318 AGRICULTURAL REPORT. [TG88, G89 



Insoluble Matter (as above) 79.477 



Potash 0.741 



Soda 0.248 



Lime 0.238 



Magnesia 0.830 



Brown Oxide of Manganese 0.346 



Peroxide of Iron 5.634 



Alumina 8.849 



Phosphoric Acid 0.092 



Sulphuric Acid trace 



Organic Matter and Water 3.496 



100.038 



688. No. 237. Calcareous Silt, from James Watson's place, five and a half 

 miles north-east of Port Gibson, Claiborne county. 



Depth : Was taken on the hillside, about four feet from the surface, and about 



ten feet below the highest point at which it is visible here. 



Vegetation: Hillside growth similar to that described above, (T[684 2 ); mixed 



with oaks. 



Saturated with moisture at 68 deg. Fahr.. it lost 4.118 per cent, of its weight 



at 400 deg. Fahr. Dried at this temperature, it consisted of : 



Insoluble Matter 75.344 



Potash 0.511 



Soda 0.115 



Lime 5.921 



Magnesia 3.278 



Brown Oxide of Manganese 0.252 



Peroxide of Iron 3.272 



Alumina 2.823 



Phosphoric Acid 0.145 



Sulphuric Acid 0.060 



Carbonic Acid 6.729 



Organic Matter and Water 1.231 



99.681 



689. A comparison of the first two analyses shows the important fact, that 

 the subsoil is considerably richer than the surface soil, in several important 

 ingredients. It contains nearly one-third of a per cent, more Potash, twice the 

 amount of Soda, an equal amount of Lime, one-third of a per cent, more Mag- 

 nesia — the latter ingredient being, however, not deficient in the surface soil 

 itself. With respect to Phosphoric and Sulphuric Acids, the advantage is on 

 the side of the surface soil. 



Were it only, however, for the large excess of potash contained in the subsoil, 

 and the improvement of the physical properties which would be effected in the 

 light surface soil by an admixture of the heavier subsoil, that alone would suffice 

 to render subsoiling a very important improvement. The upland soils of the 

 region in question have been esteemed very fertile, notwithstanding that the 

 amount of Potash and Phosphoric Acid contained in them (if the soil analyzed 

 be a fair specimen), is rather below that of a good average soil ; and that in but 

 a few cases as yet, the tillage has extended to a greater depth than that at which 

 the above specimen was taken. It is probable, thorefore, that although a large 

 part of these upland soils is now considered as exhausted, or approaching 

 exhaustion, the richest part of the surface layer within reach of the plow, has 

 hardly been more than touched. It would appear also, from the productiveness 

 of a surface soil comparatively poor, that the nutritive ingredients contained in it 

 are, to a great extent, in an available condition. 



