MASS. EXPERIMENT STATION BULLETIN 328 



192<? 21 22 '23 '24 '25 '26 27 '28 '29 '30 '31 '32 '33 '34 



Figure 1. Average Annual Shoot Growth, Mcintosh. 

 M — mulched plot C — cultivated plot 



Trunk diameter measurements have been taken each year except 1934. The 

 averages for each plot are shown in Table 3. 



The Mcintosh trees have grown most, followed by the Wealthy on seedling 

 stocks and Wealthy on Doucin stocks. The initial differences in 1921 before 

 differential treatments were begun are important. In each case the trees on 

 the mulched plot were larger than those on the cultivated plot, and the same 

 is true at the last measurement. Both varieties have made more trunk growth 

 on the mulched plots. The rather small differences here shown signify consider- 

 able differences in the size of the crown and therefore the bearing area, as shown 

 later. 



There is a close correlation between trunk growth and crop; in years of 

 heavy crop, trunk growth is small. This is clearly shown in the Wealthy trees. 

 The annual trunk increase in millimeters is as follows: 6, 13, 8, 9, 6, 12, 7, 13, 

 5, 13, 2, 15. The smaller figures represent growth in the crop years. 



The most significant figures in this table from the point of view of this 

 comparison are the percentage differences bptween the mulched and cultivated 

 trees. The differences are comparatively small in the case of Wealthy, but 

 there is a steadily increasing difference in the case of Mcintosh until after the 

 nitrate of soda was applied to the cultivated trees when there was a slight decrease 

 as would be expected. The differences between the mulched and cultivated 

 Mcintosh trees are probably due in part to more favorable natural conditions on 

 the mulched plot, but one cannot escape the conclusion that mulching has 

 favored growth. Had the cultivated plots been fertilized during the entire 



