COMMERCIAL FERTILIZERS 
65 
the soil more acid, while nitrate of soda, carbonate oi 
potash and Thomas phosphate tend to make the soil alka- 
line. In the brands of fertilizers most used in this sec- 
tion, the acid-forming ingredients largely predominate. 
“One of the most important factors contributing to 
malnutrition is the exhaustion of the organic material in 
the soil. Fields where this disease occurs are found to 
contain only 1.65 per cent organic matter, while normally 
3 to 5 per cent should be present. 
“This deficiency is to be expected from such complete 
dependence on commercial fertilizers, which cannot take 
the place of stable manures and green manures in a per- 
manent system of agriculture. 
“Remedial and preventive measures recommended for 
malnutrition diseases are: (1) Limitation of the amounts 
of fertilizer used; (2) adjustment of the composition of 
the fertilizer to suit the crop requirements; (3) the ra- 
tional use of lime ; (4) the maintenance of the organic 
matter of the soil.” 
no. The use of lime. — The necessity of lime has been 
indicated in previous paragraphs. Malnutrition disease 
may become serious when lime is not used or when soils 
become acid. In vegetable gardening it is important to 
keep soils slightly alkaline and this is best accomplished 
by the rational use of lime. Va. Truck Expt. Sta. Bui. 
4, p. 80: “Experiments on Norfolk soils show that liming 
is very beneficial to all crops except peas, beans and 
tomatoes. On cabbage lime was added, just before 
planting, and the yield was greatly increased thereby.” 
There is great variation, however, in the need of vege- 
tables for lime, the watermelon, for example, thriving on 
distinctly acid soils. Further experimental work is needed. 
Lime not only neutralizes soil acidity, thus providing 
favorable conditions for friendly micro-organisms, but it 
also improves the physical character of soils, promotes 
decomposition, makes plant food available and enters into 
