PERENNIAL FORAGE GRASSES 



33 



maximum yield is a sufficient and uniform stand of the grass 

 or grasses it is desired to grow. It is true that under favorable 

 conditions a comparatively few plants may produce a large 

 yield. (10) 



There are probably two reasons why a large stand is desirable. 

 There is a limit to which a single plant may be increased 

 through the use of a fertilizer, and hence the larger the number 

 of plants within certain limits the greater the total increase. 

 The second reason may be found in the fact that when the 

 plants are not sufficiently thick, other less desirable and smaller 

 yielding plants grow. By occupying the space and by taking 

 the available plant food at critical times such grasses reduce 

 the yield. 



The principles here enunciated are of great practical im- 

 portance in America. Over a large area, especially in the 

 North Central, the Western, and the Southern states, the chief 

 limiting factor in the production of perennial forage grasses 

 is the climatic conditions. The production of timothy is 

 limited to two tons per acre or less, principally by climatic 

 conditions. The addition of fertilizers, except in so far as 

 they may change the moisture content of the soil, is not likely 

 to have material effect in increasing the yield, although an in- 

 creased vigor of plants induced by fertilizers during a moist 

 period may have some effect. On the other hand, throughout 

 the northeastern part of the United States the climatic condi- 

 tions are extremely favorable to the growth of grasses. The 

 very climatic conditions which are favorable to the growth 

 of grasses are also favorable to a waste of the available plant 

 food of the soil; thus it is here that experimental evidence 

 shows marked influence from the use of fertilizers when applied 

 to grass lands. 



Commercially, two other factors enter into the use of fer- 

 tilizers namely, the cost of the fertilizers and the cost of the 

 product. Since the cost of transportation is high on both the 



