Page:1902 Encyclopædia Britannica - Volume 25 - A-AUS.pdf/244

 202

[united

AGRICULTURE

ture, determined by very large imports of grain, increasing more being retained in the straw, whilst the other products imports of meat and of other products of stock-feeding, of the rotation—the root and leguminous crops—which are supposed to be retained on the farm, contain very and very large imports of cattle-food and other agricultural also produce. More attention is thus being devoted to dairy much more potash than the cereals, and comparatively produce, not only on grass farms, but on those that are little of it is exported in meat and milk. Thus, the whole of the crops of rotation take up very much more of potash mainly arable. . . ! than of phosphoric acid, whilst probably even less of it is The benefits that accrue from the practice of rotation I ultimately lost to the land. Of lime, very little is taken are well illustrated in the results obtained from the investi- up by the cereal crops, and by the root-crops much less gations at Eothamsted into the simple four-course system, than of potash ; more by the leguminous than by the other which may fairly be regarded as a self-supporting system crops, and, by the clover especially, sometimes much more Reference may first be made to the important mineral than by all the other crops of the rotation put together. constituents of different crops of the four-course rotation. I Very little of the lime of the crops, however, goes off in the Of phosphoric acid, the cereal crops take up as much as, or i saleable products of the farm in the case of the selfmore than, any other crops of the rotation, excepting supporting rotation under consideration. Although, thereclover; and the greater portion thus taken up is l°st to : fore, different, and sometimes very large, amounts of these the farm in the saleable product—the gram. ihe typical mineral constituents are taken up by the various remainder, that in the straw, as well as that in the roots crops of rotation, there is no material export of any in the and the leguminous crops, is supposed to be retained on saleable products, excepting o/ phosphoric acid and of the farm, excepting the small amount exported m meat and potash; and, so far at least as phosphoric acid is conmilk. Of potash, each of the rotation crops takes up very cerned, experience has shown that it may be advantageously much more than of phosphoric acid. But much less potash ; supplied in purchased manures. than phosphoric acid is exported in the cereal grains, much Table XXIX. -The Weight and Average Composition of Ordinary Crops, in Pounds per PhosWeight of Crop. Total Nitro- Sul- Potash. Soda. Lime. MaF- Ii phoric nesia Pure gen. phur. I Acid. Crop. Ash. At Harvest. Dry. 3'6 | 14-2 1-0 0-6 9-3 27 34 30 1530 1,800 Wheat, grain, 30 bushels 3'5 i 6-9 8-2 2*0 19-5 5-1 16 142 2653 3,158 ,, straw 9'2 7T I 21T 2'6 7-8 28-8 50 4183 i 172 4,958 Total crop. 4-0 i 16-0 1-2 IT 9-8 235 46 1747 2,080 Barley, grain, 40 bushels 2-9 ! 4'7 8-0 3-9 25-9 314 111 2080 2,447 ,, straw 6-9 20-7 9'2 6T 35'7 5-0 49 382/ i 157 4,527 Total crop. 1-8 ; 3-6 13-0 0-8 9T 334 51 1625 1,890 Oats, grain, 45 bushels 9'8 ! 5T 1 6-4 4-6 37-0 418 140 2353 2,835 ,, straw. 8-7 19-4 8-0 46T I 5-4 11-6 52 3978 1 191 4,725 Total crop. 0-5 1I 3-4 10-0 0-2 6-5 28 22 1500 1,680 Maize, grain, 30 bushel ... ... 8-0 29-8 15 99 1877 2,208 ,, stalks, &c., 18-0 36-3 43 3377 121 Total crop. 9-2 32T 14-4 12-3 57 50-9 49 2822 203 3,360 Meadow hay, ton 5T 90T 28-2 24-9 9'4 83-4 98 3763 ! 258 4,480 Red Clover hay, 2 tons 4-4 24-3 42-9 0-6 78 58 1613 1,920 Beans, grain, 30 bushels 51-7 26-3 4-9 42-8 29 99 1848 2,240 ,, straw 9-9 i 29-1 2-3 29-2 9'3 67 T 4,160 ! 3461 ! 157 107 Total crop. 5-7 !! 22-4 61 15-2 108-6 17-0 25-5 3126 218 38,080 Turnips, root, 17 tons 3-8 10-7 7-5 48-5 5-7 40-2 49 1531 146 11,424 „ leaf 9-5 33-1 4657 ! 364 110 20-9 148-8 24-5 74-0 49,504 Total crop. 6-8 16-9 70 14-6 63-3 22-8 19-7 3349 163 31,360 Swedes, root, 14 tons 4-8 2-4 9-2 22-7 16-4 3-2 28 75 706 4,704 „ leaf. 9-2 21-7 98 17 •8'* 79-7 32-0 42-4 4055 238 36,064 Total crop. 4-9 222-8 69-4 15-9 18-3 36-4 98 5914 426 49,280 Mangels, root, 22 tons 9-1 77-9 49-3 27-0 24-2 16-5 51 254 1654 18,233 „ leaf 7568 680 149 14-0 300-7 118-7 42-9 42-5 52-9 67,513 Total crop. 3-4 6-3 21-5 3-8 2-7 76-5 46 3360 127 13,440 Potatoes, tubers, 6 tons
 * Calculated from a single analysis only.

Acre. Chlor- Silica. ine. 0T 2-4

0-6 96-3

2-5

96-9

0-5 3'6

11-8 56-8

4-1

68-6

0-5 6-1

19-9 65-4

6-6

85-3

0-2

0-5

14-6

56-9

9-8

7-0

1-1 4-3

0*4 6-9

5-4

7-3

1011-

2-6 5T

22-1

7-7

6-8 8-3

3T 8-6

15T

6-7

42-5 40-6

89-

83-1

17-9

4-4

Al

characteristically benefited by nitrogenous manures. The Of nitrogen, the cereal crops take up and retain much root-crops, indeed, may contain two, or more, times as less than any of the crops alternated with them, notwith- much nitrogen as either of the cereals, and the leguminous standing the circumstance that the cereals are very