Talks On Manures A Series Of Familiar And Practical Talks Betwe

Chapter 53

Chapter 534,444 wordsPublic domain

KEEPING MANURE UNDER COVER.

Dr. Vœlcker, 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 principally 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. Vœlcker’s analyses:

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. |3, 1854.| | | | -------------------------+--------+--------+--------+--------+-------- Water | 66.17 | 67.32 | 56.89 | 43.43 | 41.66 * Soluble organic matter | 2.48 | 2.63 | 4.63 | 4.13 | 5.37 Soluble inorganic matter | 1.54 | 2.12 | 3.38 | 3.05 | 4.43 † Insoluble organic | | | | | matter | 25.76 | 20.46 | 25.43 | 26.01 | 27.69 Insoluble mineral matter | 4.05 | 7.47 | 9.67 | 23.38 | 20.85 +--------+--------+--------+--------+-------- |100.00 |100.00 |100.00 |100.00 |100.00 | | | | | * Containing nitrogen | .149 | .17 | .27 | .26 | .42 Equal to ammonia | .181 | .20 | .32 | .31 | .51 † Containing nitrogen | .494 | .58 | .92 | 1.01 | 1.09 Equal to ammonia | .599 | .70 | 1.11 | 1.23 | 1.31 Total amount of nitrogen | .643 | .75 | 1.19 | 1.27 | 1.51 Equal to ammonia | .780 | .90 | 1.43 | 1.54 | 1.82 Ammonia in free state | .034 | .022 | .055 | .015 | .019 Ammonia in form of salts | | | | | easily decomposed | | | | | by quicklime | .088 | .054 | .101 | .103 | .146 Total amount of organic | | | | | matter | 28.24 | 23.09 | 30.06 | 30.14 | 33.06 Total amount of mineral | | | | | substance | 5.59 | 9.59 | 13.05 | 26.43 | 25.28 -------------------------+--------+--------+--------+--------+--------

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

-------------------------+--------+--------+--------+--------+-------- |When put|Feb. 14,|Apr. 30,|Aug. 23,|Nov. 15, |up, Nov.|1855. |1855. |1855. |1855. |3, 1854.| | | | -------------------------+--------+--------+--------+--------+-------- * Soluble organic matter | 7.33 | 8.04 | 10.74 | 7.30 | 9.20 Soluble inorganic matter | 4.55 | 6.48 | 7.84 | 5.39 | 7.59 † Insoluble organic | | | | | matter | 76.15 | 62.60 | 58.99 | 45.97 | 47.46 Insoluble mineral matter | 11.97 | 22.88 | 22.43 | 41.34 | 35.75 +--------+--------+--------+--------+-------- |100.00 |100.00 |100.00 |100.00 |100.00 | | | | | * Containing nitrogen | .44 | .53 | .63 | .46 | .72 Equal to ammonia | .53 | .66 | .75 | .56 | .88 † Containing nitrogen | 1.46 | 1.77 | 2.14 | 1.78 | 1.88 Equal to ammonia | 1.77 | 2.14 | 2.59 | 2.16 | 2.26 Total amount of nitrogen | 1.90 | 2.30 | 2.77 | 2.24 | 2.60 Equal to ammonia | 2.30 | 2.80 | 3.35 | 2.72 | 3.08 Ammonia in free state | .10 | .067 | .127 | .026 | .033 Ammonia in form of salts,| | | | | easily decomposed | | | | | by quicklime | .26 | .165 | .234 | .182 | .250 Total amount of organic | | | | | matter | 83.48 | 70.64 | 69.73 | 53.27 | 56.66 Total amount of mineral | | | | | substance | 16.52 | 29.36 | 30.27 | 46.73 | 43.34 -------------------------+--------+--------+--------+--------+--------

The above analyses are of value to those who buy fresh and fermented manure. They can form some idea of what they are getting. If they buy a ton of fresh manure in November, they get 12¾ lbs. of nitrogen, and 30¾ lbs. of soluble mineral matter. If they buy a ton of the same manure that has been kept under cover until February, they get, nitrogen, 15 lbs.; soluble minerals, 42½ lbs. In April, they get, nitrogen, 23¾ lbs.; soluble minerals, 67½ lbs. In August, they get, nitrogen, 25½ lbs.; soluble minerals, 61 lbs. In November, when the manure is over one year old, they get, in a ton, nitrogen, 30¼ lbs.; soluble minerals, 88½ lbs.

