Book VI. ROTATION OF CROPS. 799 



other plants, such as peas, tares, cabbages, and carrots, occupy a part, though commonly but a small part, 

 of that division of a farm which is allotted to green crops. This order of succession is called the system of 

 alternate husbandry ; and on rich soils, or such as have access to abundance of putrescent manure, it is 

 certainly the most productive of all others, both for food for man and for the inferior animals. One half 

 of a farm is in this course always under some of the different species of cereal grasses, and the other half 

 under pulse, roots, cultivated herbage, or plain fallow. 



4930. But the greater part of the arable land of Britain cannot be maintained in a fertile state under 

 this management; and sandy soils, even though highly manured, soon become too incohesive under a 

 course of constant tillage. It therefore becomes necessary to leave that division ox break that carries cul- 

 tivated herbage to be pastured for two years or more, according to the degree of its consistency and fer- 

 tility ; and all the fields of a farm are treated thus in their turn if they require it. This is called the 

 system of convertible husbandry, a regular change being constantly going on from aration to pasturage, 

 and vice versa. 



4931. Not to repeat the same kind of crop at too short intervals, is another rule with regard to the sue 

 cession of crops. Whatever may be the cause, whether it is to be sought for in the nature of the soil or 

 of the plants themselves, experience clearly proves the advantages of introducing a diversity of species 

 into every course of cropping. When land is pastured several years before it is brought again under the 

 plough, there may be less need for adhering steadily to this rule ; but the degeneracy of wheat and other 

 corn crops recurring upon the same land e\ ery second year for a long period, has been very generally ac- 

 knowledged. It is the same with what are called green crops ; beans and peas, potatos, turnips, and in 

 an especial manner red clover, become all of them much less productive, and much more liable to disease, 

 when they come into the course, upon the same land, every second, third, or fourth year. But what the 

 interval ought to be has not yet been ascertained, and, from the great number of years that experiments 

 must be continued to give any certain result, probably cannot be determined until the component parts of 

 soils, and particularly the sort of vegetable nourishment which each species of plant extracts from the 

 soil, have been more fully investigated. 



4932. A change qf variety as well as of the species, and even of the plants of the same variety, is found 

 to be attended with advantage ; and in the latter case, or a change of seed, the species and variety being 

 the same, the practice is almost universal. It is well known, that of two parcels of wheat,'for instance, as 

 much alike in quality as possible, the one which had grown on a soil differing much from that on which 

 it is to be sown, will yield a better produce than the other that grew in the same or a similar soil and cli- 

 mate. The farmers of Scotland accordingly find that wheat from the south, even though it be not, as it 

 usually is, better than their own, is a very advantageous change ; and oats and other grain brought from 

 a clayey to a sandy soil, other things being equal, are more productive than such as have grown on sandy 

 soil {Supp. Encyc. Brit. art. Agr. 144.) 



4933. The following are examples of rotations suited to different soils, as given in Brown's 

 excellent Treatise on Rural Affairs. The basis of every rotation, he says, " we hold to 

 be either a bare summer fallow, or a fallow on which drilled turnips are cultivated, and 

 its conclusion to be with the crops taken in the year preceding a return of falloAv or drilled 

 turnips, when of course a new rotation commences. 



4934. notation for strong deep lands. According to this rotation, wh^t and drilled beans are the crops 

 to be cultivated, though clover and rye-grass may be taken for one year m place of beans, should such a 

 variety be viewed as more eligible. The rotation begins with summer fallow, because it is only on strong 

 deep lands that it can be profitably practised ; and it may go on for any length of time, or so long as the 

 land can be kept clean, though it ought to stop the moment that the land gets into a contrary condition. A 

 considerable quantity of manure is required to go on successfully ; perhaps dung should be given to each 

 bean crop; and if this crop is drilled and attentively horse-hoed, the rotation may turn out to be one of 

 the most profitable that can be exercised. 



4935. Rotation for loams and clays. Where it may not be advisable to carry the first rotation into 

 execution, a different one can be practised, according to which labour will be more divided, and the usual 

 grains more generally cultivated j for instance, the following, which used to be common in East Lo- 

 thian : 



1. Fallow, with dung. 4. Barley. 7. Beans drilled and horse-hoed. 



2. Wheat. 5. Clover and rye-grass. 8. Wheat. 



3. Beans, drilled and horse-hoed. 6. Oats or wheat. 



This rotation is excellently calculated to insure an abundant return through the whole of it, provided 

 dung is bestowed upon the clover stubble. Without this supply the rotation would be crippled, and 

 inferior crops of course produced in the concluding years. 



4936. Rotation for clays and loams of an inferior description. This rotation is calculated for soils of an 

 inferior description to those already treated of. 



1. Fallow, with dung. 3. Clover and rye-grass. 5. Beans, drilled and horse-hoed. 



2. Wheat. 4. Oats. 6. Wheat. 



According to this rotation, also in use in East Lothian, the rules of good husbandry are studiou.sly practised ; 

 while the sequence is obviously calculated to keep the land in good order, and in such a condition as to 

 ensure crops of the greatest value. If manure is bestowed either upon the clover-stubble or before the 

 beansare sown, the rotation is one of the best that can be devised for the soils mentioned. 



4937. Rotation for thin clays. On thin clays gentle husbandry is indispensably necessary, otherwise the 

 soil may be exhausted, and the produce unequal to the expense of cultivation. Soils of this description will 

 not improve much while under grass ; but unless an additional stock of manure can be procured, there is 

 a necessity of refreshing them in that way, even though the produce should in the mean time be compa- 

 ratively of small value. The following rotation is not an improper one : 



1. Fallow, with dung. 3. Grass pastured, but not too early eaten. 5. Grass. 



2. Wheat 4. Grass. 6. Oats. 

 This rotation may be shortened or lengthened, according to circumstances, but should never extend 

 further in point of ploughing than when dung can be given to the fallow-break. This is the keystone of 

 the whole; and if neglected the rotation is rendered useless. 



4938. Rotation for peat earth soils. These are not friendly to wheat, unless aided by a quantity of cal- 

 careous matter. Taking them in a general point of view, it is not advisable to cultivate wheat, but a 

 crop of oats may almost be depended upon, provided the previous management has been judiciously exe- 

 cuted. If the subsoil of peat earth lands is retentive of moisture, the process ought to commence with a 

 bare summer fallow ; but if such are incumbent on free and open bottoms, a crop of turnips may be sub- 

 stituted for fallow ; according to which method, the surface will get a body which naturally it did not 

 possess. Grass on such soils must always occupy a great space of every rotation, because physical cir- 

 cumstances render regular cropping utterly impracticable. 



1. Fallow, or turnips with dung. quantity of perennial rye- circumstances permit the land to 



2 Oats of an early variety. grass. be broken up, when oats are to be 



i. Clover, and a considerable 4. Pasture for several years, till repeated. 



