11 
Of these 1 is the most tenacious and compact; the others, in their respective order, become lighter 
and looser. The loam (5) is the normal type of soil. The following are also referred to: — 
9. Clay marls containing 50—60°/o clay and 10—15°/o carbonate of lime 
10. Loamy marls . 35—50°/o ,, and 25—50°/o + ae 
11. Calcareous marls Fs 20—35°/o ,, and 50—75°/o ; ry ee 
12, Sandy marls i" 60—80°/o sand and 10—20°/o 3 AR. 
Nos. 9 and 10 approach the loams, while 11 and 12 are easily dried up by the sun, and the 
vegetation thereby burned and destroyed. 
The following are also distinguished: — 
13. Clayey calcareous soils. 17. Good sweet humus soils. 
14. Loamy me M 18. Peaty soils. 
15. Sandy i re 19. Rich heath soils. 
16. Gravelly or stony __,, 
Most soils contain humus, and according to the amount can be classified as follows : — 
a. Poor in humus, with 3°/o humus. 
b. Containing humus, with 3— 5°%/o __,, 
c. Humous, with 5—10°%/o 
d, Rich in humus, with 410—15°/o _,, 
e. Veryrichin humus, with 15 and more ,, 
A humous sandy loam, for example, means a sandy loam containing 5—10 °/o humus. A soil con- 
taining iron sufficient to give it a deep red colour, is called ferruginous ; if, in addition to the iron, 
it contains acid humus, it is a barren ferruginous soil. 
To indicate the amount of moisture, the following terms are used: — arid, dry, humid, moist, wet. 
According to their mode of formation, soils are either indigenous, the weathered products of the rocks 
upon which they lie; or alluvial i, e. transported from a distance. The terms fertile and barren are 
applicable to all kinds of soil. 
Substances removed from the soil — Manure. The data, given in the special descriptions 
under this head show that the different kinds of clover and leguminous plants remove from the soil much 
more potash, lime, and magnesia, than grasses. In the ash of the latter, however, the proportion of 
silica is much larger than in the former. It is not necessary to return to the soil all the substances 
removed from it, as some are present in abundance. In the manure, it is only necessary to returi: the 
nitrogen. phosphorie acid, potash, and, more rarely, lime. On soils of ordinary types, the humus aud 
the humus-forming constituents of the manure, are also of itiportance, and are always abundant in frm- 
yard manure. In order to determine experimentally what nutritive substance is absent, or present culy 
to a minimum extent in the soil, Hemrich*) recommends the following trials: — 
1* Plot: Potash. 
gnd , Gypsum. 
grt, Phosphoric acid (Superphosphate). 
4th, Nitrogen, in the form of dried blood ground into powder. 
Bt Potash and Phosphoric acid. 
6 ., Potash and Nitrogen. 
ie Phosphoric acid and Nitrogen. 
St |, Phosphoric acid, Nitrogen and Potash. 
gt ., Without manure. 
The substance applied to that plot, from which the largest yield is obtained, is at a minimum in 
the soil, If the largest yield is obtained from plots 1—4, only one nutritive substance is at a mini- 
*) Heinrich, Grundlagen zur Beurtheilung der Ackerkrume in Beziehung auf landwirthschaftliche Pflanzenproduction. 
Wismar, 1882. 
Soils. 
Manure. 
