QUERIES AND ANSWERS. 133 



829. Q. After removing my cotton crop the fields became covered with Green 



a growth of green stuff, and I write to inquire if it would have any value Manuring, 

 as a green manure? 



A. I\Iost certainly. By all means plow under the weeds and grass. To 

 burn them is a most foolish practice. Plowed under before the seeds 

 ripen, no matter what kind of weed, they will to a small degree fertilize 

 the earth, and are valuable in loosening it so that air and moisture can 

 more readily penetrate it, and the roots of cultivated crops more freely 

 ramify. The continued application of commercial fertilizers will harden 

 and bake any land, consequently green manuring should be resorted 

 to whenever possible. 



830. Q. What is the average percentage of the vitality of farm seeds ? Seed vitality. 

 A. The government of Switzerland has established a Seed Control 



Station at Zurich, and during the year 1892 made nearly 6000 official 

 tests of vitality. The average was, of 



Red Clover 88 per cent. 



White Clover 77 



Alsike Clover 78 



Orchard Grass 81 



Fox Tail .63 



Blue Grass 55 



The Austrian Seed Control Station in 1892, paying special attention to 

 the subject of Sugar Beet seed, established an official standard of 80 per 

 cent, of germinating clumps as indicative of excellence. 



831. Q. Are all the vegetable oils of the same nature? Vegetable 

 A. No ; they nearly all differ, and are distinct in turn from the essential **'^** 



oils of the same plants, the essential oils being all volatile. Fixed fats 

 and oils are found in many agricultural seeds, notably in rape, or colza, 

 flax, hemp, cotton, castor beans and peanuts. All these contain from 

 10 to 50 per cent, of expressable oil. The essential oils are obtained by 

 boiling and distillation, and it is these oils which give the odor to plants. 



832. Q. My attention has been called to the condition of the leaves of Mining Flies. 

 my beets and radishes, all of which are channeled out or mined by some 



worm. How can I stop it? 



A. The injury is done by the larvae of some one of the mining flies. 

 There is no remedy to apply to the present crop. The only course is to 

 attempt to destroy the insects after they drop to the earth to remain all 

 Winter. This may be partially done by oil, salt, lime. 



833. Q. Have you a table giving the number of plants to the acre of Plants 

 those sorts of garden vegetables which are usually or sometimes started *** Acre. 

 under glass for transplantation into open ground ? 



A. The number of plants set to an acre depends on the distance be- 

 tween the rows and the spaces between the plants in rows, some market 



