200 CROPS FOR ALKALI LAND 



and where the crop is desired more as a means of reclaiming 

 the land for other crops in a few years, sweet clover is 

 preferable. It is an excellent green manure to be used in 

 upbuilding alkali land. 



Other Clovers. - The only other clover that has been 

 found to do well in the presence of large quantities of alkali 

 is berseem, or Egyptian clover. It has been found to 

 endure 4000 to 6000 parts per million of alkali, mostly 

 sodium chloride, under Egyptian conditions, but it has not 

 been used to any extent in this country. It requires mild 

 winters and is sensitive to cold. In Egypt it finds favor 

 in reclaiming alkali land because it withstands flooding 

 and an excessive water content of the soil 'which accompany 

 reclamation methods. Loughridge (19) found the limit 

 for burr clover to be about 1130 parts per million of black 

 alkali, which is exceptionally high for this salt. Crimson 

 clover and Birdsfoot clover both withstood 530 parts per 

 million, and white clover 630 parts per million of black 

 alkali according to this author. Red clover was not found 

 growing in concentrations greater than 670 parts per million 

 of total salts. 



Vetch ( Vicia saliva and V. villosa) has met with consider- 

 able favor in certain districts because it germinates well 

 on land which will not give a good stand of other resistant 

 crops without considerable trouble. Kearney (17) places 

 the limit for good germination between 4000 and 6000 parts 

 per million of white alkali, and Loughridge (19) found it 

 growing unaffected in a soil containing 4340 parts per mil- 

 lion of total salts, 160 parts per million sodium carbonate, 

 200 parts per million sodium chloride, and 3980 parts per 

 million of sodium sulphate. It may be used for pasture 

 or as a green-manuring crop, but since it does not do so 

 well under most alkali conditions and since other crops 



