DRAINAGE AND IRRIGATION. 45 



A properly made drain leaves in moorlands enough 

 moisture in their smaller pores for furnishing to the 

 roots of young trees the necessary plant-food, helping at 

 the same time to impact the roots in the soil ; while the 

 air in the emptied large pores continues circulating, and 

 neutralizes the acids produced by the moisture when com- 

 ing in contact with the organic matter of the soil. 



It is, therefore, obvious that in regulating the aqueous 

 conditions of a tract of land, both the efflux and the in- 

 flux of the water must be arranged so as to avoid the in- 

 jurious effects of being too wet, and yet to retain in the 

 ground the moisture necessary to plant vegetation. 



In regulating the conditions of the water with swampy, 

 boggy and peaty soils, an attempt should be made to 

 bring fresh soil over the surface. This is done by dig- 

 ging parallel ditches of the proper distance, depth and 

 width, and throwing the dug-out soil at both sides upon 

 the thus formed beds. This culture, called border or 

 bed culture (Eahatten KuUur), serves not only to im- 

 prove the chemical but also the mechanical condition of 

 the soil, and therefore has the same result as deep 

 plowing'has upon common soil. 



The boggy or peaty soils especially require chemical 

 improvement, as they mostly need the important sub- 

 stances for the growth of trees — the mineral components. 

 For this reason they are unable to make their richness of 

 nitrogen available to the trees, these being unable to appro- 

 priate the nitrogen, except after it has been converted, 

 with the help of some minerals, into nitric acid. Be- 

 sides, the spongy condition of this kind of soil does not 

 furnish to the roots of trees the rest and stability neces- 

 sary for the development of the root system, because the 

 soil, in receiving humidity, swells up, and in drying up, 

 contracts; thus always disturbing the position of the 

 roots and preventing their development. 



The improvement of peaty tracts can best be effected 



