MIXTURE OF SOILS. 



MIXTURE OF SOILS. 



Devon dredge for the sand at the mouth of the 

 Tamar, and when they have filled their barges, 

 carry it up the river. They deem the fine- 

 grained sand the most immediate in its effects, 

 but both are very durable, and decided im- 

 provements to the soil. The coarse sand, they 

 say, lasts for many years. 



The composition of the sands of Padstow 

 Harbour, and of the estuary of the Tamar, are 

 very similar ; they contain from 60 to 70 per 

 cent, of carbonate of lime, and are both pre- 

 ferred by the farmers, when they can be ob- 

 tained, mixed with the sea-water. 



Another, but the least commonly practised 

 mode of improving the staple of a soil by earthy 

 additions, is claying ; a system of fertilizing, 

 the good effects of which are much less im- 

 mediately apparent than chalking, and hence 

 one of the chief causes of its disuse. It re- 

 quires some little time to elapse, and some 

 stirring of the soil, before the clay is so well 

 mixed with a sandy soil as to produce that 

 general increased attraction and retentive 

 power for the atmospheric moisture which 

 ever constitutes the chief good result of clay- 

 ing poor soils. Clay must be, moreover, ap- 

 plied in rather larger proportions to the soil 

 than chalk; for not only is its application 

 rarely required as a direct food for plants, for 

 the mere alumina which it contains, since this 

 earth enters into the composition of plants in 

 very small proportions, but there is also another 

 reason for a more liberal addition of clay being 

 required, which is the impure state in which 

 the alumina exists in what are commonly 

 called clay soils. For instance, chalk usually 

 contains, when perfectly dry, about 98 per cent, 

 of carbonate of lime. Mr. Kirwan found in a 

 specimen of chalk 2 per cent of alumina, or 



Lime - 



Carbonic acid - 

 Water 

 Alumina 



52 



42 



3 



S 



100 



But the heaviest clay soils seldom contain 

 more than 20 per cent, of alumina ; in the stiff 

 clays of Sussex and the Weald of Kent are 

 found only about 28 per cent, of this earth : 

 even the adhesive clays employed by the potter 

 yield only about 33 per cent, of alumina, porce- 

 lain earth only 47 per cent. 



The following is the analysis of a heavy 

 Sussex clay soil : 



Silica - - - - 

 Alumina - 

 Carbonate of lime 

 Oxide of iron 

 Organic matters 

 Loss, chiefly moisture 



Parts. 

 54 

 28 

 3 

 5 

 4 

 3 



100 



The farmer, therefore, who applies 50 tons 

 per acre of such a clay to a sandy "field, only 

 adds about 14 tons of alumina to the soil ; but 

 if he applies 50 tons of chalk, he adds 49 tons 

 of carbonate of lime. 



Hence, is the reason why, in all efforts to 

 alter the earthy constituents of a soil, a much 

 smaller quantity of chalk produces more de- 



cided effects than the addition of a much larger 

 proportion of the most tenacious clay. Chalk, 

 too, when merely spread on the surface of the 

 soil, and exposed to the action of froit, speedily 

 crumbles to powder, and becomes intimately 

 combined with the other earths of the soils. 

 The clay, however, is too adhesive to be thus 

 readily, and without some little labour, so inti- 

 mately mixed with the soil : its effects, how- 

 ever excellent, are much more slowly appa- 

 rent; but patience and judicious management 

 of clay will do wonders, even on the most un- 

 likely soils; and I could not, perhaps, state any 

 more complete cases of the recovery of an 

 absolutely barren soil by means of clay and 

 chalk, and that, too, at a reasonably profitable 

 rate, than those successful experiments which 

 have recently been made on the shingle of the 

 sea-coast near Eastbourn, in Sussex, consist- 

 ing entirely of silicious pebbles, varying in 

 size from that of hazel-nuts to hen's eggs, and 

 that extending to a depth of many feet. 



In this case the clay was drawn in hand-carts 

 by three men, rather better than a quarter of a 

 mile. The cart contained about 880 Ib. of clay, 

 or about 13 cubic feet. Eight of these cart- 

 loads, or about 3J tons, were spread on each 

 square rod of 16 feet, which, when first spread 

 loosely and in lumps, made the soil 5 or 6 

 inches deep, and when it had become settled 

 and solid, about 4 inches ; each cart took back 

 a load of shingle to fill up the hole made by 

 the excavation of the clay. The work was la- 

 borious, but the men readily earned about Is.Grf. 

 per day, and were contented. They did their 

 work by contract, receiving 3s. per square rod 

 for the shingle they thus covered, or 24/. per 

 acre ; and for this sum they carried 250 tons 

 of clay. The clay is of the oidinary red de- 

 scription, so common in Sussi *, and though 

 not particularly adhesive, is yet sufficiently so to 

 form a plate, on which in wet weather the water 

 stands, although this superstructure of clay is 

 resting on a mass of coarse shingle stones, 15 

 feet in depth. This experiment was made on 

 a small field of about 3 acres in 1839, and 

 promises as well as a similar effort made with, 

 the same clay in 1832. 



In this instance an acre and a quarter of 

 shingle was covered with the same clay to a 

 similar depth. But the clay being only divided 

 in this case from the shingle by the Eastbourn 

 and Hastings Road, the expense was less ; the 

 men digging, carrying, and spreading the clay, 

 for 2s. per rod, or 161. per acre. This land was 

 let in 1834, for a term of 14 years, at 40s. per 

 acre. The tenant has succeeded in making it 

 produce excellent crops ; has added to it a con- 

 siderable quantity of muck and ditch scrapings ; 

 has paid his rent regularly, and is contented 

 with his bargain : it produced, in 1838, an ex- 

 cellent crop of rye, which was cut green for 

 horses ; this was followed by a good crop of 

 potatoes, and in 1839, the tares which it pro- 

 duced were a very heavy crop. It is rated to 

 the poor at 21s. Sd. per acre. 



It would be hardly possible, I think, to pro 

 duce a more complete case of the absolute for- 

 mation of a soil, by means of claying, than 

 these valuable experiments ; the soil (if utterly 

 barren boulder stones or large shingle thrown 



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