ch. x] Seed-Mixtures 173 



and "top" grasses should always be represented. In practice 

 very little difference can be made between mixtures for meadow 

 and pasture land, as it is of far more importance to consider soil 

 conditions first. Under constant grazing the low-growing species 

 such as Perennial Rye-grass, Crested Dog's-tail, White Clover, etc. 

 are most encouraged; whilst constant mowing favours the 

 taller plants such as Tall Oat-grass, Cock's-foot, Meadow Foxtail, 

 etc. 



In all permanent grass mixtures each of the following class of 

 plants should be represented : 



(a) Nitrogen accumulators, i.e. Leguminous plants. 



(b) Rapid soil coverers, e.g. Italian and Perennial Rye-grass. 



(c) Short-lived perennials, e.g. Timothy, Tall Oat, etc. 



(d) Permanent species, e.g. Meadow Foxtail, Cock's-foot, etc. 



(e) Bottom growing plants, e.g. Poas, Dog's-tail, etc. 

 (/) Early and late maturing species. 



Having selected the species, the next question that arises is 

 How much seed is it necessary to sow to secure good results at 

 reasonable outlay? 



The determination of the number of seeds required to sow an 

 acre is complicated in many ways as it varies so largely with the 

 soil, climate, etc. On some of the finest old English pastures it 

 has been calculated that there are at least twenty million plant 

 rootings per acre, and on new pastures where the turf is com- 

 paratively thin there are frequently ten or twelve million plants 

 per acre. Looking at the matter theoretically it may be presumed 

 that one plant per square inch (6,272,640 per acre, a large pro- 

 portion of which would form several distinct rootings) would be 

 sufficient to form a thick turf. Owing to adverse conditions, 

 however, the death-rate of seedlings is generally so high that in 

 practice it is often necessary to sow at least three times this 

 number of germinating seeds for permanent grass. 



Compounding of Mixtures. 



In Table I will be found the minimum, maximum, and average 

 number of seeds per pound of the different species, and in Table II 

 the weight and number of seeds necessary to sow one acre of land 

 under favourable conditions. , 



