190 



HORTICULTURE. 



Soiili ' clayey or afsandy loam. In the same way, in some 

 """V"*' counties of England chalky loams are common; and 

 in other districts, gravelly loams are not unfrequent. 

 When oxide of iron prevails, and renders the clay hard 

 and of a dark brown or reil colour, the soil is called 

 ferruginous loam, or more commonly tilL Boggy or 

 heathy soil consists of ligneous particles, or the decayed 

 roots, stems and leaves of various carices, heaths and 

 sphagna, and the coaly matter derived from these, ge- 

 nerally with a slight mixture of argillaceous earth and 

 sand. While the nomenclature of soils remains so im- 

 perfect and unsettled as it now is, there seems no pro- 

 priety in enlarging further on the different varieties. 

 Some judicious remarks on these, and on the principles 

 on which they should be distinguished and named, may 

 be found in the Agricultural Report of Ross and Cro- 

 marty, drawn up by Sir George Mackenzie, Bart. 



Carbonaceous matter, and certain salts, in small pro- 

 portion, are likewise ingredients in a good soil ; plants 

 deriving not only support from the soil, and nourishment 

 from the water and from the decomposition of the water, 

 supplied by the soil to their roots, but also other pecu- 

 liar sorts of food from the carbon and salts alluded to. 



43. Any substance added to a soil, either to supply 

 a deficiency or to rectify what is amiss, is called a ma- 

 nure. The use of manures is, of course, very various. 

 They may be destined to render soil less retentive of 

 moisture, or to make it more retentive ; or they may be 

 calculated to communicate carbonaceous matters or 

 salts. With the former view, clay or argillaceous marl 

 form a suitable manure for a sandy soil, and sand or 

 lime for one that is clayey ; while dungs and composts 

 of every kind yield the other requisite materials to the 

 soil. For opening clayey soils in gardens, marls are 

 excellent, particularly gravelly marl. Where marls 

 cannot be had, shelly sand, coal-ashes, or wood-ashes 

 mixed with chips of wood, may be resorted to. For 

 binding sandy soils, argillaceous marls or calcareous 

 loams are proper; and the scourings of ditches are of- 

 ten, for this purpose, valuable. 



The improvement of cold or sour clay is sometimes 

 effected by scorifying it, or burning it, as it is common- 

 ly termed. The sward, with two or three inches of the 

 clay adhering to it, is collected in heaps, and brought 

 into" 1 a state of red heat, by means of furze, peat or 

 coals, taking care to add clay on the exterior so as to 

 confine the fire. Acids and vegetable matters of noxi- 

 ous tendency seem thus to be driven off, and a soil fit 

 for garden culture produced. This is an old practice 

 which has been lately revived. In Hitt's Treatise on 

 Fruit-trees, published in 1758, there is a chapter " Of 

 the burning of clay for the improvement of land." 



44. The soil of a garden should never be less than 

 two feet and a half deep; the best gardeners prefer 

 having it fully three feet. The natural soil, therefore, 

 however good, is seldom of sufficient depth. If it be 

 not two feet, a quantity of earth from the fields is car- 

 ried in. The cleanings of roads and grass-turf of any 

 kind, form valuable additions to garden soil. In the 

 course of trenching, a portion of the subsoil is brought 

 to the surface, and gradually meliorated ; but to bring 

 up much of it at once, is very injurious. Soil of the 

 usual depth may be trenched two spit (spadeful) deep ; 

 and if this be done every third year, it is evident that 

 the surface which has produced three crops, will rest 

 for the next three years ; thus giving a much better 

 chance of constantly producing healthy and luxuriant 

 crops, and with one half the manure that would other- 

 wise be ^requisite. Nicol insists for the deeper soil, 



and recommends that, after taking three crops, the Soils, 

 ground should be trenched three spit, by which the s ~""Y-~ 

 bottom and top are reversed ; three crops are again to 

 be taken, and the ground trenched two spit, by which 

 the soil which formed the top goes to the middle, and 

 thi't v.-hk-h lay in the middle goes to the surface. Af- 

 ter other three crops, the trenching is to be again three 

 spit deep. By thus alternately trenching two spit and 

 three, after intervals of three years, the surface soil is 

 regularly changed, resting six years and producing 

 three ; and an approach is thus made to the desirable 

 object of having always a new soil. 



It is agreed on all hands, that nothing contributes 

 more to the preserving of the soil of a garden in good 

 condition, than exposing it as often as possible to the ac- 

 tion of the sun and air. It is a rule, therefore, that 

 garden ground, when not in crop, should regularly be 

 dug rough, or if possible ridged up, and left in that state 

 to the influence of the atmosphere. If it be allowed 

 botli a winter and a summer fallow, the oftener a new- 

 surface is exposed the better ; after it has lain ridged 

 up during winter, therefore, repeated diggings are given 

 in the spring and summer months. Whether some noxi- 

 ous matter be exhaled, or some fertilizing substance be 

 imbibed, or what may be the precise nature of the ope- 

 ration that goes on, we do not here inquire. The (act 

 is certain, that aeration, as it is sometimes called, is of 

 the greatest advantage to garden soils. 



45. It has been already remarked, that it is desirable to Mould, 

 have soils of different quality in the garden. One of 



the most generally desired is what is called mould, by 

 which is meant a soil in which vegetable earth predo- 

 minates. Such as is of a bright chesnut colour is pre- 

 ferred : it is usually styled by gardeners, hazelly mould, 

 or hazelly loam, from being of the colour of the hazel 

 nut. The characters of the best mould, according to 

 Miller, is, that " it cuts like butter, does not stick ob- 

 stinately, but is short, tolerably light, breaking into 

 small clods, is sweet, well tempered, without crusting 

 or chapping in dry weather, or turning to mortar in 

 wet." It should be so open, as not to stick to the spade 

 or the fingers after a shower of rain. Dark grey and 

 russet-coloured moulds are likewise considered good ; 

 ash-coloured are commonly bad; yellowish red still 

 worse. Good moulds after being broke up by the spade, 

 or after rain, if the surface have been recently dug or 

 hoed, emit rather a pleasant smell. What are called 

 brick moulds or loams, are much esteemed both by the 

 gardener and the florist, as auxiliaries to mix with 

 other soils. 



For some purposes a sandy soil is wanted. In this 

 case, either the surface sand, from a sandy pasture, is 

 alone used, as it contains a considerable portion of ve- 

 getable matter, or if pure sea or river sand be employ- 

 ed, light rich mould, nearly in the proportion of one- 

 half, is mixed along with it. For a very great number 

 of plants, particularly in the flower garden, an excellent 

 soil is to be found in the turf of old pastures, and the 

 earth which adheres to the turf to the depth of six or 

 eight inches, mixed witli a portion of cow and horse 

 dung in a rotten state, laid together in a heap for at 

 least a year, and frequently turned over. This is a 

 compost, and naturally leads us to speak more particu- 

 larly on the subject of manures. 



Manures. 



46. Many authors have treated of manures, and given Manuftr. 

 theories of their beneficial action ; Fordyce, Hunter, 

 Cullen, Ingenhousz, Senebier, and others. The learned 



