382 Improvement of Grass-land on the 



yond 4 or 5 inches. Naturally, the soil was either like a soapy 

 cheese or a brickbat. 



Submitted to chemical analysis, a fair average sample of the 

 unimproved soil, previously dried in a water-bath at 212^ Fahr., 

 yielded the following results in 100 parts : — 



Composition of Oxford day soil (iinimproved pasture at Braydoii). 



Surface soil, dried at 212°. 



Organic matter and water of combination .. .. 15"13 



Oxides of iron and alumina 13'05 



Lime -29 



■ Magnesia '26 



Potash '56 



Soda -09 



Snlphnric acid "17 



Insoluble silicious matter and loss 70*45 



100-00 



It appears from the above that this soil is free from any consti- 

 tuent inimical to vegetation, and that it does not contain any sub- 

 stance in large excess. There is a considerable proportion of clay'; 

 but the sterility of Braydon cannot be due to a preponderance of 

 clay, inasmuch as there are fertile soils into the composition of 

 which clay enters in much larger proportion. Indeed, the soil 

 contains a great deal of fine micaceous sand, and it is owing to 

 this coming in contact with a comparatively small portion of 

 clay that the surface bakes up so much. It is well to bear in 

 mind that fine sand and some clay runs into a closer, heavier, 

 and certainly less productive soil than agricultural clays which 

 are almost free from sand. Many poor, hard soils, classed as 

 clays, which are difficult and very expensive to work, contain 

 scarcely 16 per cent, of true clay, the remainder being sand. 

 Such soils are not much improA'ed by weathering, for they con- 

 tain but little matter which on exposure to air yields food to 

 plants, but nearly four or five times as much fine sand as clay : 

 hence they are less benefited by cultivation and aeration than 

 even land of almost pure sand, and are best suited for grass after 

 thorough drainage. 



The sterility of the pasture land at Braydon appears to be due 

 mainly to two causes, namely, 1st, to want of drainage ; 2nd, 

 to the poverty of the clays, or the admixture of a large pro- 

 portion of fine and all but useless micaceous sand with the clay 

 proper. It may be further observed that in this soil most of the 

 " iron " occurs as protoxide, a sure indication of imperfect circu- 

 lation of air in the soil. 



Efficient drainage not only removes the evil of stagnant water, 

 but carries air into the soil, as is evidenced by the alteration 

 from the dull yellowish colour which distinguishes illdrained 



