326 SYSTEMS OF MANURING CROPS [chap. 



the corn crop. The potash salts (4 cwts. per acre of 

 kainit), being soluble, can be kept until the autumn or 

 winter. Beyond this it is not wise to use fertilisers on 

 these crops ; a little nitrate of soda may serve to give 

 the young plant a start in its first spring, and a coat of 

 dung is often valuable, but the proper way to regard 

 lucerne or sainfoin is as a cheap means of enriching the 

 land with a minimum of expenditure. 



Vetches, Trefoil, Crimson Clover, and similar rapidly 

 growing leguminous crops are usually grown as catch 

 crops on land that is already in good heart and do not 

 require any fertiliser. Lupins are sometimes grown on 

 poor sandy land in order to be ploughed in as green 

 manure ; in such a case the preparation of the land 

 (supposing it to be poor heathy land undergoing 

 reclamation) should include the application of 4 to 5 

 cwts. per acre of basic slag and 3 to 4 cwts. of kainit to 

 supply the lupins with the necessary mineral food, for 

 without it they could neither gather nitrogen nor 

 accumulate humus for the amelioration of the soil. 



Grass Land. — In considering the effect of manures 

 upon the grass crop, we have to take into account not 

 only the weight of the produce but the character and 

 botanical composition of the herbage that ensues. 

 Every meadow possesses a characteristic vegetation 

 made up of various species of grasses, a few leguminous 

 plants like white and red clover, bird's foot trefoil, the 

 yellow vetchling, etc., and sundry miscellaneous species 

 which are, in the main, of little value to stock and may 

 be classed as weeds. The proportion which each of 

 these species contributes to the herbage represents the 

 degree to which it is suited by the various conditions of 

 food, water, soil, texture, etc., which prevail in that field. 

 A strenuous competition is going on between the 

 different species, each of which is endeavouring to 



