No. 6. DEPARTMENT OF AGRICULTURE. 475 



stitutcd by an application of equal value of unleached wood ashes. 

 One ton of the latter being about equal in value to five tons of the 

 former. 



2. By the use of manufactured fertilizers. Just what the neces- 

 sary ingredients should be without knowing what elements are 

 lacking in the soil, is a very difficult question to determine, but the 

 substances most commonly deficient are nitrogen, potash and phos- 

 phoric acid. A mixture containing from 1^ to 2 per cent, of nitro- 

 gen; 7 to 9 per cent, of available phosphoric acid and 10 to 12 pei' 

 cent, of potash, will give excellent results wiien applied to orchard 

 land in quantities ranging from 400 to GOO pounds. 



3. By the growth of nitrogen-gathering crops in the orchard and 

 the application of a small amount of fertilizing materials consisting 

 mainly of potash and phosphoric acid. This seems to be the cheap- 

 est way of maintaining the fertility of an apple orchard, as it returns 

 to the soil more plant food than it takes from it, thereby perma- 

 nently appropriating its surplus fertilizing constituents to supply 

 the deficiency caused by the growth of a fruit crop. Sow the or- 

 chard to some corn crop immediately after the last cultivation, 

 using clover, if nitrogen is needed, and rye, buckw^heat or any other 

 plant that will furnish a winter cover where a non-leguminous 

 crop is wanted. This cover crop will catch the soluble nitrates; 

 subtract the available plant food from the trees; open the soil; give 

 it fibre and increase its moisture-holding capacity. 



It should be stated that the addition of humus to apple lands must 

 be practiced judiciously, as it can easily be over-done, if the nitrogen 

 fs not properly balanced by other fertilizers. The effect of crimson 

 clover and cultivation is shown by a very large, deep green, late 

 hanging foliage, and a strong, annual w^ood growth. The effect of 

 the injudicious use of the clover will be apparent in the fruit, before 

 it shows any injurious effect on the trees. It may keep the apples 

 growing so late in the fall that the red varieties do not develop 

 their color pigments before it is time to harvest them, and a yellow- 

 ish color predominates. The light colored fruit is probably due to 

 the addition of too much humus to the soil, to the moisture always 

 present, to a lack of potash, and especially of phosphoric acid, which 

 has as one of its distinct functions the maturing of fruits and wood. 

 It is also aggravated by the greater shade made by the dense mass 

 of foliage. 



TREES NEED "WATER. 



If the supply of water in the soil in an orchard is deficient when 

 the fruit is maturing, as it frequently is, the tree cannot produce 

 a full crop of apples, however well they may have been fed and 

 otherwise cared for. The lack of a suflScient amount of water in 



