LAYING DOWN TO GRASS. — PERMANENT PASTURE. 425 



time expended^ than a rest of two or three years in grass, if annually 

 'mowed. 



Or if, instead of being mown, the produce in each case be eaten off 

 by stock, the result will be the same. That which lies longest will be 

 the richest when broken up, but not in an equal proportion to the time 

 it has lain. The produce of green parts, as well as of roots, in the ar- 

 tificial grasses, is generally greatest during the first year after they are 

 sown, and therefore the manuring derived from the droppings of the 

 stock, as well as from the roots, will be greatest in proportion during the 

 first year. That farming, therefore, is most economical — where the 

 land will admit of it — ^ which permits the clover or grass seeds to occupy 

 the land for one year only. 



But if, after the first year's hay is removed, the land be pastured for 

 two or three years more, it is possible that each succeeding year may 

 enrich the surface soil as much as the roots and stubble of the first 

 year's hay had done ; so that if it lay three years it might obtain 

 three times the amount of improvement. This is owing to the cir- 

 cumstance that the whole produce of the field remains upon it, ex- 

 cept what is carried off by the stock when removed — but very much, 

 it is obvious, ^vill depend upon the nature of the soil, and upon the 

 selection of the seeds being such as to secure a tolerable produce of 

 green food during the second and third years. 



2°. Permanent pasture or meadow. — But when land is laid down 

 to permanent grass it undergoes a series of further changes, which 

 have frequently arrested attention, and which, though not difficult to 

 be understood, have often appeared mysterious and perplexing to 

 practical men. Let us consider these changes. 



a. When grass seeds are sown for the purpose of forming a per- 

 manent sward, a rich crop of grass is obtained during the first, and 

 perhaps also the second year, but the produce after three or four 

 years lessens, and the value of the pasture diminishes. The plants 

 generally die and leave blank spaces, and these again are slowly 

 filled up by the sprouting of seeds of other species, which have either 

 lain long buried in the soil or have been brought thither by the winds. 



This first change, which is almost universally observed in fields of 

 artificial grass, arises in part from the change which the soil itself has 

 undergone during the few years that have elapsed since the grass 

 seeds vv^ere sown, and in part from the species of grass selected not 

 being such as the soil, at any time, could permanently sustain. 



h. When this deterioration, arising from the dying out of the sown 

 grasses, has reached its utmost point, the sward begins gradually to 

 improve, natural grasses suited to the soil spring up in the blank places, 

 and from year to year the produce becomes greater and greater, and 

 the land yields a more valuable pasture. Practical men often say 

 that to this improvement there are no bounds, and that the older the 

 pasture the more valuable it becomes. 



But this is true only w.ihin certain limits. It may prove true for 

 the entire currency of a lease, or even for the lifetime of a single ob- 

 server^ but it is not generally true. Even if pastured by stock only and 

 never mown, the improvement wiW at length reach its limit or highest 

 point, and from this time the value of the sward will begin to diminish. 



