state; POM.OLOGICAL SOCIETY. 6l 



tial to their life, and if we should follow the problem to its ulti- 

 mate analysis the most desirable system of land management is 

 that which provides the most desirable conditions for the multipli- 

 cation of soil bacteria. I wish to state several propositions that 

 bear upon our orchard work, regretting that there is not more 

 time to discuss them. First, in cultivated soils the number of 

 bacteria is larger in well cultivated soils than in uncultivated 

 soils ; second, the number of bacteria increases with the amount 

 of organic matter or humus in the soil, and, third, an increase in 

 the number of bacteria means an increase in the available supply 

 of plant food. 



We have said that the cover crop increases the water holding 

 capacity of the soil. It makes it sponge like. The statement is 

 probably conservative when I state that fruit crops suffer oftener 

 from dry weather than from lack of plant food. There is prob- 

 ably not a fruit grower in the room whose apples or other fruit 

 crops have not been reduced in volume by dry weather. Yet if the 

 soil had been prepared to hold a large amount of water, and if 

 the winter rains and snow had been conserved by judicious til- 

 lage, it is probable that, in nine years out of ten, a fruit crop could 

 be kept in a vigorous growing condition in the droughtiest times. 

 It has been well said by Bailey that the people in the dryest sec- 

 tions of the country suffer least from drought. They catch all 

 the water they can, and then hold it in the soil. 



To illustrate the effect of turning under three cover crops on 

 the water retaining capacity of a soil in a dry spell the following 

 figures are taken from moisture analyses made by Cornell 

 University : 



Soil in which three crops clover had been turned under had 

 15% of moisture in July. An adjoining soil with no crops turned 

 under had 8.75%, and lastly, the cover crop, especially if a legu- 

 minous one, furnishes nitrogen to the soil, through the bacteria 

 that live on the roots of the plants. The time will not allow us 

 to discuss this phase of the question further than to say that 

 every pound of nitrogen used in the ordinary fruit growing oper- 

 ations can be supplied free of charge by leguminous crops, turned 

 under, in the form of cover crops. 



There are two general kinds of orchard cover crops, first, 

 leguminous crops or those that can make use of the free atmos- 

 pheric nitrogen through the bacteria on the roots of the plants. 



