54 IMPROVEMENT OF SOILS, CONSIDERED 



which in the improvement of clayey soils, and indeed of all soils which are 

 of too compact a texture, is not duly appreciated. It is evident that, by 

 means of draining and burning, any clayey soil may have its texture as much 

 improved as can be desired ; and though the expense of this may, in many 

 cases, be too great for application on an extensive scale, yet it may always 

 be adopted in kitchen gardens ; and often over the entire surface of the 

 grounds of small villas. It is indeed only by this kind of improvement 

 that the heavy clayey soils of many of the small villas in the neighbour- 

 hood of London can be at all rendered comfortable to walk on after rains 

 in summer, and throughout the whole of the other seasons ; or suitable and 

 agreeable for the cultivation of culinary vegetables and flowers. Claye} r soils 

 often contain iron, and the operation of burning them, by forming an insoluble 

 compound of iron and alumina, lessens the risk of the iron ever becoming 

 noxious to the plants. Burning also destroys the inert vegetable fibre ; and 

 thus it at once produces ashes containing vegetable alkali, and supplies the soil 

 with a portion of humus ; without both of which, according to Liebig, no 

 soil can bring plants to maturity. Where a strong clayey soil is covered with a 

 healthy vegetation, as of pasture or wood, it may not be desirable to burn the 

 surface soil, on account of the quantity of organic matter which it contains ; 

 but it may still be very desirable to burn such a portion of the clayey subsoil 

 as may be sufficient, when reduced to a sandy powder, to render the surface 

 soil of a proper texture. In this case the surface soil should be removed to the 

 depth to which it has been cultivated, and a portion of that below taken up in 

 lumps, and dried and burned. The burning is performed on the spot by the 

 aid of faggot- wood, or any description of cheap fuel. The burned lumps 

 being reduced to a powder, and scattered equally over the soil when also in a 

 dry and powdery state, the whole should then be intimately mixed toge- 

 ther by repeated diggings and trenchings. As an example of the strong 

 clayey soil of a garden having been improved by burning, we may refer to 

 that of Willersley Castle, near Matlock, which the gardener there, Mr. 

 Stafford, has rendered equal in friability and fertility to any garden soil in 

 the country. " When I first came to this place," says Mr. Stafford, " the 

 garden was for the most part a strong clay, and within nine inches of the 

 surface ; even the most common article would not live upon it ; no weather 

 appeared to suit it at one time being covered by water, at another time 

 rendered impenetrable by being too dry. Having previously witnessed the 

 good effects of burning clods, I commenced the process, and produced in a 

 few days a composition three feet deep, and equal, if not superior, to any 

 soil in the country." (Hort. Reg. vol. i. p. 210.) The success was here 

 greater than can be expected in every case, because the clay contained a 

 large proportion of calcareous matter. 



175. Pulverizing soils comes next in the order of improvement, and is 

 effected by trenching, digging, and other modes of reversing the surface and 

 mixing and transposing all the different parts. By changing the surface, 

 fresh soil is exposed to the action of the weather ; by changing the position 

 of all the parts, new facilities for chemical changes are produced ; and by 

 loosening the whole mass of the soil, air and rain are more readily admitted, 

 and greater freedom is given to the growth of the roots. By loosening soil 

 the air is admitted among its particles and confined there, and hence it 

 becomes a non-conductor of heat, and is consequently warmer in winter 

 and cooler in summer than if it were in one firm mass. By the con- 



