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BIOLOGY AND HUMAN LIFE 



2. Water. Where conditions are otherwise quite favorable, 

 the quantity of water may determine the size or character of 

 the crop. In most farming we have no control whatever over the 

 supply of water, but the farmer can do a great deal to make 

 better use of the water he gets. For example, by planting his 

 seeds properly and packing the soil down just right he can 

 hasten the absorption of water by the seeds and thus hasten 



Fig. 210. Improved varieties of domestic birds 



their sprouting; or in hoeing he can heap the soil about the 

 bases of the plants so as to prevent too rapid evaporation and 

 get fuller use of the moisture. Where irrigation is used the 

 water is supplied to the fields or orchards in measured quan- 

 tities, so that fairly uniform conditions of growth can be assured. 

 3. Management. Each kind of crop must be planted early 

 to get as long a growing season as possible, or as early a market, 

 or some other advantage. On the other hand, there is danger in 

 planting too early ; control depends upon knowing all the impor- 

 tant facts. If the seeds are too near the surface, the seedlings 

 may dry up before they are well started ; if they are too deep, 

 the young plant uses up too much of its food reserve in reaching 