When manure has not been exposed, it is clear that a purchaser can afford to pay considerably more for a ton of rotted manure than for a ton of fresh manure. But waiving this point for the present, let us see how the matter stands with the farmer who makes and uses the manure. What does he gain by keeping and fermenting the manure under cover?

The following table shows the weight and composition of the entire heap of manure, kept under cover, at different times:

Table Showing Composition of Entire Experimental Heap (No. II.) Fresh Farm-Yard Manure, Under Shed.

-------------------------------+---------+---------+---------+-------- |When put |April 30,|Aug. 23, |Nov. 15, |up, Nov. |1855. |1855. |1855. |3, 1854. | | | -------------------------------+---------+---------+---------+-------- | lbs. | lbs. | lbs. | lbs. Weight of manure | 3,258. |1,613. |1,297. |1,235. +---------+---------+---------+-------- Amount of water in the manure | 2,156. | 917.6 | 563.2 | 514.5 Amount of dry matter | 1,102. | 695.4 | 733.8 | 720.5 * Consisting of soluble | | | | organic matter | 80.77| 74.68 | 53.56 | 66.28 Soluble mineral matter | 50.14| 54.51 | 39.55 | 54.68 † Insoluble organic matter | 839.17| 410.24 | 337.32 | 341.97 Insoluble mineral matter | 131.92| 155.97 | 303.37 | 257.57 +---------+---------+---------+-------- | 1,102. | 695.4 | 733.8 | 720.5 | | | | * Containing nitrogen | 4.85| 4.38 | 3.46 | 5.25 Equal to ammonia | 5.88| 5.33 | 4.20 | 6.37 † Containing nitrogen | 16.08| 14.88 | 13.08 | 13.54 Equal to ammonia | 19.59| 17.46 | 15.88 | 16.44 Total amount of nitrogen | | | | in manure | 20.93| 19.26 | 16.54 | 18.79 Equal to ammonia | 25.40| 22.79 | 20.08 | 22.81 The manure contains ammonia | | | | in free state | 1.10| .88 | .19 | .23 The manure contains ammonia | | | | in form of salts, easily | | | | decomposed by quicklime | 2.86| 1.62 | 1.33 | 1.80 Total amount of organic matter | 919.94| 484.92 | 390.88 | 408.25 Total amount of mineral matter | 182.06| 210.48 | 342.92 | 312.35 -------------------------------+---------+---------+---------+--------

This is the table, as given by Dr. Vœlcker. For the sake of comparison, we will figure out what the changes would be in a heap of five tons (10,000 lbs.) of manure, when fermented under cover, precisely in the same way as we did with the heap fermented in the open air, exposed to the rain. The following is the table:

Contents of a Heap Of Manure at Different Periods. Fermented Under Cover.

It will be seen that the heap of manure kept under cover contained, on the 30th of April, _less_ soluble organic matter, _less_ soluble mineral matter, _less_ soluble nitrogenous matter, and _less_ total nitrogen than the heap of manure exposed to the weather. This is precisely what I should have expected. The heap of manure in the shed probably fermented more rapidly than the heap out of doors, and there was not water enough in the manure to retain the carbonate of ammonia, or to favor the production of organic acids. _The heap was too dry._ If it could have received enough of the liquid from the stables to have kept it moderately moist, the result would have been very different.

We will postpone further consideration of this point at present, and look at the results of another of Dr. Vœlcker’s interesting experiments.

Dr. Vœlcker wished to ascertain the effect of three common methods of managing manure:

1st. Keeping it in a _heap_ in the open air in the barn-yard, or field.

2d. Keeping it in a _heap_ under cover in a shed.

3d. Keeping it _spread out_ over the barn-yard.

“You say these are common methods of managing manure,” remarked the Deacon, “but I never knew any one in this country take the trouble to spread manure over the yard.”

