192 Fruit-growing in Arid Regions 



shade afforded by the plants, but to the transpiration of 

 immense quantities of water as well. It has been found, 

 for example, that a grass plant will give off its own weight 

 of water every twenty-four hours in hot, dry summer 

 weather. To be sure, it requires more water to irrigate an 

 orchard when any crop other than the trees is grown, 

 but when sufficient water can be had, this feature need 

 not be considered. 



It is well known that our heavier soils, particularly 

 if they are strongly alkaline, become so compact that it is 

 almost impossible to till them after the first irrigation 

 in the spring. It is also true that continued clean tillage, 

 particularly if plowing is omitted, will make almost any 

 of our soils compact. It is this condition that prevents 

 the proper development of absorbing roots and the setting 

 free of the native fertility of the soil. A few of our fruit- 

 growers have shown that green-manures in combination 

 with the necessary plowing will work wonders with such 

 soils as well as with the appearance of the trees growing 

 on them. 



Earthworms do damage in some orchards for the 

 reason that they puddle the soil, and much of the irriga- 

 tion water seems to disappear through the channels 

 that they make deep in the ground. A supply oif de- 

 caying organic matter should do much to overcome these 

 defects. 



Soils are occasionally found which are so porous that 

 water leaches through them much as if through a sieve. 

 If fiber can be incorporated in such land by plowing 

 under green-crops, this tendency to leach will be overcome, 

 to a certain extent at least. 



