40 



FUNDAMENTALS OF FRUIT PRODUCTION 



did not become dry for a week or two after the corn ground had become dry. 

 The great difference, as regards soil moisture between the clean cultivation 

 on the one hand and the rye and oats on the other is fully appreciated only when 

 it is remembered that the moisture in excess of 8 or 10 per cent, (in this particular 

 soil) is available to plants. . . , In 1902, the plots did not vary greatly as regards 



Apnl_ 



o0.5 



_May_ 



June 



1901 



Aug. Sept. 



Oct. 



Fig. 1. — Percentages of soil moisture in orchard plots and inches of rainfall during 

 summers of 1901 and 1902. The curved lines indicate the fluctuations in soil moisture 

 content. The vertical bars show dates and amounts of rainfall. (After Emerson.*^) 



soil moisture. Naturally, no method of culture dried the ground seriously at 

 any time during this very wet season, when over 28 inches of rain fell during the 

 4 months from May to August inclusive."^* 



Table 22 presents data showing the effects of the various intercrops 

 in this Nebraska experiment upon the drought killing of newly set trees. 



