No. 7. 



DEPARTMENT OF AGRICULTURE. 



243 



The results in Table VI indicate that, even in trying seasons such 

 as the last two have been, the moisture in orchard soils may be con- 

 served at least as effectively by a good mulch as by tillage. This 

 conclusion is corroborated by moisture determinations made by 

 Shutt, of Ottawa, Canada, in 1905 and 1906.t He also has found 

 that leguminous plants, particularly those of dense and matted 

 growth like hairy vetch, are much less severe in their drain on soil 

 moisture than the grasses; and that the shade of the growing vetch 

 is a better conserver than the mulch formed by cutting and leaving 

 it in place. In other words, the loss by capillarity and surface 

 evaporation from the practically bare ground was greater, under 

 the conditions at Ottawa, than the transpiration through the 

 legume. J The cover on our mature orchard is grass only, while 

 on the young orchards a scattering growth of alsike or of medium 

 red clover has been maintained in addition. 



In further explanation of the difference in effectiveness of the 

 mulch and cover-crop methods in Tables VI and VII, we may call 

 attention to the hastening influence on bearing, which sod undoubt- 

 edly exerts under favorable conditions. This was shown in our 

 results of last year,§ where sod on these same three orchards sur- 

 passed clean tillage in yield by thirteen per cent. It is also shown 

 here later, especially in the sod-manure plot of Table IX. But the 

 fact that this sod influence can be easily overdone and made to dis- 

 appear under unfavorable conditions, is clearly shown in our re- 

 sults from the unfertilized sod plots of Table VI. 



The next table shows the effect of adding fertilizers to the four 

 cultural methods. All unfertilized plots are excluded from this 

 table, and the yields given include both the manured and commer- 

 cially fertilized plots under each method. 



TABLE VIII 



Influence of Cultural Methods on Yield, with Fertilization 



Expts. 217, 218, 219. Young Orchards 



Expt. 221, Mature Orchard 



1908 yields, 



1909 yields. 

 Totals, ... 

 Ratios, --- 



6,684 

 28,297 

 34,981 

 106.3 



10,351 



22,545 



32,896 



100 



tCentral Experiment Farm. Report of the Chemist, p. 151, 1906. 

 :ibid. 1904. p. 158. 

 §Pa. Bui., 91:15. 1909. 



