1911.] PUBLIC DOCUMENT — No. 31. 341 



According to Ililgard ^ " Virgin soils with high })lant food 

 percentages are always prodnctive, jirovided, only, that extreme 

 physical characters do not interfere with normal plant growth." 

 By high 2)lant food percentages is meant 1 per cent, of acid 

 soluble potash, 1 of lime, the same or less of magnesia and .15 

 per cent, of jAosphoric acid. In case there is a low percentage 

 of one of the above elements, it is an indication that this will 

 be the first to fail, and will have to be supplied in the form of 

 farm-yard manures or chemical fertilizers. The total percent- 

 age of nitrogen in the soil is of less importance than the nitro- 

 gen percentage in the humus, of which there should be at least 

 •4 per cent, to insure satisfactory production. 



It will bo seen that none of the above soils could be classed 

 as highly productive, yet by comparing the analyses with the 

 standards for average soils as given further on, it will be seen 

 that, in so far as their chemical analysis is concerned, most of 

 them would be capable of producing satisfactory crops. 



Miscellaneous Soil Axalyses. 

 From time to time during the last ten or fifteen years the 

 station has had occasion to examine soils sent from different 

 sections of the State. The following tabulation shows the per- 

 centages of the more important fertilizer constituents which 

 they contained. The data concerning the history of each soil 

 are not at present available. From our present knowledge of 

 the value of chemical analysis in determining soil fertility it 

 is doubtful if such data would have proved particularly helpful, 

 so much depending upon the physical character of the soil and 

 subsoil, drainage and the character of the crops to be grown. 

 This matter is briefly referred to further on. In general it 

 may be said that the soils were taken from the cultivated fields 

 of Massachusetts farms. 



I Soils, by E. W. Hilgard, p. 343. 



