102 FERTILIZERS 



two having been treated in exactly the same way except in the 

 matter of fertilizers, it is difficult to avoid drawing the conclu- 

 sion that the fertilizer is responsible for the difference. In the 

 orchard fertilizer experiments at the Massachusetts Agricultural 

 Experiment Station (with which experiments the writer has had 

 no connection) the thing which most impresses any one who 

 studies the results and examines the trees, is the extremely poor 

 showing made by the trees which had no fertilizer. We may 

 disagree decidedly as to the relative merits of muriate and sul- 

 fate of potash, or as to whether bone meal is best as a source of 

 phosphoric acid, but none can escape the conclusion that under 

 the conditions of this experiment any fertilizer combination used 

 was greatly to he preferred to no fertilizer at all. 



Influence of Nitrogen. — With so much difference in opinion 

 as to what forms of fertilizer, if any, are required, it is hardly 

 to be expected that there should be very general agreement as to 

 the particular effect of the different fertilizer elements, yet all 

 are agreed that nitrogen, in any form, is likely to produce rapid 

 wood growth with large, dark green leaves and long terminal 

 shoots. If the application of nitrogen is carried to excess, the 

 wood growth may be made at the expense of fruit, though up to 

 a certain point nitrogen increases the yield. It almost always 

 decreases color, principally because the fruit, like the leaves, is 

 large in size and does not reach sufficient maturity to begin to 

 color until late in the season. The heavy foliage also reduces the 

 color by shutting off the sunlight. In recent experimental work 

 in orchards, however, nitrogen has been the element that has most 

 frequently shown results in increased yields. 



Influence of Potash. — It is known that potash enters into 

 the fruit acids and is a very large part (more than 50 per cent.) 

 of the ash of fruits. Potash has also been credited, and perhaps 

 rightly so, with increasing the color in fruits, but this effect is 

 probably produced by the influence which potash has on the 

 general growth of the tree and does not come as a direct influence ; 

 that is, potash will not change tlie green color of apples to a red 

 color as nitrogen will often change the yellow color of leaves to a 

 green color. On the other hand, it is well known that potash is 

 important in getting a good growth of leguminous crops, particu- 

 larly clovers, and it may often be desirable to use it in connection 

 with cover crops, applying it when they are sown. 



