A STUDY OF FACTORS INFLUENCING THE YIELD OF POTATOES 1179 



are more subject to leaching, probably a charge of 50 per cent to the first 

 crop would be more nearly correct. A uniform basis of evaluation has 

 been applied in this study. 



Home-mixed fertilizers 



Potato growers have never adopted the practice of mixing their own 

 fertilizer, even in the regions where potatoes are raised on a very extensive 

 scale. The advantage of using home-mixed fertilizers has usually been con- 

 sidered, to lie in a saving in cost rather than in an increase in yield. Woods 

 and Bartlett (1909) compared several home-mixed fertilizers with a 

 common ready-mixed commercial fertilizer of the same analysis. They 

 found only a very slight advantage, on the average, in favor of the home- 

 mixed fertilizers. 



In table 21 is shown the relative extent to which home mixing is practiced 

 in the regions surveyed. These figures indicate that an average of about 



TABLE 21. PER CENT OF GROWERS USING HOME-MIXED FERTILIZER ON POTATOES 



5.5 per cent of the potato growers in New York mix their own fertilizer 

 for potatoes. A comparison of the various ingredients which constitute 

 the home-mixed fertilizers used in these four regions is given in table 22: 



TABLE 22. PER CENT OF GROWERS USING VARIOUS INGREDIENTS IN HOME-MIXED 



FERTILIZERS 



