THE WATER REQUIREMENTS OF FRUIT PLANTS 



15 



certain fruits in comparison with those of certain other plants, are par- 

 ticularly interesting in this connection. 



Table 11. 



-Minimum Water Requirements of the Apricot in Different Soils' 

 (Records made in early September) 



Locality 



Condition of 

 trees 



Moisture in 4 feet of soil (per cent.) 



Total 



Hygro- 

 scopic 



Free 



Tons of free 



water per 



acre 



Dark loam Sisquoc Valley . 



Loan 



Loam 



Loam 



Loam 



Loam 



Black clay. . . . 

 Gravelly loam 



East of Ventura (shallow 

 cultivation) 



Ventura (shallow culti- 

 vation) 



Ventura (deep cultivation) 



Los Berrios Hill 



Experiment station 



Niles (no cultivation) 



Niles (cultivation 3 inches) 



Niles (cultivation 6 inches) 



Woodland 



Woodland 



Sand East of Davisville 



Alluvial Davisville 



112 

 304 

 72 

 88 

 

 168 

 240 

 736 

 152 

 96 

 168 



In commenting upon these tables Loughridge states: "The apricot, olive 

 and peach do well on less water than other orchard fruits, 1 per cent, of free 

 water being sufficient if constantly present. With this amount the citrus fruits, 

 pears and plums were found to suffer, though the citrus fruits were in good con- 

 dition with a little more water. The almond seems to require about twice the 

 water that the apricot does, while the prune was found to suffer with three times 

 the water in which the apricot was flourishing. 



" Emphasis should be placed on the fact that this free water should be present 

 throughout the soil to the depth of 4 feet at least and especially around the 

 feeding rootlets of the tree. The surface of the soil may be wet, and yet the 

 tree may suffer if the ground below be so dry that the rootlets are not able to 

 draw sufficient moisture. This drying-out of the under-soil is one of the evil 

 effects of a severely dry season, and unless the rainfall of the succeeding winter be 

 sufficient to penetrate to the depth of several feet and moisten the soil around 

 the rootlets the trees will suffer almost as if no rain had fallen. The same is 

 true with regard to irrigation ; those who have to resort to the artificial application 

 of water to their lands because of insufficient rainfall, should so apply it that it 

 may reach the tree rootlets at the depth of several feet below the surface. This 

 is too often not done, and examination will show that the water has, even after 

 2 days' irrigation with running water in furrows, not soaked down more than 10 

 or 12 inches, if that much."^^ 



At first, it may seem that the field observations of Loughridge are 

 not in agreement with the conclusion of Briggs and Shantz that the 

 wilting coefficients are practically the same for all plants growing in the 



