78 AGRICULTURE OF MAINE. 



nitrogen and potash, in order to test further their relative 

 values as carriers of phosphorus for trees. Basic slag was in- 

 troduced into this comparison in 1912. 



9. Lime also has failed in most cases, though it miy have 

 some value in aiding growth. In addition, it may have some 

 mdirect value in facilitating the growth of leguminous inter- 

 crops, and also in correcting a possible toxic action possessed 

 by the basic radicals of a number of salts, some of which are 

 present in commercial nutrients. 



10. At present the high-grade sulphate in our experiments 

 is showing no superiority over the muriate as a carrier of pot- 

 ash, but the reverse is usually true. The lower cost and easier 

 handling of the latter, therefore, give it the preference. It is 

 possible that the low-grade sulphate, or the 24 per cent, 

 "double-manure salt," as it is often called commercially, may 

 be superior on account of its magnesia content, but this has not 

 yet been fully demonstrated. 



11. The influence of proper fertilization is not transient. 

 The gains from it have been greater in the sixth and last year 

 of some of our experiments than in any earlier year. In one 

 case, these gains have exceeded 1,100 bushels per acre. Where 

 the crops of the full years are not too high, the yields usually 

 have been greatly steadied by proper fertilization. 



- 12. In all our experiments, the action of manure has proved 

 to be practically identical with that of a commercial fertilizer 

 rich in nitrogen and phosphorus. Their successes and failures 

 have coincided with but two exceptions, and in those cases 

 moisture rather than plant food was apparently the controlling 

 factor. The commercial nitrates and blood have acted more 

 quickly than the manure, and the potash in the latter has appar- 

 ently been less efifective than that in the commercial forms. 



13. In general, the influences that have materially increased 

 the yields have also increased the growth. This is true gen- 

 erally, unless either occurs to an abnormal extent. The phos- 

 phates seem to be a partial exception to this rule, and mild 

 injuries also may stimulate yield at the expense of growth. 



14. Manure and potash are the only fertilizing materials 

 that have shown 'a consistent benefit on the average size of the 

 fruit. This is doubtless associated with their favorable rela- 



