144 CALIFORNIA FRUITS I HOW TO GROW THEM 



Ashes from wood fires are the most available source of potash, but it 

 is a mistake to regard wood ashes as valuable only for their potash 

 contents. Professor Storer has found by analysis of a number of 

 samples of house ashes, that selected samples contain 8^2 per cent of 

 real potash, and 2 per cent of phosphoric acid, or say 4 l / 2 pounds of 

 potash and one pound of phosphoric per bushel. Hence there is 

 enough potash and phosphoric acid to make a bushel of ashes worth 

 twenty or twenty-five cents, and besides that, some ten or fifteen cents 

 additional may not be allowed for the "alkali power" of the ashes, i. e., 

 the force of alkalinity which enables ashes to rot weeds and to ferment 

 peat. 



These facts suggest to the fruit grower that he should carefully 

 preserve all home-made wood ashes and apply them to the soil at once, 

 or, if stored for future application, be sure that they are kept dry. 

 Leached ashes from the lye barrel, or ashes from open piles, leached 

 by rains, are hardly worth handling. Coal ashes are almost devoid 

 of fertilizing properties, though, if finely divided, as in the case of 

 coals burning completely, their use is beneficial, mechanically, on clay 

 soils, in the same way that fine sand would be. 



The chief supplies of potash salts are now brought from Germany, 

 but a strenuous effort is being made to develop a local supply from 

 sea-weeds and by developing deposits in the arid regions of this 

 country. 



NITROGEN 



Nitrogen ministers directly to the vegetative activity of the plant 

 and this is a wonderful stimulant of wood growth and foliage. Sup- 

 plies of this substance can be had from animal manures, which will 

 be considered later. The effect of stable manure upon the soil and 

 the plant is notably strengthening and restorative. For this reason 

 money and effort are often well -expended in securing it even beyond 

 the cost of the equivalent of the plant food which it contains. Another 

 natural form of nitrogen in cover crops or green manures will be 

 discussed presently. Of commercial forms of nitrogen, tankage and 

 dried blood are highly esteemed for orchard use, and there is large 

 use also of Chile saltpeter, which contains about sixteen per cent of 

 nitrogen, in immediately available form. From two to four hundred 

 pounds per acre is the usual application, and it should be evenly dis- 

 tributed over the ground, not collected near the trees. Sulphate of 

 ammonia is another available source of nitrogen obtainable in com- 

 merce; a good commercial article contains twenty per cent and over 

 of nitrogen. It does not, however, act quite as rapidly as the Chile 

 saltpeter. A suggestion of caution in the use of nitrogenous manures 

 will be given presently. 



LIME, GYPSUM AND MARL 



Lime is another substance usually abundant in California soils, 

 but still often desirable as an application. This is, notably, the case 

 on our heavy clays or adobes, where, as has already been mentioned 



