414 MANAGING ORCHARD SOILS AND FERTILIZING TREES 



indicate that a legume sod, such as alfalfa or sweet clover, 

 would, under most conditions, be more satisfactory than a 

 mixture of grasses. The sod-mulch system would no doubt be 

 satisfactory in orchards planted on deep, fertile soils, and this 

 ^stem, or some modification of it, would be highly desirable 

 in orchards located on steep or very stony and rocky land, on 

 land which tended to be too damp because of seepage from 

 springs, and where there are other special factors. The ap- 

 plication of sufficient nitrogen fertilizers may make the sod- 

 mulch system very satisfactory. 



(4) Sod Mulch Plus Additional Mulch: Many orchards 

 are groT\Ti satisfactorily under a system of sod mulch plus addi- 

 tional mulch. In this system, in addition to the grass which is 

 cut twice a year and piled about the trees, other mulching 

 material such as straw, hay, or cornstalks is hauled in and piled 

 under the spread of the branches. About 50 pounds of air- 

 dried material per tree should be piled around trees ranging 

 from 1 to 4 years old. This amount should gradually be in- 

 creased to 100 or 125 pounds around a 10-year-old tree. In 

 older bearing orchards, from 200 to 300 pounds of such ma- 

 terial should be spread about each tree. The mulch should 

 not be placed close to the trunk, since injury from mice is 

 greater in such cases, but it should extend well out beyond 

 the spread of the limbs in order to cover the root system of 

 the tree. 



This system on good soils produces approximately the same 

 effects a§ clean cultivation plus cover crops. The loss of soil 

 moisture is apparently prevented just as well, and the heavy 

 mulch kills out the vegetation directly over the roots so that its 

 :growth does not injure the trees. 



Trees under such a system make excellent growth and are 

 ^quite productive. The fruit is often of better color than in 

 cultivated orchards, and the apples which drop are protected 

 and kept clean by falling on the mulch. 



Under many conditions a nitrate fertilizer should also be 

 ;added to the trees, and it will probably pay to fertilize the grass 



