118 TOBACCO LEAF. 



not because the quantity of plant food it contains is 

 unknown, but because of the impossibility of determining 

 how much of it is available for the demands of the rap- 

 idly growing tobacco crop. If all the plant food is not 

 consumed the first year, especially the potash and lime, 

 it remains in the soil for the use of future crops. 

 Owing to the very slow action of manure, and the great 

 demands of tobacco, occasioned by the very rapid growth 

 of the plant, it is difficult to bring about a satisfactory 

 state of fertility from manure alone. And in the great 

 majority of instances, manure is no longer expected to 

 supply the entire amount of plant food, but is supple- 

 mented by the use of other materials. 



Effect of Manure on Soil. While manure is thus of 

 questionable dependence, alone, for tobacco food, it 

 possesses certain valuable qualities arising from the large 

 quantity of vegetable matter which it contains. This 

 vegetable matter is beneficial in many ways. It supplies 

 a stock of vegetable mold, or humus, that is often 

 lacking in the light soils on which tobacco is grown. 

 This humus absorbs moisture and heat, and retains the 

 nitrates set free in the soil. This valuable adjunct to 

 the proper state of fertility, is too often overlooked by 

 the advocates of exclusive chemical fertilizers. The 

 mechanical effect of manure is also of great consequence, 

 as it lightens very heavy soils by making them open, 

 porous and easy of cultivation, while it supplies moisture 

 and body to lands that are naturally of too light a 

 nature. 



Manure also promotes a quick fermentation that is 

 congenial to all plants, one of the results of which is the 

 conversion of nitrogen from a raw state to nitrates that 

 are suitable for plant consumption. On this account it 

 is used with benefit in conjunction with other nitrogen 

 supplies, especially as it also, in a measure, fixes and 

 retains this soluble nitrogen and thus prevents waste. 



