REPORT OF THE CHEMIST. 



167 



No great differences between the varieties are here to be noticed, though the 

 Northern Spy presents some striking variations from the average. Its ash contains 

 nearly 3 per cent more phosphoric acid, nearly 1 per cent less soda, about -5 per cent 

 more oxide of iron and alumina, and about -5 per cent more silica than the ash of the 

 other apples. 



The ratio of the potash to the phosphoric acid in the ash of the fruit is 6 to 1 • in 

 the ash of the older leaves (see table), it is 2 to 1. Relatively, therefore the demands of the 

 leaf and the fruit on the soil for these two constituents are very different. It inio-ht here 

 be remarked that the greater quantity of the ash ingredients of the fruit is contained in 

 the seeds and walls of the ovary, comparatively little being found in the flesh of the 

 apple. 



A comparison of this table with that showing the composition of the ash of the 

 leaf, will reveal further interesting features. The total percentages of ash in similar 

 weights of leaf and fruit, are as 3*46 to -28. Lime is much more abundant in the ash 

 of the leaf, while magnesia, oxide of iron and silica are about the same, taking the 

 older leaves for comparison. 



For the purpose of a practical presentation of the subject, the data presented in 

 the following table have been prepared : 



Weight of Important Fertilizing Constituents withdrawn from the soil. 



Note. — In the above calculations the following data are used : Forty trees per 

 acre in an orchard 25 years old yield, on an average, one hundred and sixty (160) 

 barrels. One barrel contains 2 bushels and 3 pecks. 



We have here the number of pounds of nitrogen, phosphoric acid and potash esti- 

 mated as contained in one barrel of the fruit, and the amounts removed per acre by a 

 good crop. None of the quantities are at all excessive, and the cost of returning them 

 would not be great. The largest demand is on the potash in the soil ; next comes the 

 nitrogen, and lastly the phosphoric acid. In the case of the leaves, the nitrogen stood 

 first. 



For the vigorous development of the tree and an abundant crop of fruit, the soil 

 must contain these constituents in a more or less immediately available condition. It is 

 for this reason, as well as to replace the exhausted plant food, that fertilizers are neces- 

 sary to profitable apple growing. 



Nitrogen. — To supply nitrogen, some organic manure is perhaps the most econo- 

 mical. Barnyard manure or the turning under a leguminous crop (the latter being rich 

 in nitrogen) are to be recommended. Besides adding nitrogen, they furnish humus or 

 decaying vegetable matter, which serves a useful function by liberating carbonic acid 

 and which in turn sets free locked-up forms of mineral food. Humus, moreover, has 

 much to do in bringing about good tilth and in the retention of soil moisture. As the 

 period of growth and fruit development in the apple is comparatively long, organic 

 manures in most instances will probably give better returns than those containing 

 more soluble forms of nitrogen, such as nitrate of soda or sulphate of ammonia. 



