THE DRAINAGE OF GRASS LAND 9 



confined to those plants which possess Httle or no feedmg 

 value, and therefore regret need not be wasted on their 

 disappearance. And, as a rule, the work can be earned out at 

 a cost which will be returned with interest in the course of a 

 very few years. Drainage alone will go a long way towards 

 turning a marsh into a profitable pasture, and it renders other 

 improvements possible at a trifling expense. The important 

 point to be urged here is that undi-ained land should not be laid 

 down to grass. Otherwise careful tillage, costly manures, and 

 the finest grass seeds will certainly be wasted. The result is 

 only a question of time. Sooner or later the valuable grasses 

 which are sown will be supplanted by sedge and rush and 

 other semi-aquatic vegetation, until the pasture gradually 

 reaches the worthless condition which invariably prevails on 

 undrained land. 



Every year more water passes through land which is 

 naturally or artificially di'ained than through soil which is 

 generally saturated with moisture. Where stagnant water lies 

 no rain can enter : it simply runs off the surface by any outlet 

 it can find. The soil can neither breathe nor digest any 

 fertiliser applied to it, and it is incapable of utilising the sun's 

 heat for the development of plant life. 



When rain falls on a well-drained field it does more than 

 merely moisten the soil and supply plants Avith water. It 

 has been computed that in each year by means of rain 

 alone every acre of Avell-drained land in this country is 

 benefited to the extent of five to ten pounds of nitrogen. 

 Indeed, one of the advantages of good drainage is that it 

 allows the atmosphere to be freely carried into the soil 

 by rain, when the oxygen sweetens and converts injurious 

 organic substances into wholesome food for plants. At 

 the same time, carbonic acid gas derived from rain and air 

 performs the same operation for the mineral constituents of 

 the soil. 



