72 THE PRINCIPLES OP AGRICULTURE 



but if the seed is in rows or hills, as maize or 

 garden vegetables, tillage should begin as soon 

 8S the plants have appeared. 



SUGGESTIONS ON CHAPTEB IV 



84a. Tillage is a specific or special word, and is much better 

 than the more general word culture, when one is speaking of the 

 stirring of the soil. The culture of a crop properly comprises 

 tillage, pruning, fertilizing, and other good care. 



85o. For the oi-igin of the word inter-tillage, see foot-note in 

 Roberts' "Fertility of the Land," p. 69. 



88a. It should be observed that surface tillage saves moisture 

 by preventing evaporation, not, as commonly supposed, by caus- 

 ing the soil to absorb moisture from the atmosphere. When 

 moisture is most needed, is the season in which the air is dryer 

 than the soil. 



89a. To illustrate the importance of air, select a thrifty 

 plant, other than aquatic plant, growing in a florist's pot, and 

 exclude all the air by keeping the soil saturated with water, or 

 even by keeping the bott(jm of the plant standiug deep in water, 

 and note the checking of growth, and, in time, the decline of the 

 plant. The remarks on draining (65, 78) show how undrained 

 soils are often saturated with water ; and no matter how much 

 raw material for plant-food may exist in such a soil, it is un- 

 available to the plant. The reader can now guess why crops are 

 poor and yellow on flat lands in wet seasons. On the importance 

 of air in soils, read Chapter ix. of King's "Soil." 



89&. On the effects and necessity of tillage, read Chapter ill. 

 in Roberts' "Fertility of the Land," and Chapter xii. in King's 

 "Soil." A most interesting diversion in this couuection is a 

 perusal of Jethro Tull's famous book on "Horse-Hoeing Hus- 

 bandry" (53c). Copies of Cobbett's edition may frequently be 

 found in antiquarian book stores. 



91a. The trench left by the plow is a furrow. The earth 



