HAPPY INDIA 75 



kind may effect great benefit. But on those lands 

 which are not annually enriched by the deposits 

 of a flooding river it is absolutely essential, if the 

 fertility of the soil is to be maintained, that manure 

 should be added to the land. 



The reason is this : The crop of corn that is taken 

 from the land contains materials which are taken 

 out of the land, such as nitrogen, phosphoric acid, 

 potassium, as well as other things more common 

 and less likely to be depleted. These things are 

 essential to the growth of the plant, and after a 

 crop has been repeated for a good many years the 

 soil gets impoverished and good crops can no longer 

 be obtained. Some nitrogen is brought into the 

 soil every year by the rain, but that is not enough 

 to compensate for the amount taken out in the crop. 

 Nitrogen may be restored to the soil by growing 

 crops of a certain kind which extract nitrogen from 

 the air and deposit it in the soil. In India it is a 

 common thing to grow green crops, which whilst 

 green are ploughed into the ground and supply the 

 land with nitrogen. In England, Germany, France, 

 and many other countries it is customary to supply 

 the nitrogen in some mineral form, such as nitrate 

 of soda obtained from Chili, or sulphate of ammonia 

 obtained from gasworks and coke ovens. Without 

 this supply of nitrogen the crops of England and 

 other parts of Europe would rapidly decline. 

 Another most important mineral is potassium, that 

 is essential to the growths of plants. In Germany 

 there are great mines where salts of potassium are 



