OTHER LEGUMINOUS PLANTS. I05 



the humus soils of the prairie. The volcanic soils of 

 the Rocky mountain valleys and the alluvial soils in 

 many of the river bottoms in Montana, Washington 

 and Oregon have special adaptation for the produc- 

 tion of peas. Light, hungry sands are ill adapted to 

 pea culture. While the vines will grow immensely 

 in slough and marsh lands which rest on clay not 

 far distant from the surface, they do not fruit well 

 in these places, since the energies of the plant are so 

 much directed to the growth of vines. While it is 

 not necessary that soils should be very rich in order 

 to grow peas, they must be supplied with a fair 

 amount of potash and phosphoric acid and enough 

 nitrogen to give the crop a good start. The rest 

 they will gather from the air. 



Place in the Rotation. — When peas are grown 

 alone, the aim should be to have them precede a crop 

 that recjuires much nitrogen to perfect its growth; 

 for instance, a crop of wheat, since, as already inti- 

 mated, peas are nitrogen gatherers. When grown 

 in combination, almost any place in the rotation may 

 be assigned to this crop. As it is commonly sown 

 early in the season to provide green food, and is also 

 harvested at a correspondingly early period, it may 

 frequently be followed by a crop of rape or fall tur- 

 nips, and it may with much propriety be followed 

 by a crop of winter rye. 



Preparing the Soil. — This crop is more com- 

 monly grov/n as soiling food along with oats, 

 although it may also be grown in conjunction with 

 other kinds of grain. Wheat is not considered as 

 good as oats for being growm in combination with 

 peas, for the reason, first, that it matures less slowly 



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