DISTINCTIVE CHARACTERISTICS OF CHOI'S. 07 



dition for producing a crop of wheat. The growth of 

 leguminous crops is the most important means which 

 a farmer possesses for enriching his arable land with 

 nitrooen. 



The ploughing in of green crops has some advantages 

 over the feeding of crops on the land. By this mode of 

 proceeding the whole of the crop is returned to the soil, 

 whereas in feeding a small part of the nitrogen and ash 

 constituents is retained by the animal. The characteristic 

 advantage of green manuring lies, however, in the large 

 amount of humus which the soil acquires. All the carbon 

 which the crop has obtained from the atmosphere is in 

 this case incorporated with the soil, instead of being con- 

 sumed by the animal. Green manuring is thus especially 

 adapted for light sandy soils which need humus to in- 

 crease their retentive power. It is employed with great 

 advantage to fertilise barren soils in hot climates. 



Having glanced at the general advantages to be de- 

 rived from alternating green crops with cereals, we will 

 consider next the characteristics of different crops which 

 specially fit them to succeed or prepare for each other. 



Distinctive Characteristics of Crops. Differences in 

 their periods of growth occasion a marked distinction in 

 the relation of different crops to soil nitrogen. Thus the 

 fact that the active growth of the cereals commences in 

 spring, and concludes at their time of blooming towards 

 the end of June, places these crops at a disadvantage as 

 to the supply of nitrates from the soil. The autumn aud 

 winter rains have frequently washed out the greater part 

 of the nitrates contained in the soil before the growth of 

 the cereal crop commences, and nitrification in the soil hus 



