TREATMENT OP COLD SOILS. 137 



ctrable to the plough in pasture 

 or waste lands which it is designed 

 to clear up. In such cases a stout | 

 grapple represented in figure 4 is 

 found extremely useful in remov 

 ing the surface which may be Fig. 4. 

 burned previous to ploughing. 



424. Much land is so situated as to require thorough 

 draining before it can be cultivated at all to advantage. 

 The object of draining is to remove an excess of moisture 

 from the soil. 



425. Water standing stagnant in the soil diminishes 

 the good effects of manures very much by preventing 

 decomposition, makes it impossible to work lands early in 

 the spring, prevents seeds from germinating, or makes 

 them germinate more slowly, and delays the ripening of 

 crops, lessening their quantity and making their quality 

 inferior. 



426. An excess of water in the soil also excludes the 

 air. This is injurious, because the air does much to pro 

 mote the chemical changes in the mineral parts of the 

 earth which are necessary to the growth of plants, and 

 converts the organic materials in the soil into vegetable 

 acids which give it the name of &quot; sour&quot; or &quot;cold&quot; soil. 



427. Drainage is effected either by opening channels 

 on the surface, or by means of covered drains. Open 

 drains are sometimes very useful, but are liable to serious 

 objections. The water which enters them, carries with it 

 many of the substances which make the soil fertile, which 

 are thus lost. Besides, such drains arc not nearly as 

 useful as covered ones, while they interfere with a proper 

 cultivation ; they leave a great deal of water in the soil, 

 weeds are very apt to grow along their sides, and they 



