98 BOTANICAL GAZETTE [febrttaky 



and phosphorus. Samples 15 and 16 were taken a few rods apart, 

 the former from a field which had been in alfalfa for several years, 

 and the latter from virgin land. Both have practically the same 

 phosphorus content, but the sulphur is much higher in the virgin 

 soil. 



All the soil samples from Kentucky (nos. 19-34) are residual 

 limestone soils, but no. 34 was derived from the Trenton limestone, 

 which is high in phosphorus, while the others are all from the 

 Cincinnati limestone, but no. 28 was taken from soil derived 

 from Cincinnati limestone, but it was only a short distance from 

 the division line between the Cincinnati and Trenton formations, and 

 had probably received some material from the Trenton formation. 

 Samples 19-27 are from Mason County, while samples 28-34 are 

 from Mercer County. Samples 19 and 21 are clay loams, while 20 

 and 22-27 3.re silt loams. All are Hght brown to grayish brown in 

 color. Sample 34 is a heavy clay loam, sample 28 is a heavy silt 

 loam or light clay loam, while samples 29-33 ^.re silt loams. 

 Samples 31 and 33 are quite gray in color, and $t, contains iron 

 concretions. No. 31 is known locally as whitQ oak land, and both 

 are recognized as poor soils. All the other samples are light brown 

 except no. 34, which is a grayish brown. All the Kentucky soils 

 are low in volatile matter except the clay loams, in which part of 

 the volatile matter is probably water of combination. All are low 

 in sulphur, no. 34 being the only one above 0.03 per cent. This 

 sample is from the Trenton formation and contains many un- 

 weathered fragments of limestone. It is possible that the sul- 

 phur content as well as the phosphorus content of the Trenton 

 limestone may be higher than in other formations. No. 34 con- 

 tains 0.3407 per cent of phosphorus, which is eleven times as great 

 as the sulphur content. This is much higher than any of the others, 

 but all the others are high in phosphorus. 



Relation between amounts of sulphur and phosphorus 

 removed by crops and sulphur and phosphorus contents of 

 SOILS. — A better idea of the supply of sulphur and phosphorus in 

 the soil can be obtained if the pounds per acre of these elements 

 found in the surface soil is compared with the amounts removed by 

 some of our common crops. Table II gives the amounts of sulphur 



