126 FOOD FOR PLANTS 



Fish Meal (average) S%7f Nitrogen, V/c available Phosphoric Acid. 

 Recovery of Nitrogen by crop, 38^%. 



Tankage and "Brand" or Mixed Fertilizers are taken up later. 



The average Nitrogen recovery by crop is 38%7c in tankage. 



The average Nitrogen recovery by crop is 40% to 507o in mixtures, 

 according to the sources of Nitrogen. 



Nitrate of Soda. 



It is not necessary to use Potash with Nitrate of 

 Soda in California, as it is a proven and accepted fact 

 that Soda releases unavailable Potash from the soil. 

 California soils average extremely high in Potash 

 and low in Soda, hence applications of Nitrate of 

 Soda are generally beneficial in balancing the bases 

 and making available Potash — thus supplying a 

 necessary plant food. In 400 pounds of Nitrate of 

 Soda there is 146 pounds of Soda. The average crop 

 requires from 40 to 100 pounds of Soda and 60 pounds 

 will be required and dispelled in releasing Potash. 



For example, refer to R. R. Snowden's work dated 

 October, 1923, wherein he quotes the University of 

 California as follows: "According to California 

 Bulletin No. 93, page 37, a crop of 12,800 pounds of 

 Oranges per acre, equivalent to about 2 boxes per 

 tree, will take out 46.7 pounds of Soda. Ninety-two 

 pounds of Potash required by this crop will require 

 60.5 pounds of Soda to release it from the silicates, 

 whereby this amount of Soda becomes practically 

 insoluble. Then, according to the same authority, 

 the tree body and leaves contain a larger percentage 

 of Soda in the ash and more ash than the fruit does. 

 According to this estimate, there can be no possible 

 sodium residue." 



Through the use of Nitrate of Soda the eifect of 

 over-nitration is practically impossible, as the Soda 



