WEIGHT OF SEED TO BE USED 567 



species of plants to be employed for a particular ' ley,' and the 

 amount or area of the ground to be covered by each, it is 

 necessary to calculate the weight of seed required to cover the 

 ground to the desired extent before the actual sowing can 

 be carried out. This can readily be done if the weight of seed 

 of each species necessary to sow an acre completely, is known ; 

 for suppose it has been ascertained that 20 lbs. of cocksfoot seed 

 is sufficient to sow a complete acre, to sow say 15 per cent, of 

 this area will require T^nj^^s °f 2° ^^^-i ^^^ '^' 3 ^'^- °f seed. 



Below is a table giving the number of pounds of seed of each 

 species of grass and clover necessary to sow one acre, the sample 

 of seeds assumed to be absolutely pure and of 100 per cent, 

 germination capacity. 



The table is based on the assumption that 5,000,000 of 

 the larger grass and clover seeds are sufficient to sow an acre, 

 that is about 115 per square foot; but in the case of the smaller 

 seeds such as sheep's fescue, timothy, the meadow-grasses, 

 Alsike and white clovers, it is assumed that 10,000,000 are needed 

 to cover an acre (about 230 per square foot) sufficiently. 



Where the seeds are not pure and the germination capacity is 

 less than 100 per cent., the number of lbs. required to give the 

 necessary 5 or 10 million plants will be greater than that given 

 in Column III. of the above table. The correction for purity 

 is, however, easily made by multiplying the number of lbs. 

 indicated in column III. of the table by 100, and dividing 

 by the percentage purity of the particular commercial sample 

 used; the correction for germination capacity is made in a 

 similar manner, by multiplying by 100 and dividing by the figure 

 representing the percentage germination capacity of the sample. 

 Thus, if the sample of Alsike clover we are using is of 98 per 

 cent, purity and 95 per cent, germination capacity, the number 

 of lbs. necessary to sow an acre will be not 17 lbs. as the table 

 states, but 17 X VV° x ^w = i^i lbs. 



Many authorities consider it necessary to add 50 per cent. 

 Xq the weights calculated from column III. of the table whep 



