SOILS IN THE S ALTON BASIN. 109 



ens." The farmers of that neighborhood have considerable difficulty in managing 

 this soil, and it is not as refractory as much of the Imperial clay. Either annual 

 crops or crops which can be cultivated throughout the growing season are productive 

 of best results on this soil, for the heavy and hard crusts need to be broken up and 

 thoroughly pulverized occasionally. Alfalfa does not do well on such soil, for the 

 crusts seem too hard arid the soil too dense and impenetrable to permit the constant 

 extension of the fine rootlets so essential to permanency in an alfalfa field. Deep 

 plowing and thorough cultivation will in a few years greatly improve this soil." 



Practically none of the heavy clay soil is free from alkali, but some 

 45 per cent of this land in the surveyed area carries less than 0.4 per 

 cent of alkali, 6 and about 25 per cent more of the area occupied by 

 Imperial clay has from 0.4 to 0.6 per cent of alkali, where the date 

 will succeed as well, making some 70 per cent of this soil available for 

 the most remunerative date culture. The date palm can grow, but will 

 fruit less on 7.5 per cent more of the clay land even without drainage, 

 making in all about 77.5 per cent of this soil that is immediately avail- 

 able for date culture. The date can struggle along even without 

 artificial drainage on, perhaps, 75 per cent more of the area. 



The observations of Mr. D. G. Fairchild near Bassorah, on the Shat- 

 el-Arab River, at the head of the Persian Gulf, show that these great 

 date plantations, the most extensive in the world, are on u as pure an 

 adobe as the clay of a brickyard," and indicate the probability that 

 dates may be grown successfully on any heavy soils, provided the soils 

 be adequately drained and aerated. 



In the Bassorah date region the soil is automatically watered, drained, 

 and aerated by a system of ditches which fill from the river at high 

 tide and drain out again at low tide. 



In the Salton Basin and elsewhere in the United States it is prob- 

 able that drainage ditches or tile drains will be necessary to permit the 

 proper utilization of the heaviest clay soils. 



Messrs. Means and Holmes say: "Of the lands which are level 

 enough to permit profitable irrigation 17 per cent have to 0.2 per 

 cent of alkali, and are at present safe for cultivation to all ordinary 

 crops; 32 per cent have 0.2 to 0.4 per cent of alkali, which is risk} r for 

 ordinary crops; the remaining 51 per cent are too alkaline to be taken 

 up for any but alkali-resistant crops." That is to say, only 49 per 

 cent of the irrigable land in the surveyed area of the Salton Basin is 

 suitable for growing ordinary crops, whereas 76 per cent is available 

 for date culture. 



Means and Holmes. Field Operations of the Bureau of Soils, U. S. Department of 

 Agriculture, 1901, pp. 595, 596. 



* In soils of this nature, having a very fine texture and consequently a high water 

 capacity, a given percentage of alkali is not so injurious as in a sandy soil of low 

 water capacity, for the reason that the alkali forms a more dilute solution in the soils 

 which hold more water. (See p. 75. ) 



c Fairchild, D. G. Persian Gulf Dates and Their Introduction into America. 

 Bui. No. 54, Bureau of Plant Industry, U. S. Department of Agriculture, 1903. 



