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faults of soils both of a dense and porous quality, it is of thegreatest importance to the husbandman to have this subject atcommand, in such abundance as to produce the desired effecton every field, in course, on which he finds it convenient to o-perate. Alternate courses of plants of a different character,that is to say, of culmiferous and leguminous plants, commonlycalled white and green crops, regularly succeeding each otherfrom year to year, and of tillage and grass crops, succeedingeach other, commonly called convertible husbandry, an economyvery generally adopted in Scotland , is well calculated for thispurpose. It was a very antient maxim among the cultivators ofland in Scotland , though it has frequently been ill observed,
Soiv peas and corn year about,
Andyou’ll never run land out.
An economy upon this principle has, however, of late, been re-duced to a regular system in some districts, where the climate ismost favourable, the soil happily constructed, and the cultivatorsactive and intelligent. By a strict attention to keeping the groundfree of all kinds of weeds, and the injurious effects of stagnantwater—by preserving the friability of the soil by the repeatedexercise of the plough and harrow—by the intervention of abroad-leafed crop, which overshadows the surface, and drawsmuch sustenance from the atmosphere, between two culmiferouscrops, which depend more on the soil for their support—by mak-ing the greatest possible quantity of manure from live stock care-fully tended and fed—and by carefully economizing this manure,so as to give every field its share in due rotation, the soil has beenpreserved in a state of undiminished productiveness for a num-ber of years, without scarcely ever resting in grass longer thanone year at a time. If this productiveness can always be preserv-ed by the same means—if the favourable consistence of the soilwill not at length be deranged by incessant culture—if the sameplants, naturally aliens of the country, will not become moreliable to fatal diseases by being long repeated in quick successionson the same fields—or if the land will not become weary of pro-ducing them, are questions which time must answer.
But there is not a great breadth of the country so happily cir-cumstanced. The quantity of manure which promotes a few*plentiful crops on those fertile fields, would scarcely have anysensible effect on many others. The manure which, by the strict-est economy, could be made from,all the live stock which couldbe supported on less fertile land, would be inadequate to whatplentiful crops would require, if the whole farm were constantlycropped. But, by putting one field after another in grass, be-fore the soil be exhausted by cropping, it yields a return pro.portioned to its fertility, without expense, its herbage is attract-ing food fi'om the atmosphere, and its powers are renovated. Infi;e mean time, the extent of cultivated land being curtailed, tip