58S STATE BOARD OF AGRICULTURE. 



providing better couditions for its decomposition iu the soil. As the 

 humns of the soil is reduced by successive cultivations and cropping, the 

 nitrogen content of the soil, its water-holding capacity, and crop pro- 

 duction are likewise decreased. This emphasizes the necessity of an- 

 nually replacing the organic matter lost through decomposition to 

 maintain soil fertility. While cover-cropping is the most economical 

 means of annualh^ furnishing this organic matter, many growers are 

 not producing enough humus with their cover-crops to replace it as 

 fast as it decomposes; hence their orchard soils become less productive 

 eacli year. Humus is also very essential because it improves the physi- 

 cal condition of the soil; it makes a loose, sandy soil more compact, 

 while it loosens up a hard clay soil making it more friable and mellow. 



The beneficial effects of a cover crop on growth and fruit production 

 is, therefore, largely dependent upon the amount of humus and nitrogen 

 in the crop returned to the soil; in other words, the greatest effect may 

 be expected with the crop that consistently furnishes the greatest 

 amount of vegetable matter each year. It has been found that while a 

 crop like soy beans may be richer in nitrogen and also may add aerial 

 nitrogen to the soil, yet some other non-leguminous crop may improve 

 the soil couditions more, affecting growth and fruit production because 

 of its greater bulk of organic matter. 



The degree of benefit derived from the use of cover crops is also de- 

 pendent upon the time the crops are sown, the time when they are 

 turned under, and the adaptation of the crop to the soil and orchard 

 conditions. 



The necessity of an abundant supply of soil moisture and nitrogen, 

 as soon as growth begins, to insure a good setting of fruit and to stimu- 

 late early spur-growth, is not alwaj'S well appreciated by the growers. 

 Too many defer the turning under of the cover Crops until late spring. 

 Under these conditions the plant food in the cover crop does not be- 

 come available to the trees soon enough to be most beneficial, especially 

 on the crop of that season. T]ie maintenance, of the fruits upon the 

 fruit spurs to prevent an excessive "June drop" is largely dependent 

 upon an am])le supply of moisture and plant food. Tlie production of 

 vigorous fruit spurs for the production of fruit buds for the crop tlie 

 folloAving year infers an early cessation of gro>\th to permit a proper 

 storage of food in the bud and s])ur. Early ])lowing or disking-in of 

 the cover crop as soon as growth begins is very desirable; also the 

 seeding of the crop earlier in the summer than is frequently ])racticed, 

 early July being preferable to early August unless soil moisture proves 

 a limiting factor in seasons when the trees are producing a heavy crop. 



Cover cropping has many otlier desirable functions. The cover crop 

 absorbs the ]»lant food that becomes available in the soil' in late sum- 

 mer and fall that might otherwise leach away, returning it to the soil 

 at a season wlien the trees can most readily use it. It is of value in 

 catching leaves that di'O]) in the fall and that otherwise might blow 

 away. The value in this respect is emphasized by the following table: 



