216 DRY LAND FARMING 



that falls when properly managed. The clay loam soils 

 and the sandy loam soils underlaid with clay, and the 

 volcanic ash soils of the farther west, have very high 

 adaptation for growing wheat with reference, first, to the 

 food constituents which they contain ; second, with refer- 

 ence to the easy penetration by the roots of plants; and, 

 third, with reference to their ability to hold moisture. 

 The proportion of the arable land that is w r ell adapted 

 to the growth of wheat in the semi-arid west is unusually 

 large. 



Soils that are unsuitable for wheat include alkali 

 land, light coarse sands and soils that lie quite near the 

 underlying rock. Alkali lands are unsuitable in propor- 

 tion to the alkali and the degree of the same. Lands 

 strongly impregnated with black alkali are wholly un- 

 suited to the growth of wheat, and in fact all other crops, 

 and the same is true of those strongly impregnated with 

 white alkali. But small amounts of the latter are not 

 seriously prejudicial if indeed prejudicial at all. Light 

 and especially coarse sands will not sufficiently supply 

 the plants with food and moisture, hence the yields on 

 these will be small, and lands underlaid with rock near 

 the surface will not sustain good growth under dry con- 

 ditions. 



Plafce in the rotation. In dry areas, the place that 

 wheat will occupy in the rotation will depend upon many 

 conditions, such as the amount of the precipitation, the 

 degree of the plant food in the soil and the mechanical 

 condition of the same. Where the precipitation is about 

 20 inches, wheat crops may be grown from year to year 

 with reasonable success on many western soils for a more 

 or less limited number of years. The duration of these 

 is proportional to the amount of fertility in the land. 

 But the wisdom of such a rotation after two or three or 

 even a larger number of crops are taken in succession 

 after breaking the land, is to be questioned, because of the 



