4 N. H. AGR. EXPERIMENT STATION. [Bulletin 168 



the home test. In all lines of soil fertility work, whether it be 

 on the cereal crop, hay land, or some specialized crops the investi- 

 gators have usually been of the opinion that the home fertilizer 

 test led to the only safe and reliable information that could be 

 obtained. Some general information has been secured through 

 long time tests that is applicable over rather large areas, but this 

 has often been misused and misquoted for the benefit of biased 

 persons or commercial concerns. There can be little doubt that 

 much fertilizer has been used in the orchard and on the farm that 

 has been of no value to the land or crops; however, there are 

 doubtless many sections where the sins of omission have been far 

 greater than the sins of commission. But it is to be hoped that 

 such valuable data as have appeared in the past few years will 

 ultimately lead to a common agreement regarding our orchard 

 policies for various conditions. The fact that fruit trees have 

 not responded to artificial fertilizers in the same way that is 

 reported for farm crops has been a constant source of trouble 

 for it is quite natural to reason by analogy. Again it is little 

 wonder that the growers are discouraged to find some investiga- 

 tors arriving at the general conclusion that it does not pay to 

 fertilize the apple orchard and others by just as thorough investi- 

 gations arriving at the opposite conclusion. Yet both, from their 

 data, are warranted in their conclusions. 



From the various investigations and tests reported upon there 

 seems to be a general agreement that it will pay, and usually 

 quite well, to apply fertilizers to trees standing in sod. But 

 when the orchard is receiving a standard system of cultivation, 

 including a cover crop the results are not in harmony. It 

 appeals to the writer that one of the outstanding statements 

 pertaining to any fertilizer investigation in an apple orchard 

 should be, whether it is in sod or under cultivation, and the 

 orchard's history in this respect. 



It is doubtless a truism to say that the recommendations to 

 "feed the trees" have been largely based on the information 

 given us by the chemists. The chemical analysis of the tree and 

 its product is made and then the analysis of the soil on which the 

 tree grows is made. From this data is calculated the amount of 

 plant food which should be returned artificially to maintain the 

 fertility of the land. Obviously the trouble with such a theory is 

 that it does not take into consideration the mechanical or physical 

 condition of the soil or the important role of micro-organisms to 

 soil fertility and the associated factors — heat, moisture, and soil 

 sanitation. The physical theory and tOxic theory have both 

 shared in causing a new viewpoint to be taken of this important 

 study, both of which have been accepted in whole or in part by 

 many workers. These facts together with the results of the work 

 appearing in this bulletin lead the writer to make the general 



