190 POMOLOGY 



apples which had produced but one crop of fruit because 

 of its extremely low vitality, was fertilized in part about 

 the middle of April. ''The trees bloomed rather uniformly 

 over the entire orchard, but the blossoms were unusually 

 small and apparently lacking in vitality. However, after 

 the petals of the blossoms had fallen, the little apples on the 

 fertilized plots where nitrate of soda had been included 

 clung to the fruit spurs and began to grow in a perfectly 

 normal manner, while most of the embryo fruits on the ad- 

 joining unfertilized plots withered and dropped from the 

 tree just as the apples had been doing throughout the past 

 life of the orchard." At picking time of this first year one 

 row of eight trees which was fertiUzed with a 5-5 nitrate- 

 phosphate combination produced twenty-one barrels of fruit, 

 while the adjoining untreated row yielded nine barrels. 



The same effect of an early application of nitrate on the 

 set of blossoms is reported by Lewis. He finds that as a 

 result they secured a higher percentage of ''set," an imme- 

 diate change in character of foliage, and a stimulation of 

 wood growth. 



162. Phosphorus is rather low in many soils and in 

 animal manures, but is required in less amounts by fruit- 

 trees than either nitrogen or potassium (in the relation of 

 4N, 1 P2O5, 4K2O) as was seen above. However, the data 

 in regard to this element are rather unsatisfactory and in- 

 consistent in the orchard experiments. It would seem to 

 rank next to nitrogen in its requirement as an amendment 

 to the soil, although when applied alone the results are 

 frequently meager or negative. An exception is found in 

 certain sections where phosphoric acid has had a positive 

 result in encouraging the growth of clov^er in a sod orchard 

 (see Ohio experiments) which in turn is beneficial to the soil. 



163. Acid phosphate. — As a carrier of phosphoric acid, 

 this material seems to give the most satisfactory results 



