108 MASSACHUSETTS AGRICULTURE. 



by the stems and branches above, although they burrow below 

 the surface of the ground. On the contrary, they are fully as 

 sensitive to the extremes of moisture and dryness, or of heat 

 and cold. Nor is the access of air less important to one than 

 to the other ; both extremities of plants feed on air, the roots 

 more than the leaves. 



Hence it is that the condition of the air which circulates in 

 the ground, the temperature of the soil itself, and the moisture 

 contained therein, require to be regulated as well as tliat of the 

 atmosphere above ; and hence the importance that underground 

 climate should be thoroughly understood. For our land is not 

 merely wet but water-logged, all the space between the particles 

 of earth being filled with water, and consequently destitute of 

 air, except a small quantity which may be contained in the 

 water. By this means the plants are deprived of the most 

 essential part of their food. But when the water is removed, 

 air takes its place and holds in suspension sufficient moisture 

 for the roots to subsist upon, for it is not water in a fluid state 

 which plants in general prefer ; it is when it has assumed the 

 state of air-borne vapor, the best of all food for roots. Hence 

 it is evident that drainage produces a very important effect 

 upon land by raising its temperature and communicating heat 

 to the roots of plants. All practical farmers know the value of 

 this, as the soil requires to be heated in some degree for all 

 plants ; but some kinds demand a higher temperature than 

 others. 



The reason why drained land acquires an increased temper- 

 ature, is that water-logged land is always cold, and consists in a 

 well-known fact that heat cannot be transmitted downwards 

 through water. The nature of deep draining, then, is in fact 

 such as to change the underground climate by admitting an 

 additional access of air and warm rain to the roots of plants. 

 It is only when deep draining and deep trenching accompany 

 each other that much increased access of air to roots, beyond 

 what is customary, can be anticipated ; where both are secured 

 the effect on vegetation will certainly appear like magic, as the 

 Committee could readily see while viewing the three and one- 

 half acres offered for premium by Mr. Allis ; also showing to 

 the Committee the perseverance and good judgment of Mr. 

 Allis in under-draining, and thereby improving worthless land. 



