PLANTS OF THE BRASSICA GENUS. I43 



the best yields are obtained north of the fortieth 

 parallel of north latitude. All the states of the Union 

 bordering on Canada, and likewise all the provinces 

 of Canada bordering on the United States, have high 

 adaptation, though not equally high, for the growth 

 of rape. In the states further south it ought to 

 be grown in the early part of the season, before the 

 weather becomes dry and hot, or in the autumn after 

 rain has begun to fall. In mild winter latitudes 

 this plant should be made to provide soiling food 

 through all or nearly all the winter. 



Rape also growsinfine forminthe higher Rocky 

 mountain valleys when it is irrigated, and sometime.^ 

 in the absence of irrigaton, but the great abundance 

 of the alfalfa crops in these makes, the growth of 

 rape less essential than it would otherwise be. The 

 highest adaptation for this plant will probably be 

 found on the Pacific coast from southern Oregon to 

 Alaska. The humidity of the climate there and the 

 mild character of the season makes it possible to 

 grow enormous crops of rape. 



Soil. — Rape will grow freely in any soil that 

 will produce a good crop of turnips, that is to say, 

 it will make a vigorous growth in deep, moist loam 

 soils, with a considerable mixture of sand in them. 

 It will also grow with even greater vigor in some 

 classes of soils not well adapted to rutabagas, as for 

 instance, the black humus soils found in sloughs, 

 and the muck soils of marshes, that have been 

 drained. It would probably be correct to say that in 

 these, rape finds its highest adaptation. It grows 

 luxuriantly in nearly all the varieties of soil found in 

 the prairies of the west, also in the sandy soils of the 



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