A thousand pounds of wheat, 162/3 bu., and 2000 lb. of straw (an average crop per acre) require 27 lb. of nitrogen, 12.4 lb. of phosphoric acid, 17.9 lb. of potash. Ten tons of fresh unrotted manure from horses and cattle fed a moderate grain ration contain 136 lb. of nitrogen, 44 lb. of phosphoric acid, 120 lb. of potash. In farm practice it is estimated that the first crop grown after manuring may utilize, under favorable conditions, one-half of the plant-food contained in the manure applied. The plant-food available in ten tons of good fresh manure is: nitrogen 68 lb., phosphoric acid, 22 lb., potash, 60 lb. Thirty bushels of wheat and 2600 lb. of straw require, approximately, 46 lb. of nitrogen, 21 lb. of phosphoric acid, and 27 lb. of potash (Roberts).

Manures are frequently wasted by being applied too liberally. It is not economical, except for special crops or special conditions, to apply as much as thirty to forty two-horse loads or tons per acre at one time. For usual farm purposes, ten to twenty tons, or ten to twenty two-horse loads, is a liberal application per acre. It is best to apply it as it is made, if the land is not in a growing crop. The manure should be spread directly from the wagon, or a manure-spreader be used.

Commercial value (Roberts).

The value of manure in the following tables is determined by investigation during the winter months, and the nitrogen, phosphoric acid, and potash are computed at 15, 6, and 4 1/2 cents per pound, respectively (see prices, p. 47). The indirect benefits of manures may be considered an equal offset for the slightly less availability of their plant-food constituents as compared with fertilizers: —

Kind of Manure                                                                              Value per Ton

Sheep..................    $2.30

Calves..................      2.17

Pigs       ..................      2.29

Cows..................      2.02

Horses..................      2.21

Limited amounts of bedding were used in the tests from which the above figures were made. The plant-food in straw is not so quickly available as it is in the excrement of animals.

The following table exhibits the value of manure from different animals of average or aggregate weight of 1000 pounds: —

Kind of Animals                                                                           Value per Year

Fowls..................    $51.10

Sheep..................      26.09

Calves.................      24.45

Pigs..................      60.88

Cows....................      29.27

Horses.................      27.74

Manurial value of a ton of the usual bedding material computed as above:—

 

Nitrogen

Phosphoric Acid

Potash

Total

Barley straw ...

$1.65

$0.34

$1.74

$3.73

Oats.......................

1.38

0.33

1.59

3.30

Rye......

1.47

0.30

0.77

2.54

Wheat.....

1.44

0.26

0.57

2.27

Losses by leaching (Roberts).

Manures exposed at Ithaca in loose heaps of two to ten tons for six months showed loss of values as follows: —                               Per

1889  horse manure...................    42

1890  horse manure...................    62

1890 cow manure....................    30

1889 mixed manure (compacted)...............      9

In other cases, when small quantities of gypsum were mixed with the manure, the losses were notably diminished.