290 SOIL PHYSICS AND MANAGEMENT 



Flooding was begun on March 1, 1903, and in November, 1903, 

 alfalfa was seeded on three acres, which was cut six times the next 

 year, producing a total of 25,000 pounds of alfalfa hay. 



Other tracts, North Yakima, Washington, Billings, Montana, 

 and Tempe, Arizona, were reclaimed. The cost of installing the 

 drainage system varied from $21 to $35 per acre. 



Hardpan. Where hardpan occurs in the subsoil reclamation is 

 a much more difficult process. This layer usually varies in depth 

 from one to four feet or even more. The cementing material may 

 be calcium carbonate, iron compounds or other substances and may 

 be from a few inches to several feet in thickness. In some instances 

 the action of the water is to disintegrate the hardpan, and where 

 this occurs little difficulty is caused by it. Calcium carbonate some- 

 times acts in this way. Usually this does not occur and it becomes 

 practically impossible to leach out the alkali because the hardpan 

 will not permit the water to pass downward. The alkali may be 

 leached to the depth of the hardpan, but much of it remains in this 

 stratum and soon rises. If the hardpan is due to black alkali it is 

 necessary to neutralize this with gypsum before flooding. 



Most soils, especially silt loams, clay loams, and clays, are 

 injured more or less by flooding. The granules are destroyed, so 

 that when the water is removed the soil bakes or is partly puddled, 

 and it becomes necessary to use some means for restoring the tilth. 

 This may be accomplished by turning under a green manure crop 

 or by an application of farmyard manure. 



Value of Alkali Land. Alkali lands include some of the most 

 valuable lands in the West, but more especially those that are 

 capable of being irrigated. They are worthless as they are, but 

 after the alkali is removed they have a very high value. Where 

 water may be had in abundance the cost of reclaiming is not exces- 

 sive. In doing this reclamation work drainage districts should be 

 organized similar to those in humid regions for draining swamp 

 land. The expense would in this way be reduced to a reasonable 

 amount per acre. 



Alkali Soils of Humid Regions. In areas where the rainfall 

 would seem to preclude the possibility of alkali, soils are sometimes 

 found to contain considerable amounts of soluble material. 



Dorsey e speaks of the patches of alkali at the Maryland Station, 

 where a thin layer of soil showed 1.83 per cent of water-soluble salts, 

 such as nitrates of calcium, magnesium, sodium, and potassium, 

 together with some chlorides and sul fates. 



