ORCHARD SOILS 139 



not naturally well drained, aitificial drainage may be very 

 desirable if not necessaiy. While kinds and varieties of 

 fruit will vary in their susceptibility to "wet feet," yet prac- 

 tically all fruit-trees do poorly if the land is regularly soggy 

 or springy during any extended period of the growing season. 



When artificial drainage is resorted to, the depth of the 

 tiles and the distance apart the lines are placed will vary 

 with the nature of the soil and the amount of water which 

 must be drained. In a heavy soil the lines of tile are com- 

 monly placed at 2 to 23^2 feet deep, and about 2 rods apart, 

 while in a sandy or gravelly soil the depth would be greater — 

 from 3 to 33^ feet. That is, the more open the soil the greater 

 the distance the drainage water may be drawn. 



122. Organic matter. — Probably any system of perma- 

 nent agriculture should involve the returning to the soil of a 

 plant residue or vegetative matter. This seems fundamental 

 because investigation has entirely established the existence 

 of a large soil flora and the necessity of bacterial action for 

 the continuous availability of plant-food materials. A soil 

 veiy low in organic matter is usually of poor tilth and sup- 

 ports a stunted tree growth. Also the returning of vegeta- 

 tion, especially legumes, to the soil maintains a much better 

 supply of nitrates than when the soil receives "clean" til- 

 lage or is entirely untilled. Many orchard soils are mate- 

 rially improved in texture by plowing in a rank or heavy 

 growing crop. This may be replaced after a few years by 

 a nitrogenous crop. 



The student should appreciate, however, that it is often 

 a long and expensive process to reconstruct a soil devoid of 

 humus, or a heavy intractable clay into one which is well 

 adapted to orcharding. From an economic standpoint, it 

 is better to select soil that is already adapted to the crop 

 to be grown and then by reasonable amendments maintain 

 its fertility. 



