lo Aug., 19 1 2.] 



The Olive. 



465 



Summary of Results of Crop Kotation in Adgell Field, 

 rothamsted. since 1 848. 



(2) On Section II. the application of phosphates has maintained the 

 yield of turnips, and has increased the wheat yield by 25 per cent., while 

 on the unfertilized plot the yield of turnips dropped to less than i ton 

 per acre, the plot manured with phosphates has averaged nearly 12 tons 

 per acre during the last twenty years. The barley crop shows a falling 

 off, but it remains twice the average of the unfertilized barley crop. 



(3) The turnip crop, on Section III., manured with phosphates and 

 nitrogen, has increased from 12 tons to 20 tons per acre. The barley 

 crop, which follows the turnips, seems to have suffered from the increased 

 demands made by the heavy crops of turnips. The average yield, how- 

 ever, is more than twice that of the unfertilized plot. Finally, the high 

 initial wheat yield, 30.3 bushels, has not only been maintained throughout 

 the whole sixty years, but has even increased during the last twenty years 

 to 36.4 bushels. Soil fertilization is, therefore, bound up with crop rota- 

 tion, and is indispensable for the maintenance of soil fertility. 



(J^o be continued.) 



THE OLIVE. 



By L. Macdonald, F.R.H.S., Horticulturist. Dookie Agricultural College. 

 {Continued from page 408.) 



Pests — continued. 



The Rrowii or Black Olive Scale {Lecatiium olece) : This pest is said 

 to be the most general among our olive trees. Owing to its adaptability 

 to various conditions and its disposition to attack such a large number ot 

 plants, it is found to be one of the worst to cope with. Citrus trees, many 

 of our garde.i shrubs, and even deciduous fruit trees, are liable to its 

 attack. Usually it is accompanied by another serious trouble, the Sooty 

 Mould Fungus. This pest appears to be the natural concomitant of the 

 olive scale living as it does on the .sugary .secretion of the scale insects. 



