40 STATE POMOLOGICAL SOCIETY, 



No one would think of growing potatoes or corn twenty 

 years in succession without fertilizer. Is it any wonder that old 

 orchards do not yield well? 



In no branch of agriculture is there a better chance to avoid 

 paying i8c. a pound for nitrogen than by allowing bacteria to 

 trap nitrogen from the air and store it up in the roots of plants 

 grown as cover crops. For years the orchard at the University 

 had the following treatment. The land between the trees was 

 plowed early in the spring and frequently harrowed until about 

 July 15th. Crimson clover, winter vetch, or rye was grown 

 and allowed to occupy the land until the following spring when 

 the same thing was repeated. The clovers and the vetch both 

 belong to the family of plants in the roots of which certain 

 bacteria store up nitrogen taken from the air. In our case 

 the vetch proved the hardier and better of the two crops. 



An ordinary crop of crimson clover in the green state (8 tons 

 to the acre) will carry to the soil — 

 68 lbs. Nitrogen 

 20 lbs. Phosphoric acid 

 78 lbs. Potash 

 Worth in all about $17.00. 

 \'etch v.ill return (8 tons to the acre green) 

 102 lbs. Nitrogen 

 23 lbs. Phosphoric acid 

 64 lbs. Potash 

 Worth about $22.00. 

 Red Clover returns (8 tons to the acre green) 

 68 lbs. Nitrogen 

 22 lbs. Phosphoric acid 

 78 lbs. Potash 

 Worth about $16.00 as a fertilizer. 



Every other year or once in three years rye was used in place 

 of the vetch in order that the soil should not become too rich in 

 nitrogen, causing too much soft wood growth in the tree. By 

 carefully watching the trees, how often the nitrogen gatherers 

 should be sown can be determined. The potash and phosphoric 

 acid costing much less than the nitrogen can be supplied in 

 chemical form. More than the supplying of the nitrogen or 

 the conserving of plant food and water which otherwise might 



