16 Fruit-growing in Arid Regions 



on this kind of land, it is difficult to keep them in good, 

 condition. 



The one thing that all semiarid soils is liable to be 

 lacking in is organic matter. The climatic conditions 

 are such that this important soil constituent is rapidly 

 exhausted, and many orchards, particularly in the newer 

 sections, are planted on desert land that was given no 

 preparation except clearing and plowing a few furrows 

 for the tree rows; the space between the rows was plowed 

 as time permitted. These soils contained almost no 

 vegetable matter when planted, and as clean cultivation 

 is nearly the universal practice, but little has since been 

 added. 



One of the more important actions of decaying vegetable 

 matter is that it tends to prevent clayey soils from be- 

 coming hard or puddled. It is a noticeable fact that 

 toward the middle or latter part of the season, soil that 

 appeared to be in good tilth in the spring gradually be- 

 comes more and more compact, until finally, in the worst 

 types, it becomes almost impervious to water. Measure- 

 ments taken in such an orchard in August will illustrate 

 this point. Water had been running in the furrows 

 twenty-four hours. Two furrows between each two rows 

 of trees were supposed to be sufficient to irrigate the 

 orchard, allowing the water to run twenty-four hours. 

 Measurements taken just after the water had been turned 

 off showed that the moisture had penetrated to a depth 

 of only eighteen inches, and twenty-eight inches laterally. 

 It is obvious that trees should never be planted in such soil. 



There are a great many acres of such land planted to 

 orchards, and it is safe to say that the most of it will sooner 



