ARTIFICIAL FIELDS 



haulm, is always worth looking at, and particularly in the 

 early morning when it is beset with sparkling drops of dew. 



It is all wiry, bending and swaying to the wind so as to 

 produce those waves which roll across a hay-field, and on 

 which the shimmering light is reflected and changes colour. 

 The fight for light and air, the struggle to get their heads 

 up above their competitors, produces all this exquisite 

 mechanism. 



It is true that a heavy rainstorm may beat the stems flat 

 down to the ground, but, as soon as the weather becomes dry 

 again these same stems will raise themselves up and become 

 upright ; they have a special sensitiveness and a special 

 kind of growth which enables them to do this. 



There are two special dangers which all such artificial 

 meadows have to withstand. Let us see what will happen if 

 such a meadow begins to dry up through a sinking of the 

 level of the water below the soil. 



Each grass has its own special favourite amount of mois- 

 ture. It likes to have its water at just one particular depth 

 below the surface. Unfortunately there are not nearly 

 enough sympathetic and careful observations of the pre- 

 ferenees of each individual grass. A Danish author has 

 worked out the facts in certain localities (Geest). Suppose 

 first that the water-level of the wells, etc., is 6 J to 9| feet 

 below the surface. This suits the Meadow Poa grass {Poa 

 pratensis) exactly. It will grow luxuriantly and flourish. 

 Now suppose the weather is very wet, so that the water rises 

 in the wells till they are three to four feet deep. The 

 Roughish Poa (P. trivialis) prefers this moister soil, and it 

 will grow so vigorously that it will kill out the other kind. 

 If it is a season of very heavy floods, or if the drains become 

 choked so that the water rises to within fourteen to twenty- 



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