<v; YPTTAfl AGHICULTLI! i:. 



Living in the tissue of the plant, the micro-organism 

 takes the nitrogen gas which has entered the plant root 

 and unites it with other bodies to form compounds which 

 are taken by the leguminous plant to build up its body. 

 On the other hand the bacteria derive their mineral and 

 other food from the sap of the plant with which they are 

 living. On account of the manufacturing power of their 

 lodgers, the bacteria, the leguminous plants are inde- 

 pendent of the soil for a supply of nitrates. Such crops 

 can therefore be grown on sandy soil devoid of organic 

 matter where barley or any other crop would fail through 

 lack of nitrogenous food. The farmer does not think of 

 the help he is obtaining from these little bacteria, but he 

 knows the enriching effect of growing berseem, beans, 

 lentils and earthnuts, and in every rotation the nitrogen - 

 collecting crops find a prominent place. 



The following determinations of nitric nitrogen will 

 show how, in bare land, available nitrogen is ever being 

 made, but that if the land is flooded this food may be 

 washed away. 



The bacteria in the soil may be divided into three classes ; 

 those which have no effect on soil fertility, those which 

 have a good effect and those which have a bad effect. 



