2 BULLETIN 135, U. S. DEPARTMENT OF AGRICULTURE. 



The land in the affected area is somewhat lower than the surround- 

 ing lands of the project and is generally rather level, being broken 

 only occasionally by slight depressions or natural-drainage wasteways. 

 Very little leveling is necessary in preparing the land for irrigation. 



The natural vegetation is a low, scattering growth of scrub sage and 

 saltbush and a very little grass. Throughout the entire area are 

 many small spots entirely barren of vegetation. The soil on these 

 barren spots bakes rapidly and becomes very hard after rains. 



The lower layers of the soil between the upper foot or two and the 

 underlying gravel contain very little moisture before irrigation 

 water is applied or before they are affected by the rise of ground 

 water. The ground water at the time this work was started in 1910 

 was 6 to 8 feet below the surface and occurred only in the underlying 

 gravel. This gravel stratum is apparently broken or contains so 

 much fine material that the water entering the soil from the irriga- 

 tion of higher lands can not be carried off as rapidly as it enters the 

 soil, and there has been a consequent rise of the ground water over 

 this area during the past two years. It rose during the season of 

 1913 to within about 3 feet of the surface. 



It appears that the problem involved in the reclamation of this 

 land is the opening up of the surface soil so as to make possible the 

 leaching out of the alkali salts either by the application of irrigation 

 water or by the rainfall. 



This soil is also very deficient in vegetable matter, and it appeared 

 that the addition of humus by plowing under green-manure crops 

 would be one of the best means of improving the physical condition 

 of the soil. Rye appeared to be the best crop for this purpose, as 

 it is able to produce a crop under rather adverse conditions. In the 

 fall of 1910 about 12 acres of the land on this tract were broken up 

 and planted to winter rye. This land lies in two fields. Field M-I 

 contains about 5 acres and field M-II about 7 acres. The rye crop 

 made a fair though rather irregular growth, and was plowed under 

 in June, 1911, when the plants were heading. On the 7-acre field 

 and on a part of the 5-acre field this treatment was repeated in 1912. 

 The second year's crop of rye was much heavier and more uniform 

 than the first. Each year after plowing the rye under, the land was 

 cultivated frequently after rains, to maintain a mulch and to prevent 

 the crusting of the surface. By this method the tilth of the soil 

 appeared to be much improved, and the amount of salt in the surface 

 soil, as shown by determinations made at different dates, was greatly 

 decreased. The land on which the green-manure treatment had 

 been applied for two years was cropped to winter wheat in 1913. 

 The wheat on field M-II yielded 28.7 bushels per acre and that on 

 field M-I 35 bushels per acre. Trials of alfalfa and sugar beets 

 were also made in 1913 on small plats that had received the green- 



