IV SELECTION OF PASTURE PLANTS 41 



Table I. — In the first column of Table I. are the numbers of lbs. of good 

 average commercial seeds required for a pure sowing of an acre ; and if the 

 percentage of pure and germinating seeds in any sample be lower or higher 

 than the average real value mentioned in column 4, more or less weight is 

 needed per acre. 



When seeds approximate in real value to the averages here fixed, that is to 

 say when they are of good average commercial quality, this Table may be 

 employed to save trouble, but otherwise Table IL will be found more 

 convenient. 



Table II. — Column i of Table II. gives the exact weights of perfectly 

 pure and germinating seeds (100 per cent, real value) needed per acre for a 

 pure sowing ; and from these figures the required quantity of any sample, of 

 which the real value is known, can be readily deduced. Suppose the real 

 value of a bag of Alsike clover to be 80 per cent, we know from column i 

 that 9 lbs. of perfectly pure and germinating seeds are necessary per acre ; 

 and the amount of 80 per cent. — quality seed to be used for the same area is 

 ascertained thus : — 



If of 100 per cent, pure and germinating seeds we sow per acre 9 lbs., 

 Then, of i ,, ,, ,, ,, ,, ,, 9 x 100 lbs. ; 



And of 80 ,, ,, ,, ,, ,, ,, ^—^ = ii-2Slbs. 



' 80 ■" 



Hence, the weight of any quality seed required to sow an acre of ground 

 may be quickly calculated by multiplying the weight of perfectly pure and 

 germinating seeds (100 per cent, real value) needed per acre for a pure sowing 

 (Column I, Table II.) by 100, and dividing the product by the real value of 

 the seed to be sown : or 



the required quantity per acre = 



/ Weight of pure and \ 

 germinating seed 

 required per acre 

 for a pure sowing. / 



/Real value of the 

 Vseed to be sown. 



-lbs. 



The quantities fixed by Column i are calculated for pure sowings, made in 

 good time on medium soil ; and they must not be regarded as invariable 

 under other conditions, since on rich, fertile and well-tilled land the plants 

 will tiller out more freely, and less seed is therefore required per acre ; while, 

 on the other hand, light, cold or bad soils and those in bleak, exposed 

 aspects or dry situations need additional weights of seeds per acre propor- 

 tionate to their inferiority to good medium land. In this connection the 

 preparation of the seed-bed is of so great importance that Stebler says a sowing 

 of 50 lbs. on a fine, firm, friable and level surface will yield better results than 

 100 lbs. on a cloddy and ill-prepared one, where many of the seeds would 

 fail to germinate. Then, too, late sowings in spring and autumn must be 

 more liberal than those made at more favourable seasons, because the young 

 plants will probably suffer to some extent from adverse weather, such as 

 drought or frost. 



We have seen that different pasture plants draw their sustenance from 

 different depths of the soil, and also that leguminous plants and grasses tax 

 the soil for different chemical constituents ; and from these premisses it is an 

 obvious deduction that a given area will profitably support a much greater 



