HOW TO PREPARE AND FERTILIZE LAND 15 



additional value of supplying humus, 

 which lightens the soil, increasing its 

 power to hold water. It also assists in 

 liberating the mineral substances in the 

 soil. If the manure is coarse, it should 

 be rotted to increase its availability 

 before applying. There are three elements 

 necessary to supply to the soil: nitrogen, 

 potash and phosphoric acid. Farm ma- 

 nures supply all of these, but not always 

 in the proportion needed. 



Commercial fertilizers can be bought 

 and applied separately or in combination. 

 It must always be remembered that they 

 are very powerful and should never be 

 placed in contact with roots or seeds, but 

 should be mixed with the soil. 



Nitrates stimulate the vegetable system 

 and tend to produce dark-green foliage. 

 The application of too much nitrogen has 

 a tendency to make the plant "run to 

 leaves" at the expense of flowers and 

 fruit. A lack of nitrogen is shown by 

 weak growth of a yellowish-green colour. 

 Nitrate of soda and sulfate of ammonia are 



