighed on the 23d of August, 1855, or after a lapse of 9 months and 20 days 1,297 1,961 60.0 Weighed on the 15th of November, 1855, or after a lapse of 12 months and 12 days 1,235 2,023 62.1 ------------------------------------+--------+--------+----------

It will be seen that 100 tons of manure, kept in a heap under cover for six months, would be reduced to 49.6-10 tons. Whereas, when the same manure was fermented for the same length of time in the open air, the 100 tons was reduced to only 71.4-10 tons. The difference is due princ.i.p.ally to the fact that the heap exposed contained more water, derived from rain and snow, than the heap kept under cover. This, of course, is what we should expect. Let us look at the results of Dr.

Vlcker's a.n.a.lyses:

Table Showing the Composition of Experimental Heap (No. II.) Fresh Farmyard Manure Under Shed, in Natural State at Different Periods of the Year.

-------------------------+--------+--------+--------+--------+-------- When put Feb. 14, Apr. 30, Aug. 23, Nov. 15, up, Nov. 1855. 1855. 1855. 1855.