168 THE OX AND THE DAIRY. 



the herbage. It should not be ploughed in, but laid on the 

 surface two or three inches thick : chalk will also improve the 

 herbage. 



The usual time of letting on the water on water-meadows is 

 just before Christmas, and it may continue to flow over the 

 land as long as the frost lasts : in mild weather it may be 

 turned off during the day and put on again at night until the 

 frost is gone. The grass will soon begin to grow, and be 

 ready to be fed off. When this is done the water is imme- 

 diately let on for a short time, and turned off agajn, to allow 

 the ground to dry after a few days' flooding, and the water is 

 let on again at short intervals. The warmer the air is, the 

 shorter time must the water be allowed to cover the mea- 

 dows. As soon as the grass is five or six inches long it must 

 be left dry entirely till it is mown or fed off. In summer the 

 floodings must be very short, seldom more than twenty-four 

 hours at a time, but frequent. Thus a great weight of grass 

 may be obtained year after year without any manure being 

 put on the land, care being taken that, where the surface is 

 not quite even, the hollows be filled up with earth brought 

 from another place, or dug out of the drain, if that should be 

 partially filled up with the soil which the water has carried 

 into it. We alluded before to a case where water may remain 

 a considerable time on the land without injury ; this is, when 

 there are inundations from rivers, which rise above their beds 

 in spring, and cover the low meadows which lie along their 

 banks. In this case the grass, which has not yet sprung up, 



i is protected from the cold, and if there is a deposit from the 

 water there is a considerable advantage. But when it subides, 



i it must be made to run off entirely, without leaving small 

 pools, by which the grass would invariably be injured. Small 



| ditches or channels are usually dug, by which all the water 

 may run off, unless where the subsoil is very porous, or the 

 land is well under-drained, which is seldom the case in these 

 low meadows, for the drains would be apt to be choked by the 

 earthy deposit from the water. These inundations can some- 

 times be regulated by means of dykes and flood-gates, in 

 which case they partake of the advantages of irrigation, and 

 also of that deposition of fertilising mud which is called 

 warping. 



In the plan [fig. 1, p. 169) A A is a river which has a 

 considerable fall, and then flows through a level plain. A 

 considerable channel is cut at B where there is a rapid fall 



