Table Showing In Round Numbers The Quantities Of Nitrogen, Phosphoric Acid, And Potash Taken Out Of An Acre Of Soil By Various Crops

Crop.

Nitrogen.

Phosphoric Acid.

Potash.

lb.

lb.

lb.

Fruit crops ...

75

50

150

Mangels, 22 tons...

138

53

300

Beets, 14 tons...

68

31

142

Turnips, 17 tons...

112

33

148

*Turnips, 17 „...

187

74

426

Swedes, 14 „...

98

22

79

Beans (30 bus. grain) and straw ...

106

29

67

Oats, 45 bus. and straw

55

19

46

Wheat, 30 „ „

48

21

35

Bailey, 30 „ „

48

21

36

Maize, 20 „ „

43

18

36

Potatoes (6 tons, tubers)

47

22

76

*Potatoes(6 ,, „ )

119

55

192

Meadow hay, 1 1/2 tons..

49

12

51

Red clover, 2 „ ...

102

25

83

Hops ...

200

85

134

*Cabbage...

213

125

514

*Cauliflower ...

202

76

265

*Carrot.....

166

65

190

*Cucumber....

142

94

193

*Lettuce....

41

17

72

*Onion....

96

49

96

*Pea.........

153

39

69

It will thus be seen that such crops as Mangels, Turnips, Beans, Red Clover, and Hops absorb large supplies of nitrogen from the soil; and Mangels, Turnips, Beet, and Hops also drain the soil of large quantities of potash. It is noteworthy that such leguminous crops as Beans and Clover should take up such large quantities of nitrogen, notwithstanding the power they possess of fixing the nitrogen of the atmosphere (p. 127).

The figures for the crops marked with an asterisk are taken from Professor S. W. Fletcher's book on Soils, and relate to analyses at the Michigan Agricultural College. It would appear that according to the climate, and no doubt the methods of cultivation, the quantities of food taken from the soil would vary very much.