ii FOOD OBTAINED BY THE PLANT FROM SOIL 19 



up by the roots along with the water. Some of them 

 may be of no use to the plant, but others are used by 

 the plant in building up root, stem, and leaves. 



While a vigorous growth is taking place on the 

 soil this dissolved food is made good use of ; but in 

 autumn and winter, when the ground is bare, certain 

 kinds of valuable food are washed through the soil 

 and into the drains. 



It is for this reason that the farmer often sows a 

 catch crop, as it is called, of Italian rye grass or some 

 other forage crop, which, coming up in September or 

 October, occupies the surface and sucks up the food 

 in the soil. In the spring this catch crop is ploughed 

 in as green manure, and, rotting, returns to the soil 

 the food, stored in it through the winter, in time to 

 feed the young plants which are sown in spring. 



We have now learnt that there are certain 

 substances in the soil, soluble in water, which 

 are absorbed by the roots and are used as 

 food for the plant. 



