132 



ing something that cannot be fully equalled by the mulch. 

 Their plant-food value may be coming more to the front in 

 this soil and with trees of this age, where the cropping strain 

 has been fully developed and plant food has also been with- 

 drawn for many years in the annual wood production. 



In the other treatments, however, where definite 

 amounts of plant food have been added to both cultural 

 methods, the superiority in yields is still with the mulched 

 trees. The advantage in one case amounts to more than 26 

 bushels per acre annually and in the other to nearly 125 

 bushels. This evidently makes it possible to continue or- 

 chards under the mulch treatment without loss of efficiency 

 even after full maturity is reached, provided sufficient ma- 

 terials are available and a proper fertilizer is used- 



As indicated in the table, the tree growth in this experi- 

 ment has been rather decidedly greater throughout, under 

 the tillage and covercrop treatment. In fact, it is quite 

 possible that too much growth is being made by these trees 

 in some cases. In any event, a large growth is generally 

 objectionable in, mature trees, and it is the growth that is 

 associated with the highest average yields that counts. 



Relation of Cultural Methods and Fertilization to Stead- 

 iness of Yields. — It is not sufficient to have a good crop 

 merely once in a while. It is the steady crop every year 

 that counts and enables one to develop and maintain his 

 reputation on the market. In this same experiment we have 

 a rather striking case of steady and uniform crops being 

 produced right alongside of the typical bi-ennial sort. This 

 appears in Table V, which shows the annual yields under 

 the various treatments during the past 7 years. 



As shown in the table, in all the tilled plats there has 

 been a well-defined biennial bearing habit, while in the 

 adjacent plats receiving a mulch and fertilization, the yields 

 have not only been steady but they have shown an almost 

 continuous increase. Tbe real cause of this difference is 

 not yet fully determined, but it is apparently connected 

 with three facts, — the presence of sufficient plant food, the 

 absence of excessive yields in any one year, and undisturbed 

 root-systems on the mulched trees. Judging from our other 

 similar data, none of these three conditions can be omitted 



