DRYLAND FARMING. 347 



of plant food available, and the soil is made more receptive 

 for rain. 



When a crop is growing, a good deal of the moisture that 

 would escape through upward capillary action is utilised by the 

 root-hairs before it reaches the surface. 



The Illinois Station, conducting experiments with maize 

 to ascertain the value of mulches, obtained the following 

 results, as an average for nine years : — 



(1) Land ploughed, prepared, planted, and receiving no 

 further treatment — 7 "4 bushels per acre. 



(2) Ploughed, prepared and, cultivated — 43'4 bushels per 

 acre. 



(3) Ploughed, prepared, weeds scraped off with a sharp 

 hoe, and no cultivation — 48'9 bushels per acre. 



Chilcott states that : " Numerous experiments made in 

 connection with this work have furnished an abundance of 

 evidence that when vegetative grow^th is restrained the loss of 

 water from a mulched surface is practically the same as from 

 an unmulched one. 



The cheapest and most efficient methods of weed destruc- 

 tion necessarily form a soil mulch. The results accruing from 

 the prevention of weed growth have been very generally 

 attributed to the mulch itself, when the mulch is, in fact, only 

 incidental." 



KuN-OFF. — In South Africa, on account of our torrential 

 rainfall, this is frequently a very serious loss, particularly in 

 mountainous and undulating parts. The loss may vary from 

 10 to 75 per cent, of the rainfall, according- to its nature and 

 distribution, the topography of the land, the character of the 

 soil, and the amount of vegetation present. 



Heavy rainfall on summer fallowed land will often form 

 a relatively impervious layer, over which the run-off is extra- 

 ordinarily large. Dr. Shantz supplies the following data 

 obtained in the Western States : — 



(1) (a) Summer tilled plot — 48 per cent, retained by the 

 soil. 



(h) Adjacent plot under grass-sod — 86 per cent, retained 

 by the soil. 



(2) (a) Land covered with w^heat stubble — IJ- inches 

 absorbed out of 4 inches total. 



