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The "poison soils" of texas. — The Department has received a 

 number of letters from Texas describing a singular phenomenon fre- 

 quently occuring in the cultivation of tlie rich prairie soils of that 

 State. With these letters we have received several samples of the 

 soil spoken of, and have devoted much time and attention to a careful 

 examination of them. We make the following extract from a letter 

 written by G. W. Danover, of Breckinridge, Dallas County, Texas: 



* * * I send you a specimen of our poison soils. All our soils for many miles 

 in every clirection are of the same character, therefore I supposed one sj)ecimen would 

 be sufficient. There is no perceptible difference between the poison soil and that 

 which surrounds it. It is distinguished only by the premature decay of vegetation 

 growing upou it. It exists in limited areas, as far as I can learn, throughout the State, 

 in every variety of soil. Sometimes cotton covoriag 50 acres dies on one plantation. 

 We can never tell where it exists until we plant the ground in cotton, fruit-trees, or 

 root vegetables. The natural grasses, prairie and mesquite, grow well upon it. Tim- 

 othy and clover are not adapted to this soil and climate. Vegetation that derives 

 most of its vitality from the tap-root is more liable to die than that supported mainly 

 through lateral surface-roots. It does not affect, injuriously, cereals, corn, wheat, 

 &c. * * "f Trees usually grow one or two years before dying. Root vegetables 

 and cotton die and rot just before fully developing themselves. * * « The soil is 

 loamy when properly cultivated, but very tenacious when wet. It is underlaid with 

 a thick bed of soft limestone. This is called the " black sticky land." It produces 

 from 25 to 75 bushels of corn, and from one-fourth to one and a half bales of cotton, 

 ■when not affected by the poison, as we call it. * * * In procuring this speclmea 

 I removed the dirt four inches below the surface, then cut a slice ten inches deeper. 

 The difficulty doubtless lies some distance below the surface, from the fact that often 

 one stalk of cotton will die, and another standing almosit against it will grow luxuri- 

 antly. On examination their roots will be found to be different in structure, the dead 

 one having a straight root and the living one mostly lateral roots. 



The specimen of soil sent to the laboratory by Mr. Danover was very 

 dark colored — nearly black— with a slight brown shade, and so hard 

 that it was pulverized with difficulty. A preliminary qualitative exam- 

 ination showed nothing new or unusual in the soil; so the cause of its 

 peculiarity is to be found in the proportions of the ordinary soil ingre- 

 dients, or in the mariner in which they are combined. Subjecting a 

 sample of the soil, well pulverized, to the action of cold distilled water, 

 we found but nine hundredths of one per cent. (.09) soluble. Not fully 

 satisfied with these results, we determined, by an ultimate analysis, to 

 ascertain the exact composition of the soil as the only reliable method 

 of solving the problem. This analysis gave — 



Water determined at 100° C 7.100 



Carbonaceous matter and hydroscopic moisture 6. 964 



Humus, soluble in a solution of carbonate of soda 1. 673 



Insoluble humus, (extracted by caustic potassa) 0. 213 



Sesquioxides of iron and alumina 14. 096 



Phosphoric acid , 0. 206 



Lime 3.166 



Alkalies, (potassa and soda) 0.740 



Insoluble silica 63. 070 



Oxide of manganese 2, 072 



Loss , 0. 709 



100.000 



The first observable features in this analysis are the entire absence of 



sulphuric acid and the large per cent of humus which, in the fresh soil, 



evidently exists as humic acid in combination with lime and the alkalies 



constituting insoluble humates. This will account for the very smaU 



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