“Perhaps not,” I replied, “but you have known a good many farmers who adopt this very method of keeping their manure. They do not spread it--but they let it lie spread out over the yards, just wherever it happens to be.”

Let us see what the effect of this treatment is on the composition and value of the manure.

We have examined the effect of keeping manure in a heap in the open air, and also of keeping it in a heap under cover. Now let us see how these methods compare with the practice of leaving it exposed to the rains, spread out in the yard.

On the 3rd of November, 1854, Dr. Vœlcker weighed out 1,652 lbs. of manure similar to that used in the preceding experiments, and spread it out in the yard. It was weighed April 30, and again August 23, and November 15.

The following table gives the actual weight of the manure at the different periods, also the actual amount of the water, organic matter, ash, nitrogen, etc.:

Table Showing the Weight and Composition of Entire Mass of Experimental Manure (No. Iii.), Fresh Farm-Yard Manure, Spread in Open Yard at Different Periods of the Year. In Natural State.

-------------------------------+---------+---------+---------+-------- |When put |April 30,|Aug. 23, |Nov. 15, |up, Nov. |1855. |1855. |1855. |3, 1854. | | | -------------------------------+---------+---------+---------+-------- | lbs. | lbs. | lbs. | lbs. Weight of manure |1,652. |1,429. |1,012. |950. +---------+---------+---------+-------- Amount of water in the manure |1,093. |1,143. | 709.3 |622.8 Amount of dry matter | 559. | 285.5 | 302.7 |327.2 * Consisting of soluble | | | | organic matter | 40.97 | 16.55 | 4.96 | 3.95 Soluble mineral matter | 25.43 | 14.41 | 6.47 | 5.52 † Insoluble organic matter | 425.67 | 163.79 | 106.81 | 94.45 Insoluble mineral matter | 66.93 | 90.75 | 184.46 |223.28 +---------+---------+---------+-------- | 559.00 | 285.50 | 302.70 |327.20 | | | | * Containing nitrogen | 3.28 | 1.19 | .60 | .32 Equal to ammonia | 3.98 | 1.44 | .73 | .39 † Containing nitrogen | 6.21 | 6.51 | 3.54 | 3.56 Equal to ammonia | 7.54 | 7.90 | 4.29 | 4.25 Total amount of nitrogen in | | | | manure | 9.19 | 7.70 | 4.14 | 3.88 Equal to ammonia | 11.52 | 9.34 | 5.02 | 4.64 The manure contains ammonia | | | | in free state | .55 | .14 | .13 | .0055 The manure contains ammonia | | | | in form of salts, easily | | | | decomposed by quicklime | 1.45 | .62 | .55 | .28 Total amount of organic matter | 466.64 | 180.34 | 111.77 | 98.40 Total amount of mineral matter | 92.36 | 105.16 | 190.93 |228.80 -------------------------------+---------+---------+---------+--------

“One moment,” said the Deacon. “These tables are a little confusing. The table you have just given shows the actual weight of the manure in the heap, and what it contained at different periods.” --“Yes,” said I, “and the table following shows what 100 lbs. of this manure, spread out in the yard, contained at the different dates mentioned. It shows how greatly manure deteriorates by being exposed to rain, spread out on the surface of the yard. The table merits careful study.”

Table Showing Composition of Experimental Heap (No. III.). Fresh Farm Yard Manure, Spread in Open Yard, at Different Periods of the Year. In Natural State.

