Il6 SOILS. 



few hours of sunshine become of stony hardness and will resist 

 all efforts at pulverization or the production of tilth. 1 



Calcareous Clay Soils crumble on drying. The heavy clay 

 soils of some of the calcareous prairies of the Southwest, in- 

 stead of contracting into a stony mass on drying, on the con- 

 trary resolve into a mass of crumbs, thus producing excellent 

 tilth. This occurs even though the land may have been 

 plowed when wet, and of course is a great advantage. The 

 most striking exemplification of this peculiarity occurs in the 

 heavy but profusely fertile " buckshot " clay lands of the 

 Yazoo bottom, in Mississippi, where it is usual to plant corn 

 and sweet potatoes in the semi-fluid mud left after an over- 

 flow, after turning a shallow furrow, then covering by turn- 

 ing another. To the onlooker it seems impossible that such 

 plantings could be successful ; but within a short time the 

 muddy surface becomes a bed of crumbs ("buckshot"), 

 forming a seedbed not readily excelled by any made by arti- 

 ficial means. Hence, largely, the almost invariable success of 

 crops in the Yazoo region. 



Port Hudson Bluff. The same clay produces a most un- 

 pleasant result at the foot of the Port Hudson bluff, where it 

 crops out some feet above low water. When after a freshet the 

 water level falls below this stratum, on drying the clay dis- 

 integrates into crumbs just as does the Yazoo buckshot soil ; 

 with the result that at the next rise, the loose mass subsides into 

 the river as a flood of mud. Thus the foot of the bluff is 

 being constantly undermined, and the falling of the bluff scarp 

 has obliged the town above to recede many hundreds of feet 

 from its original historic site. 



The exact proportions of lime carbonate necessary to produce 

 this phenomenon, and its necessary relations to clay substance 

 and other physical soil ingredients, yet remain to be investi- 

 gated. 2 



1 In driving a light carriage over the land represented by No. 643 above, after a 

 light rain, the wheels gathered up so much soil within a hundred yards as to 

 render it necessary to stop and chop it off the tires by means of a hatchet. This 

 is a common experience in the black prairie lands of Texas. 



2 Schiibler (Grands'atze d.Agrikulturchemie, 1838) ascribes the crumbling of 

 calcareous clay soils to the difference in the contraction of calcareous sand and 

 the clay substance. But it is doubtless more directly connected with the floc- 

 culation of the latter by lime. 



