April, 1932] Agricultural Research in N. H. 17 



thoroughly incorporated in the surface 8 inches of soil. The orchard 

 was then seeded down in order to allow the roots of the trees to enter 

 the surface layer of soil in which the phosphorus had been incorpo- 

 rated. The amount of phosphorus used was sufficient to increase by 

 from 50 to 100 per cent, the total amount of phosphorus in the surface 

 8 inches of soil. To date records of yield only have been made in this 

 orchard. The crop of 1930 was heavy and the crops of 1929 and 1931 

 were light. It is of considerable interest to note that as a three- 

 year average 6 out of 7 pairs of plots receiving phosphorus show a 

 greater yield than the respective controls; the average for the whole 

 group shows an increase of 32 pounds of fruit per tree where the phos- 

 phorus is used. 



In the opinion of most authorities direct benefit to apple trees from 

 applications of phosphorus has not yet been demonstrated. Statistically 

 the increase of 32 pounds occurring in these plots is too small to form 

 a definite conclusion, yet the indications of benefit from the phosphorus 

 are of very considerable interest. The grass mulch has not been visibly 

 different in the phosphorus and the control plots. If growers are to 

 invest money in phosphorus and potash fertilizer there would seem to 

 be much greater hope for benefit if these materials are incorporated in 

 the soil rather than spread on the surface. 



Experiments were continued in three orchards as to the comparative 

 merits of a 5-8-7 complete fertilizer and a mixture of sulphate of 

 ammonia and nitrate of soda containing exactly the same amount of 

 elemental nitrogen per tree. The orchards selected are ones in which 

 for a period of years nitrogen only has been used as a fertilizer. If, 

 by this practice, a deficiency in phosphorus and potash is brought 

 about, such an orchard should be most favorable to determine the value 

 of correcting this deficiency by the application of complete fertilizer. 

 The application of complete fertilizer is carried to a sufficient distance 

 from each tree to insure that all of the area which the roots can pene- 

 trate is fertilized. The records include the amount of crop, color and 

 some other factors. Each tree receiving complete fertilizer is com- 

 pared to a control receiving nitrogen only, situated as close as prac- 

 ticable but in no instance close enough so that the roots of the control 

 tree can enter the area of the soil fertilized with complete fertilizer. 

 In an orchard of mature Baldwins complete fertilizer has shown on a 

 two-year average a rather significant decrease in yield. In one 

 Mcintosh orchard a small decrease in yield is experienced, and in the 

 other the yields are almost exactly the same under the two treatments. 

 Considering the fluctuations normally experienced in field tests it is 

 not believed that the decrease in yield is due to the fertilizer, although 

 it is possible that since the nitrogen in the complete fertilizer is not so 

 readily available the trees may have suffered slightly from this fact. 



Percentage of color, obtained by estimating the surface covered by a 

 characteristic red on a representative sample of apples from each tree, 

 seems to be in relation to the yield. If yields on plots receiving com- 

 plete fertilizer are lower the color is better. It is a recognized fact 

 that heavy bearing reduces both size of the individual fruits and color 

 of the crop. 