-------------------------------+---------+---------+--------+--------- |When put |April 30,|Aug. 23,|Nov. 15, |up, Nov. |1855. |1855. |1855. |3, 1854. | | | -------------------------------+---------+---------+--------+--------- Water | 66.17 | 80.02 | 70.09 | 65.56 * Soluble organic matter | 2.48 | 1.16 | .49 | .42 Soluble inorganic matter | 1.54 | 1.01 | .64 | .57 † Insoluble organic matter | 25.76 | 11.46 | 10.56 | 9.94 Insoluble mineral matter | 4.05 | 6.35 | 18.22 | 23.51 +---------+---------+--------+--------- | 100.00 | 100.00 | 100.00 | 100.00 | | | | * Containing nitrogen | .149 | .08 | .06 | .03 Equal to ammonia | .181 | .69 | .07 | .036 † Containing nitrogen | .494 | .45 | .35 | .36 Equal to ammonia | .599 | .54 | .42 | .46 Total amount of nitrogen | .643 | .53 | .41 | .39 Equal to ammonia | .780 | .63 | .49 | .496 Ammonia in free state | .034 | .010 | .012| .0006 Ammonia in form of salts, | | | | easily decomposed by | | | | quicklime | .088 | .045 | .051| .030 Total amount of organic matter | 28.24 | 12.62 | 11.05 | 10.36 Total amount of mineral | | | | substance | 5.59 | 7.36 | 18.86 | 24.08 -------------------------------+---------+---------+--------+---------

The following table shows the composition of the manure, calculated dry:

Table Showing Composition of Experimental Heap (No. III.), Fresh Farm Yard Manure, Spread in Open Yard, at Different Periods of the Year. Calculated Dry.

-------------------------------+---------+---------+--------+--------- |When put |April 30,|Aug. 23,|Nov. 15, |up, Nov. |1855. |1855. |1855. |3, 1854. | | | -------------------------------+---------+---------+--------+--------- * Soluble organic matter | 7.33 | 5.80 | 1.64 | 1.21 Soluble inorganic matter | 4.55 | 5.05 | 2.14 | 1.69 † Insoluble organic matter | 76.15 | 57.37 | 35.30 | 28.86 Insoluble mineral matter | 11.97 | 31.78 | 60.92 | 68.24 +---------+---------+--------+--------- | 100.00 | 100.00 | 100.00 | 100.00 | | | | * Containing nitrogen | .44 | .42 | .20 | .10 Equal to ammonia | .53 | .51 | .24 | .12 † Containing nitrogen | 1.46 | 2.28 | 1.17 | 1.09 Equal to ammonia | 1.77 | 2.76 | 1.41 | 1.32 Total amount of nitrogen | 1.90 | 2.70 | 1.37 | 1.19 Equal to ammonia | 2.30 | 3.27 | 1.65 | 1.44 Ammonia in free state | .10 | .05 | .040| .0017 Ammonia in form of salts, | | | | easily decomposed by | | | | quicklime | .26 | .225 | .171| .087 Total amount of organic matter | 83.48 | 63.17 | 36.94 | 30.07 Total amount of mineral | | | | substance | 16.52 | 36.83 | 63.06 | 69.93 -------------------------------+---------+---------+--------+---------

I have made out the following table, showing what would be the changes in a heap of 5 tons (10,000 lbs.) of manure, spread out in the yard, so that we can readily see the effect of this method of management as compared with the other two methods of keeping the manure in compact heaps, one exposed, the other under cover.

The following is the table:

Contents of the Mass of Manure, Spread Out in Farm-Yard, and Exposed to Rain, Etc.

------------------------------+-----------+--------+---------+-------- |When |Apr. 30.|Aug. 23. |Nov. 15. |spread out,| | | |Nov. 3. | | | ------------------------------+-----------+--------+---------+-------- | lbs. | lbs. | lbs. | lbs. Total weight of manure | 10,000 | 8,350 | 6,130 | 5,750 Water in the manure | 6,617 | 6,922 | 4,297 | 3,771 Total organic matter | 2,824 | 1,092 | 677 | 595 Total inorganic matter | 559 | 636 | 1,155 | 1,384 Total nitrogen in manure | 64.3 | 45.9 | 25 | 22.4 Total soluble organic matter | 248 | 100 | 30 | 24 Insoluble organic matter | 2,576 | 992 | 647 | 571 Soluble mineral matter | 154 | 87 | 39 | 33 Insoluble mineral matter | 405 | 549 | 1,116 | 1,351 Nitrogen in soluble matter | 14.9 | 6.9 | 3.6 | 1.7 Nitrogen in insoluble matter | 49.4 | 39 | 21.4 | 20.7 ------------------------------+-----------+--------+---------+--------

It is not necessary to make many remarks on this table. The facts speak for themselves. It will be seen that there is considerable loss even by letting the manure lie spread out until spring; but, serious as this loss is, it is small compared to the loss sustained by allowing the manure to lie exposed in the yard during the summer.

