125 



TABLE II. 



Influence of CiUtural Methods on Tree Growth and Soil Moisture. 



(Average Increases in Trunk-girth 1908-1913, the first 6 jts. 



Expt. 331.) 



Average Gain over Av. Moisture Rel. to 

 Plat Treatment Increase Tillage alone Sept. 1913 optimum 



in. per ct. per ct. per ct. 



In this case again the untilled, mulched and spade- 

 planted trees have shown decidedly the best average 

 growth. They also have developed by far the most blos- 

 soms and they would doubtless have borne a lair amount 

 of fruit during the past season had it not been killed by the 

 imusually late and serious frosts. The addition of a mulch 

 alone has given a gain in tree growth of more than 21 per 

 cent over the trees receiving annual tillage alone. On the 

 same basis, the further addition of manure or a "complete'* 

 fertilizer shows an additional gain of about 10 per cent 

 more than the mulch alone. 



In this ease, therefore, it appears that moisture conser- 

 vation, which is the chief accomplishment of the mulch, is 

 about twice as important in trees of this age as the applica- 

 tion of plant food. Fully half the benefit shown in plat 5 

 is also doubtless a result of the mulching effect of the ma- 

 nure, though this does not appear in the present moisture 

 column chiefly because in 1913 the mulching effect was pur- 

 posely eliminated so far as possible by removing the accu- 

 mulations from around the trees and working them into the 

 soil. 



While the mulched trees are doing so well, those re- 

 ceiving annual tillage alone are making the least growth of 

 all, and the addition of a covercrop has improved it by less 



