6 



suits. The residual effect of fertilizer has so modified the soil 

 constituents that it is now practically impossible to grow cer- 

 tain crops where they formerly thrived. It is often seen that 

 large quantities may be used under one system of cultivation 

 with good results, while under another the result might be 

 injurious. Two crops might require a fertilizer of the same 

 quantitative analysis, but quite different in the ingredients from 

 which the materials are obtained. For instance, tobacco pre- 

 fers the potash from sulphate of potash, while on certain soils 

 peanuts yield better if treated with muriate of potash. 



There is still much room for the study of lime for use in 

 connection with truck crops. We know in a general way 

 what the results of lime are, but the application and interpre- 

 tation of these results in specific cases is sometimes quite 

 difficult. The Rhode Island Experiment Station has added 

 very greatly to our knowledge of the use of lime with many 

 of our truck crops, but the results obtained on the Rhode 

 Island soils do not necessarily apply in all particulars to other 

 types of soils. Under some conditions pulverized limestone 

 may give excellent results; under others the results from it 

 are negative; but those from freshly burned lime are quite 

 marked. The kind and quantity of lime that may be used 

 in connection with commercial fertilizer and stable manure 

 also vary with the character of the soil. The soils of the 

 Norfolk sandy loam type in the southern Atlantic States are 

 prone to acidity in reaction. Consequently larger quantities 

 of lime may be beneficially used on them in growing such crops 

 as potatoes, strawberries and beets, but. on soils which are 

 alkaline in reaction the results are often injurious. The in- 

 fluence of fertilizer on the acidity of the soil is still open for 

 investigation. Some investigators claim that it is practically 

 impossible to increase the acidity by the use of commercial 

 fertilizer. . However, experiments conducted at the Virginia 

 Truck Experiment Station seem to indicate that the acidity 

 may be markedly increased by the use of certain fertilizer 

 combinations. 



