CULTURAL CARE. 



141 



those removed annually by the crop. Three other squares 

 are manured with two of these matters only alternating. 

 The crops are carefully weighed, and if one of the squares 

 with incomplete manure give a crop equivalent to that with 

 complete manure, or if the diiference between the value of 

 the crops is less, then the cost of the matter not used in the 

 square considered, we may assume that the soil is in a state 

 to furnish, at least temporarily, the required quantity of this 

 matter, and that it is, therefore, useless to add to the manure. 



Fig. 122. Arrangement of Experiments for ascertaining the relative value of 

 different forms of Manures in a given soil. 



Fig. 122 gives an idea of the arrangement of such an 

 experiment ; it is easy by a similar method to ascertain the 

 relative value of the different forms under which manures 

 can be applied. 



In the South of France the manures used are Stable 

 manure, sheep manure,night-soil,woollen ragsjiorns, old boots, 

 marc, bamboos, sea-weed, soot, and, finally, chemical manure. 



Stable manure contains per cent : 



Nitrogen 

 Phosphoric acid . . 

 Potash 



0-4 to 2-5 

 0-7 0-8 

 0-4 ,, 0-5 



Eight to 12 tons are applied per acre for four years ; straw is 

 added to it in very cold soils. 



Sheep-yard manures contain : 



Nitrogen 

 Phosphoric acid 



0-72 

 1-52 



They are richer than stable manures, and act quicker; that 

 is to say, their effect does not last as long. Six tons are 

 applied per acre every year. 



Night-soils vary greatly in composition, and are not 

 generally used for vines, because they are too strong, and 

 cause production of watery must, giving wines lacking in 

 keeping qualities. Their influence does not last more than 

 a year. This disadvantage may be diminished and better 

 effects obtained by mixing with tan, sawdust, peat-moss, or 

 sea-weeds. 



