CALIFORNIA FRUITS: HOW TO GROW THEM 



PHOSPHATIC MATERIALS 

 phosphate iS& i 



Phosphatic meal Acid phosphate Dissolved bone 



Raw ground bone Double acid phosphate Apatite 



Bone black 



POTASH MATERIALS 



Potassium chloride Cement plant potash Kelp ash 



Potassium carbonate Blast furnace potash 5 1 ried ke ^P 



Kainite Potassium sulphate Plant ash 



Kieserite Potassium nitrate Brine residues 



Potassium-Magnesium Double manure salts Leucite or other potash 



sulphate Carnallite minerals containing at 



Kelp Char Potassium least 20% potassium 



Wood ashes Magnesium carbonate oxide 

 Manure ash 



SULPHUR MATERIALS 



Flowers of sulphur. Magnesium sulphate Any of the sulphates men- 

 Calcium sulphate Sulphide minerals tioned in the other lists 

 Sodium sulphate 



CALCIUM MATERIALS 



Calcium oxide (quick Calcium hydrate (water -Calcium carbonate (ground 

 lime) slaked lime) limestone or air slaked 



lime) 



SOLUBLE CALCIUM MATERIALS 

 Gypsum Calcium nitrate Calcium cyanamide 



ORGANIC MATERIALS 



Barnyard manure Legume straws Goat manure 



Cow manure Horse manure Green plant tissue 



Sheep manure Hog manure Sewage sludge 

 Poultry manure 



It may transpire through present and future investigations that 

 the carriers of other elements than those considered may have to be 

 properly included among fertilizer materials whether those elements 

 be essential to plant growth or not, but thus far, there seems to be 

 no warrant for going farther than as enumerated above. At the 

 same time, the limitations drawn above will rule out such fake 

 materials as bacterized peat, dried peat, solutions carrying fertilizer 

 elements, cultures, etc. 



THE VARIABILITY OF SOILS 



Recent studies at the California Agricultural Experiment Station 

 have shown that we must modify to a great extent our ideas relative 

 to all matters pertaining to soils because of the high degree of 

 variability of the latter. Everybody recognizes that, in a given 

 field, soils may show considerable variability, which is evident to 

 the eye and touch of the inexperienced. Few people appreciate to- 

 day, however, that even in a soil which seems entirely uniform there 

 may exist an enormous variability in the smallest distances. Such 

 variability may concern the physical properties of a soil such as 

 moisture-holding power, just as much as the soil's content of the 



