XIV GRASSES OF BRITAIN. 



Improvement of the Soil hy laying down to Grass* 



" One of the most common methods of improving the land is that 

 of layiny down to grass. This may be done for two, three, or four 

 years only, or for an indefinite period of time. In the latter case, 

 the land is said to be laid down permanently, or to permanent pas- 

 ture. 



" Temporary pasture or meadow. — If the land be sown with 

 grass and clover-seeds, only as an alternate crop between two sow- 

 ings of corn, the effect is fully explained. The roots which are left 

 in the soil enrich the surface with both organic and inorganic matter, 

 and thus fit it for bearing a better after-crop of corn. 



" If, again, it be left to grass for three or five years, the same 

 effect is produced more fully, and therefore this longer rest from corn 

 is better fitted for soils wliich are poor in vegetable matter. The 

 quantity of organic matter which has accumulated becomes greater 

 every year, in consequence of the annual death of stems and roots, 

 and of the soil being more closely covered, but this increase is pro- 

 bably never in any one after-year equal to that which takes place 

 during the first. The quantity of roots which is produced during 

 the first year of the young plants' growth must, we may reasonably 

 suppose, be greater than can ever afterwards be necessary in an 

 equal space of time. Hence, one good year of grass or clover will 

 enrich the soil more in proportion to the 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 artificial 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 great- 

 est 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 



* Lectures on Agricultural Chemistry. By James F. W. Johnston, M. A. 



