No. 6. DEPARTMENT OF AGRICULTURE. 443 



Phosphates, when used in combination with nitrogen or in a com- 

 plete fertilizer, maintain their position as the next limiter after 

 nitrogen, though they are closely pressed by potash in Table VI. 

 On the other hand, neither acid phosphates nor ''floats" nor lime, 

 when used alone, have shown any consistent benefits on yield thus 

 far. Their apparently negative influences on yield may be smoothed 

 out in time, as indicated by some of the results of the past year. 

 There is some evidence, however, that certain of these negatives 

 really indicate a toxic action that is manifested only under certain 

 conditions, but we have not yet carried this far enough for definite 

 statements. 



The important advantage shown by manure, especially in Table 

 VI, is doubtless largely due to the very full crops on the manure 

 plots of those experiments during the })ast year, which was rather 

 of an off year for the similar plots receiving complete fertilizer. 

 The better moisture-consei'vation under the manure and the larger 

 amounts of plant food carried in it also probably account for a part 

 of the superiority. In general, however, we do not find any important 

 superiority in manure over a proper commercial fertilizer, neither 

 in actual or net increases. Manure is undoubtedly a safe and valu- 

 able material to apply in orchards, when it can be satisfactorily 

 obtained in suf^cient amounts. But with very few exceptions, thus 

 far in our experiments as a whole, wherever manure has given im- 

 portant increases, these increases have been approached or surpassed 

 by a proper commercial fertilizer. 



CORRELATION BETWEEN YIELD AND GROWTH 



In regard to growth, it will be observed that, in general, the im- 

 provements in it have accompanied those in yield. The same materials 

 that have improved the one have generally improved the other. In 

 other words, as a rule, our best growing plots have been our best 

 fruiting plots. Contrary to a prevalent notion, therefore, we may 

 say that growth and fruiting are not necessarily antagonistic, but 

 rather are associated, unless either should occur in abnormal 

 amount. 



DATA AND DEDUCTIONS ON COLOR 



In regard to color, it will be observed in Tables V and VI, that 

 none of the applications have given any important increases, and 

 most of them have giveji decreases. Similar results have also been 

 uniformly obtained elsewhere, so far as we have received the reports. 

 The same is essentially true of applications of iron salts. From 

 these and other considerations, therefore, we believe that color in 

 apples can not be materially improved by soil applications, and 

 that it is primarilij dependent on maturity and sunlight. 



This refers only to the red colors in apples. The yellow colors 

 can probably not be affected by any external agency. Physiologic- 

 ally, the yellow color is connected with certain bodies located in the 

 superficial layers of cells in the apple skin. It develops independent 

 of light, and its intensity depends merely upon the degree of ma- 

 turity or ripeness. The red color, on the otiier hand, is a constiuent 

 of the cell sap; it is capable of being influenced by a number of 



