SoiLSj Fertilizers and Irrigation 159 



the addition of anything that is injurious but by the quicker using 

 up of plant food which it already contains. Black alkali is very 

 common in California in alkali lands. In lands which show their 

 quality by good cropping, there is no reason to apprehend black 

 alkali nor to use gypsum to prevent its occurrence. The use of 

 gypsum does stimulate the growth of alfalfa and makes its product 

 greater just as you observe in the experience of your neighbors, 

 but the more they use up the land now the less they will have later, 

 unless they resort to regular fertilization to restore what has been 

 exhausted. But even that may be a good business proposition. 



What Gypsum Does. 



/ intend to fertilise alfalfa and should like to know about gypsum. I 

 have heard it stimulates the grozvth temporarily hut in three or four 

 years hurts the land. I have heavy land. 



The functions of gypsum are: (a) to supply lime when the soil 

 lacks it; (b) to make a heavy soil more mellow, and (c) to act upon 

 other soil substances to render them more available for plant food. 

 These are some of the soil aspects of gypsum; it may have plant 

 aspects also. It is too much to say that gypsum hurts the land; 

 it does, however, help the plant to more quickly exhaust its fertility, 

 and in this respect is not like the direct plant foods which comprise ' 

 the true fertilizers — one of which gypsum is not. It might be best 

 for your pocketbook and for the mechanical condition of the soil to 

 use it, but do not think that it is maintaining the fertility of the 

 land (a service which we expect from the true fertilizers) except as 

 it may supply a possible deficiency of lime. 



How Much Gypsum? 



How much per acre, hoiv frequently and zvhat seasotis of the year 

 are the best time to apply gypsum? 



Of gypsum on alkali, we should begin at the rate of one ton 

 to the acre and repeat the application as frequently as necessary to 

 achieve the desired result. If the alkali was quite strong we would 

 use twice as much. Without reference to an alkaline condition in 

 the soil, and to give heavy soil a more friable character, which pro- 

 motes cultivation, aeration, etc., and, therefore, ministers to more 

 successful production, half a ton to the acre can be used, applications 

 to be repeated as conditions seem to warrant it. 



Wood Ashes in the Garden. 



There is available in my neighborhood a free supply of zvood ashes. 

 Can you tell me how best to distribute the same in a garden (flowers and 

 garden truck), and what, if any, treatment is to be given the ashes for 

 the best results. 



Wood ashes long exposed to rain lose most of their valuable 

 contents, and leached ashes are only of small value. If they are 



