No. 6. DEPARTMENT OF AGRICULTURE. 463 



As a broad general rule, the broad-leaved plants and those which 

 do not throw their roots deeply into the earth require more moisture 

 in proportion to the dry matter contained in them than the finer- 

 leaved plants, than those with less leaf surface and whose roots pene- 

 trate more deeply into the soil. For example, plants belonging to 

 the grass family, as the grasses, useful for hay, and cereal grains, 

 which do not present so large a leaf surface, and whose roots have a 

 tendency to go d"eep into the earth, do not use up the moisture as 

 rapidly as the legumes, or many of the vegetables, which have a 

 larger leaf surface. The latter require the maximum amount of 

 moisture in the soil, and sulfer seriously immediately there is any 

 lack. 



While the total amount of water used may be the same for dif- 

 ferent i)lauts, the time required for their growth and maturity 

 must also be considered. A crop of wheat, for example, because it 

 requires a longer season for full maturity may obtain its necessary 

 moisture, though the soil contained too low a percentage to enable 

 a potato crop, which grows and matures quickly, to obtain a full 

 supply; a short drouth would not materially injure the wheat while 

 it might ruin the potato crop, because of the difference in the length 

 of the period occupied in the growth of two crops. 



Where the object of the growth is succulence, and the leaf or 

 root constitutes the crop, as in the case of many vegetables, as let- 

 tuce, beets, etc., an abundant and continuous supply of moisture is 

 of greater relative importance than where the object is maturity, 

 and the seed constitutes the crop, because any delay in growth in 

 the former caused by lack of moisture is accompanied by a reduction 

 in quality, as well as yield; whereas, in the case of wheat or other 

 cereals the influence of delays in growth are more readily overcome, 

 besides the yield rather than quality is affected. These considera- 

 tions are useful in suggesting kinds of crops to grow under condi- 

 tions of known rainfall. 



A caieful review of the principles here pointed out shows the im- 

 portance of adopting and using methods that will aid as far as possi- 

 ble in retaining in the soil the moisture necessary for the growing 

 plant; or in other words, to so direct it that it may pass through the 

 plant into the atmosphere, rather than directly into it from the 

 surface of the soil. 



Conserving Moisture. 



To do this, is called ^'conserving moisture," and many of the opera- 

 tions of the farm, which are now carelessly performed, which result 

 in useless losses of moisture, may be changed so as to make them 

 assist very materially in saving it for the use of the crop, and while 