In the five tons of fresh manure, we have, November 3, 64.3 lbs. of nitrogen; April 30, we have 46 lbs.; August 23, only 25 lbs. This is a great loss of the most valuable constituent of the manure. Of soluble mineral matter, the next most valuable ingredient, we have in the five tons of fresh manure, November 3, 154 lbs.; April 30, 87 lbs.; and August 23, only 39 lbs. Of soluble nitrogen, the most active and valuable part of the manure, we have, November 3, nearly 15 lbs.; April 30, not quite 7 lbs.; August 23, 3½ lbs.; and November 15, not quite 1¾ lbs.

Dr. Vœlcker made still another experiment. He took 1,613 lbs. of _well-rotted_ dung (mixed manure from horses, cows, and pigs,) and kept it in a heap, exposed to the weather, from December 5 to April 30, August 23, and November 15, weighing it and analyzing it at these different dates. I think it is not necessary to give the results in detail. From the 5th of December to the 30th of April, there was _no loss_ of nitrogen in the heap, and comparatively little loss of soluble mineral matters; but from April 30 to August 23, there was considerable loss in both these valuable ingredients, which were washed out of the heap by rain.

Dr. Vœlcker draws the following conclusions from his experiments:

“Having described at length my experiments with farm-yard manure,” he says, “it may not be amiss to state briefly the more prominent and practically interesting points which have been developed in the course of this investigation. I would, therefore, observe:

“1. Perfectly fresh farm yard manure contains but a small proportion of free ammonia.

“2. The nitrogen in fresh dung exists principally in the state of insoluble nitrogenized matters.

“3. The soluble organic and mineral constituents of dung are much more valuable fertilizers than the insoluble. Particular care, therefore, should be bestowed upon the preservation of the liquid excrements of animals, and for the same reason the manure should be kept in perfectly water-proof pits of sufficient capacity to render the setting up of dung-heaps in the corner of fields, as much as it is possible, unnecessary.

“4. Farm-yard manure, even in quite a fresh state, contains phosphate of lime, which is much more soluble than has hitherto been suspected.

“5. The urine of the horse, cow, and pig, does not contain any appreciable quantity of phosphate of lime, whilst the drainings of dung-heaps contain considerable quantities of this valuable fertilizer. The drainings of dung-heaps, partly for this reason, are more valuable than the urine of our domestic animals, and, therefore, ought to be prevented by all available means from running to waste.

“6. The most effectual means of preventing loss in fertilizing matters is to cart the manure directly on the field whenever circumstances allow this to be done.

“7. On all soils with a moderate proportion of clay, no fear need to be entertained of valuable fertilizing substances becoming wasted if the manure cannot be plowed in at once. Fresh, and even well-rotten, dung contains very little free ammonia; and since active fermentation, and with it the further evolution of free ammonia, is stopped by spreading out the manure on the field, valuable volatile manuring matters can not escape into the air by adopting this plan.

“As all soils with a moderate proportion of clay possess in a remarkable degree the power of absorbing and retaining manuring matters, none of the saline and soluble organic constituents are wasted even by a heavy fall of rain. It may, indeed, be questioned whether it is more advisable to plow in the manure at once, or to let it lie for some time on the surface, and to give the rain full opportunity to wash it into the soil.

“It appears to me a matter of the greatest importance to regulate the application of manure to our fields, so that its constituents may become properly diluted and uniformly distributed amongst a large mass of soil. By plowing in the manure at once, it appears to me, this desirable end can not be reached so perfectly as by allowing the rain to wash in gradually the manure evenly spread on the surface of the field.

“By adopting such a course, in case practical experience should confirm my theoretical reasoning, the objection could no longer be maintained that the land is not ready for carting manure upon it. I am inclined to recommend, as a general rule: Cart the manure on the field, spread it at once, and wait for a favorable opportunity to plow it in. In the case of clay soils, I have no hesitation to say the manure may be spread even six months before it is plowed in, without losing any appreciable quantity in manuring matter.

