Drugs and Medicinal Products, 



498 



[DECEMBER 1900. 



Our method of applying water on the 

 beds is a cheaper and simpler method 

 than steaming the beds and far better 

 than the method of burning them, 

 adopted in some parts of America.* 



* In America it is the general custom to 

 burn the soil of the seed-beds by burning grass 

 and logs on top, previous to sowing. The ob- 

 ject seems to be to destroy the weed seeds, 

 which are mainly present in the upper two 

 inches of the soil, and which are killed off by 

 burning or heating the bed. Another advant- 

 age is that by burning, certain mineral-plant- 

 food, as for instance potash salts, is made more 

 available for use by the plant. But the import- 

 ant organic matter or humus is largely destroyed 

 by burning, which liberate the nitrogen, reduc- 

 ing the amount available for plant-food, and the 

 destruction of the humus largely reduces the 

 moisture-retaining capacity of the soil, which 

 is a most important drawback with our climatic 

 conditions in South Africa. Scarcity of wood 

 for burning has lead to the invention ot a tobacco- 

 bed burner, which is a movable device especially 

 designed for burning seed-beds. It is thought, 

 however, that for our South African conditions 

 burning is not advisable. 



Methods have also been devised to steam the 

 soil of seed-beds. Mr. Ingle, late Chief Chemist 

 of this Department devised and described such 

 a method in a previous number of this Journal. 

 Mr. A. D. Shamel of the United States Depart- 

 ment of Agriculture has also devised a method 

 which seems to be in practical and successful 

 use in Connecticut, and which is described as 

 follows:— "A steam-pan is made of sheet-iron 

 10 feet long, 6 feet wide and 6 inches deep. 

 Attachments are made which provide for the 

 introduction of steam into this pan for the 

 connection of the steam hose or pipe running 

 from the steam boiler to the pan. This steam 

 hose should be at least 1 inch in diameter and 

 50 feet long, so as to permit the supply of an 

 abundance of steam and in order that the box 

 may be moved without moving the steam boiler. 

 The soil of the seed-bed is fertilized and pre- 

 pared in the same manner as for the sowing of 

 the seed. The pan is turned over a section of 

 this prepared soil, and care is taken that the 

 edges of the pan sink into the loose soil, so as to 

 prevent the issue of steam from beneath the 

 edges ot the pan. The steam is now turned into 

 the pan, and being confined under the pan, 

 under pressure it rapidly heats the soil to the 

 desired depth. A strong pressure should be 

 maintained on the steam boiler and a full supply 

 turned into the pan. In the beginning the 

 temperature of the heated soil should be raised 

 to 175° F. to a depth of at least four inches, and 

 this temperature should be maintained for 

 about one hour. This treatment destroys weed, 

 seeds and disease-germs in the soil, and improves 

 the condition of seed-bed soil for the growth of 

 tobacco seedlings. About 600 square feet of the 

 bed surface can be treated in one day by this 

 plan. The tobacco seed should be sowed the 

 following day and lightly raked in." 



This method appears to be quite effective, 

 but it may prove too elaborate and too expensive 

 for our farmers 



Quality and Quantity of Seed.- One 

 ounce of tobacco seeds contains from 

 300,000 to 400,000 seeds, but owing to 

 the smallness of the seed and the fact 

 that a considerable percentage of it may 

 not be good, 30,000 to 40,000 is considered 

 a good average yield of seedlings from 

 one ounce of seed. Even on this basis 

 it is the custom of tobacco growers in 

 oversea countries to sow about three 

 times the amount that will actually be 

 required to plant on a given area. 



In the Transvaal most of the tobacco 

 planters do not measure the quantity of 

 seed to be used for a certain area and con- 

 sequently sow too thickly, which causes a 

 great deal of loss through disease and 

 even then produces only weak seedlings. 

 During our experments in our tobacco 

 stations we have found that to obtain 

 more good and healthy seedlings from 

 one ounce of seed, at least one hundred 

 square yards of beds are required. This 

 is partly due, first to our only sowing 

 well-matured and selected seed, of which 

 the quality is far better and the germi- 

 nation power much greater ; secondly, to 

 our beds being well prepared. It must 

 always be remembered that in order to 

 raise good, strong, and healthy seedlings 

 it is much better to soiv too little than too 

 much seed. 



Seed.— On account of the care and 

 expense that have been devoted making 

 and preparing the seed beds the import- 

 ance of using ouly well-bred, thorough- 

 ly cleaned seed which is tested for germi- 

 nation, will be evident. For the main 

 crop only seed should be used of plants 

 which are grown on the farm, and these 

 should be especially selected plants. 

 The seed should be selected from bagged 

 plants of the finest type, from the main 

 terminal flower-cluster, from the largest 

 and strongest capsules («eed pods) after 

 having taken off the smaller and weaker 

 ones, having only about sixty capsules 

 to the crown stalk, and finally the 

 heaviest seed must be separated and the 

 light seed be discarded. A. full descrip- 

 tion of how to select plants for seed 

 production will be found in Farmer s' 

 Bulletin, No. 28, which is issued to 

 tobacco planters free of cost on applica- 

 tion to the Government Printer. 



If newly introduced seed is to be used 

 it should only be done on a small scale ; 

 from these plants enough seed can be 

 saved of varieties or types which prove 

 successful and which produce a good 

 marketable leaf. 



Seed for the main crop should have 

 good vitality, a condition which can be 

 easily tested by placing one hundred 

 seeds between two moist blotters, keep- 

 ing them moist between two plates for 



