AIR WATER SOILS. 



923 



Amount of free water required by different crops. 



Free water in 1 

 feet soil. 



rercent- Tons per 

 age. acre. 



Apricots, olive.s, peache.s, soy bean 



Citrus, figs 



Almond.s, plums, saltbusli 



Walnuts, grapes, eucalyptus 



Apples, prunes 



Pears, hairy vetch 



Wheat, corn 



Sugar beets, sorghum 



Cultures suduring. 



Citrus, pears, plums, acacia. 

 Almonds, apples. 

 Barley. 



Prunes. 

 Wheat. 



Sugar beets. 



"The above summary indicates that the apricot, oUve, 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 trees were in good condition 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 ft. 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 tlie ground below be so dry that the rootlets are not able to draw sufficient mois- 

 ture. 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 Sviil aroimd 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 artifi- 

 cial application of water to their lands l)ecause of insufficient rainfall, should so 

 apply it that it may reach the tree rootlets at the depth of several feet below the 

 surface. ' ' 



Alkali and alkali soils, R. H. Loughridge ( Cidifornia Sta. Rpt. 

 ISOS^ pp. 00-117^ Jigs. ^). — A stud}' of the accumulation of alkali in 

 irrig-ated .soils used for the culture of citrus fruits, and the effect of 

 this alkali upon the growth of these fruits, is reported, which showed 

 that after 3 3'ears' use of an artesian water comparatively free from 

 soluble salts (9.46 grains per gallon containing 0.64 grains sodium 

 chlorid and 1.S5 grains sodium carbonate), the soil contained 3,240 

 lbs. of soluble salts per acre to a depth of 3 ft. ; using Lake Elsinore 

 water, containing 98.54 grains per gallon of soluble salts (in which 

 there were 53.62 grains of sodium chlorid and 22.89 grains of sodium 

 carbonate), there was an accumulation in the soil of 15,160 lbs. of 

 alkali per acre, while in unirrigated natural soil there was only about 

 1,250 lbs. In ca.se of the use of the lake water 1,680 lbs. of the alkali 

 accumulated in the soil was sodium carbonate and 6,120 lbs. sodium 

 chlorid; with artesian water there was 640 lbs. of carbonate and 360 

 lbs. of chlorid. The unirrigated soil contained neither of these salts. 



It was observed that the citrus orchards irrigated with the Elsinore 

 water were in bad condition and the station undertook to ascertain 

 whether the injury to the trees was due to the effect of alkali or to 



