146 Irrigation and Drainage 



from the natural rainfall on pasture land, great care should be 

 taken to keep it in such condition that the whole surface is well 

 and closely covered with vegetation. Of course, the same remarks 

 apply to meadow lands. 



Too close pasturing is very wasteful in every way. The 

 animals themselves are not fed properly, the grass is not permitted 

 to have foliage enough for the most vigorous growth, and so much 

 of the surface of the ground is exposed to the sun that evapora- 

 tion directly from the soil is rapid and a dead loss, not only doing 

 no good in itself, but throwing out of use the upper layer of soil, 

 in which the nitrifying processes should be permitted to go for- 

 ward rapidly, because it is too dry for them. 



The surface dressing of meadows with a good coating of 

 farmyard manure, and then harrowing this thoroughly to spread it 

 evenly over the surface, is extremely beneficial, not simply because 

 of the plant-food which it contains, but because of the mulching 

 effect which it furnishes to shade the naked spots of soil and 

 those which are only thinly covered. When this dressing is 

 applied very early, and is early spread over the surface, while 

 the soil is yet damp, it, of course, does the most good, both as a 

 mulch and as a plant -food ; for then fermentation goes on better 

 in the manure, and the moisture dissolves out the soluble parts 

 and conveys it to the roots of the grass. Then, too, in the case 

 of thin meadows, if new grass and clover seed are added at the 

 same time, before the harrowing, much of it will be sufficiently 

 covered by the harrowing and shaded by the manure to allow it to 

 germinate, and thus thicken up the meadow and bring it back to 

 its proper condition. 



Harrowing and rolling small grain after it is up. When the 

 ground is closely covered with plants, as in the case of oats, 

 wheat and barley sowed broadcast or in close drills, advantage 

 has sometimes been found in either harrowing the ground or in 

 rolling it for the express purpose of changing the character of the 

 surface. The changes thus wrought have sometimes a double 

 effectiveness, in that a thin mulch is produced which in a meas- 

 ure reduces the direct loss of water through the surface soil by 

 .evaporation from it ; and in breaking up a crust which forms 