“I am perfectly aware, that on stiff clay land, farm-yard manure, more especially long dung, when plowed in before the frost sets in, exercises a most beneficial action by keeping the soil loose, and admitting the free access of frost, which pulverizes the land, and would, therefore, by no means recommend to leave the manure spread on the surface without plowing it in. All I wish to enforce is, that when no other choice is left but either to set up the manure in a heap in a corner of the field, or to spread it on the field, without plowing it in directly, to adopt the latter plan. In the case of very light sandy soils, it may perhaps not be advisable to spread out the manure a long time before it is plowed in, since such soils do not possess the power of retaining manuring matters in any marked degree. On light sandy soils, I would suggest to manure with well-fermented dung, shortly before the crop intended to be grown is sown.

“8. Well-rotten dung contains, likewise, little free ammonia, but a very much larger proportion of soluble organic and saline mineral matters than fresh manure.

“9. Rotten dung is richer in nitrogen than fresh.

“10. Weight for weight, rotten dung is more valuable than fresh.

“11. In the fermentation of dung, a very considerable proportion of the organic matters in fresh manure is dissipated into the air in the form of carbonic acid and other gases.

“12. Properly regulated, however, the fermentation of dung is not attended with any great loss of nitrogen, nor of saline mineral matters.

“13. During the fermentation of dung, ulmic, humic, and other organic acids are formed, as well as gypsum, which fix the ammonia generated in the decomposition of the nitrogenized constituents of dung.

“14. During the fermentation of dung, the phosphate of lime which it contains is rendered more soluble than in fresh manure.

“15. In the interior and heated portions of manure-heaps, ammonia is given off; but, on passing into the external and cold layers of dung-heaps, the free ammonia is retained in the heap.

“16. Ammonia is not given off from the surface of well-compressed dung-heaps, but on turning manure-heaps, it is wasted in appreciable quantities. Dung-heaps, for this reason, should not be turned more frequently than absolutely necessary.

“17. No advantage appears to result from carrying on the fermentation of dung too far, but every disadvantage.

“18. Farm-yard manure becomes deteriorated in value, when kept in heaps exposed to the weather, the more the longer it is kept.

“19. The loss in manuring matters, which is incurred in keeping manure-heaps exposed to the weather, is not so much due to the volatilization of ammonia as to the removal of ammoniacal salts, soluble nitrogenized organic matters, and valuable mineral matters, by the rain which falls in the period during which the manure is kept.

“20. If rain is excluded from dung-heaps, or little rain falls at a time, the loss in ammonia is trifling, and no saline matters, of course, are removed; but, if much rain falls, especially if it descends in heavy showers upon the dung-heap, a serious loss in ammonia, soluble organic matter, phosphate of lime, and salts of potash is incurred, and the manure becomes rapidly deteriorated in value, whilst at the same time it is diminished in weight.

“21. Well-rotten dung is more readily affected by the deteriorating influence of rain than fresh manure.

“22. Practically speaking, all the essentially valuable manuring constituents are preserved by keeping farm-yard manure under cover.

“23. If the animals have been supplied with plenty of litter, fresh dung contains an insufficient quantity of water to induce an active fermentation. In this case, fresh dung can not be properly fermented under cover, except water or liquid manure is pumped over the heap from time to time.

“Where much straw is used in the manufacture of dung, and no provision is made to supply the manure in the pit at any time with the requisite amount of moisture, it may not be advisable to put up a roof over the dung-pit. On the other hand, on farms where there is a deficiency of straw, so that the moisture of the excrements of our domestic animals is barely absorbed by the litter, the advantage of erecting a roof over the dung-pit will be found very great.

“24. The worst method of making manure is to produce it by animals kept in open yards, since a large proportion of valuable fertilizing matters is wasted in a short time; and after a lapse of twelve months, at least two-thirds of the substance of the manure is wasted, and only one-third, inferior in quality to an equal weight of fresh dung, is left behind.

“25. The most rational plan of keeping manure in heaps appears to me that adopted by Mr. Lawrence, of Cirencester, and described by him at length in Morton’s ‘Cyclopædia of Agriculture,’ under the head of ‘Manure.’”