REPORT OX THE KLAMATH MARSH EXPERIMENT. 9 



-pect the Lower Klamath Marsh differs markedly from the tnle lands 

 of the delta of the Sacramento and San Joaquin Kivers, which are 

 either neutral oi- slijrhtly acid; particularly in the lower depths. 



COMPAmSON WITH OTHER TULE LANDS. 



OA^ing to the rank ^Towth of the tule on the Lower Klamath 

 :Marsh it has been assumed that these lands have the same potential 

 value as the tule lands in the delta of the San Joaquin and Sacra- 

 mento Kivers. There are two fundamental differences, however, 

 between these two tracts: 



(1) The lands of Lower Klamath Marsh are formed almost entirely 

 from organic matter and the siliceous remains of diatoms. Draining 

 the tract and exposing this soil to the air will result in the rapid 

 oxidation and disappearance of the organic matter, accompanied by 

 a marked lowering of the surface. The residual material will 

 eventually be largely siliceous and will contain little plant food. The 

 delta tule lands, on the other hand, contain a large proportion of silt 

 deposited bv floods and do not undergo any marked changes as the 

 result of drainage, while the silt provides the necessary mineral plant 

 food. 



(2) The delta tule lands are either neutral or slightly acid in their 

 reaction, particularly iix the lower depths, while the lands of Lower 

 Klamath Marsh are markedly alkaline. This condition is due to the 

 presence in the latter case of black alkali (sodium carbonate), the 

 most injurious of the alkali salts. This salt combines chemically 

 with the disintegrated organic matter, which is one of the reasons 

 Avhv it is so difficult to remove bv leaching. A second reason is that 

 the compounds thus formed are colloidal in character and greatly 

 retard the movement of water through the soil, behaving in this 

 respect like particles of colloidal clay. 



Black alkali is least harmful under the conditions found in the 

 undrained marshland: that is. in the presence of submerged organic 

 matter. A part of the alkali combines directly with the organic 

 matter, and the remainder is largely converted into sodium bicar- 

 bonate, which is much less harmful to plant growth. It is under 

 such aquatic conditions that the tule makes its gi'owth in the Lower 

 Klamath Marsh, but as soon as the land is drained these favorable 

 conditions are gone. The sodium bicarbonate is converted into the 

 harmful carbonate, and as the organic matter oxidizes, all the alkali 

 with which it was combined is set free. Thus conditions grow 

 steadily worse in the zone into which the plant roots should penetrate, 

 while in the drainage zone below the soil remains as impervious as 

 before. 



[Cir. 86] 



