REPORT OF THE EORTICUTVRIST 31 



SESSIONAL PAPER No. 16 



table matter to plough under in the spring for the purpose of obtaining humus, and, 

 in the case of leguminous plants, nitrogen. In the autumn they act as catch crops, 

 preventing plant food from leaching. Experiments have been conducted to determine 

 the yields from the various cover crops, and, analyses have been made of the same. 

 The former have been reported on by the Horticulturist, and the latter by the Chemist. 



Mulching the Soil rvith Green Clover.— From 1898 to 1902 the system of cover 

 crops was changed in part of the orchard. Seed for the cover crop was sown in May 

 and the clover was allowed to grow during that season and to remain and protect the 

 ground the following winter. The second season, instead of ploughing under the 

 clover in the spring, it was allowed to grow and was cut at intervals during the summer 

 and was not ploughed up until the next spring. By cutting the clover when the flower 

 heads were just beginning to show, when it was from 18 to 20 inches in height, it was 

 found that from four to five good cuttings could be made, and by weighing some of 

 the material at each cutting it was found that about 25 tons of green clover was cut 

 during the season. The clover from each cutting was left to rot on the soil and acted 

 as a partial mulch. The trees did well under this treatment, but this system had to be 

 discontinued for a time on account of the increase of couch grass in the land. Wlien 

 an orchard soil is wet or so moist that drought is not feared this method will give good 

 satisfaction, but we do not advise it for most situations, as conservation of moisture 

 is usually a most important consideration, and this^san be brought about best by 

 thorough cultivation. 



Conclusions Reached Regarding Cover Crops. — Cover crops nrc valuable for pro- 

 tecting the roots of trees in winter, folding the snow, adding humus and plant food 

 to the soil when ploughed under, and acting as a catch crop in autumn to prevent 

 leaching of available plant food. In western Ontario, soil should be kept thoroughly 

 cultivated from early in the spring until about the middle of July. In eastern On- 

 tario and the province of Quebec cultivation may cease as early as July 1, as thorough 

 ripening of the wood is more important than conservation of moisture. The cover 

 crop should be turned under in the spring and cultivation begun as early as possible. 



Top Grafting Apples. — It has been known for many years that trees having poor 

 trunks are much more satisfactory when top grafted on hardy trunks and will bear 

 sooner, and it was generally supposed that trees top grafted on hardy stocl^s would be 

 decidedly hardier in the wood than when grown in the ordinary way. As none of the 

 best winter apples had been found hardy enough at Ottawa when grown as standard 

 trees it was decided to try top grafting. From 1898 to 1903 ninety varieties of apples 

 were top grafted. After top grafting, some of the varieties which had been too tender 

 gave promise of succeeding, but the severe winter of 190-3-4 killed practically all those 

 which had proven tender when tried as standard trees. A Northern Spy which had 

 been top grafted on Duchess for thirteen years was killed completely back to the stock 

 which was as healthy as ever. From this experience with top grafting tender varieties 

 on hardy stocks it seems conclusive that top grafting will not make a variety suffi- 

 ciently hardy to withstand the winter wiere the climate is similar to that at Ottawa, 

 if it is tender when grown as a standard. Top grafting will, however, bring a tree 

 into bearing sooner and will permit of growing varieties which sun-scald on the trunk 

 or are weak in the trunk in other respects. 



Sun-scald. — There is much injury to apple trees from sun-scald in the northern and 

 eastern parts of Ontario and the province of Quebec, and many a grower has been 

 discouraged on account of the injurj' to his trees by it, trees frequei^tly being killed 

 outright by it. Newly planted trees are, as a rule, more seriously affected by it than 

 older ones, but both often suffer badly. The unhealthy appearance of the bark on 

 the south and southw.est sides of the trunk of the tree and on the larger branches is 

 the first indication of this injury. Afterwards the bark dries up and falls away. 

 The injury occurs during the latter part of winter or very early in the spring when 

 there are warm days and cold nights. It has been found at the Experimental Farm 



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