550 Report of the Department of Horticulture of the 



was supplied to the tilled trees during the whole period by plowing 

 under clover cover-crops. It was reasonable to assume that the 

 sodded trees were suffering from a lack of nitrogen in the last half 

 of the experimental decade. Therefore, Plats 5 and 6 in the sodded 

 half of the orchard, containing 52 of the 120 trees in sod, were given 

 annual applications, five in all, of nitrate of soda at the rate of 350 

 pounds per acre, a heavy dose. In some respects the results 

 were most surprising. The foliage was abundant and of a dark, 

 rich green, nearly as luxuriant as that of the tilled trees. There 

 were, therefore, high hopes of abundant harvests. Table VI, how- 

 ever, shows that, while the trees which were thus fertilized yielded 

 more than those not so treated in sod, they bore on an average 

 but a trifle more than half as much as those under tillage, the figures 

 being 3.17 barrels per tree for those in sod which had nitrogen; 

 2.28 barrels for sodded trees without the nitrate and 5.03 barrels 

 per tree for the trees cultivated ten years. A little calculation 

 shows that the nitrate of soda paid well for itself. 



The question will be asked, why was not the nitrate of soda tried 

 on the tilled land? The answer is, that at all times the tilled trees 

 seemed to be having too much nitrogen judging from leaf and wood 

 growth and the size and color of the fruit. The clover cover-crops 

 supplied more than the trees seemed to need. 



Influence on sodded trees of adjacent ground under tillage. — Plats 

 7 and 8 show very considerably larger yields than Plats 3 and 4 

 though all had the same treatment. So, too, the diameters of the 

 trees are greater in Plats 7 and 8. Why? Unquestionably, because 

 the roots of the trees in the outside rows in Plats 7 and 8 found their 

 way into adjacent ground under tillage though separated from the 

 cultivated land by a strip of sod 20 feet wide. They have, too, far 

 greater light area. Even the halves of the trees on the outside were 

 superior to the halves on the inside, in yield of fruit and luxuriance 

 of foliage. Account should be taken of this fact in considering 

 the results, for the evil effects of the grass in the sodded plats have 

 been diminished not a little by the escape of some of the roots of 

 sodded trees from the sod to the tilled land which surrounds the 

 orchard. Plates LI and L1I, reproduced from Bulletin No. 314, show 

 how roots from the sod pass into tilled land though none were 

 passing the other way. 



