MANURES. 



25 



a cheap and very useful supply of potash. They are gener- 

 ally sold on a valuation based on the percentage of actual 

 potash they contain. Kainit contains 13 per cent of potash 

 which is more than twice as much as there is in ordinary un- 

 leached wood ashes. From 200 to 600 pounds of kainit is gen- 

 erally applied per acre. 



Lime is found in abundance in most western soils, but 

 burned limestone, whether as freshly slacked or as quick lime, 

 may often be used to advantage in small quantities when large 

 amounts of stable manure have been used upon the land for a 

 number of years. It should not be used alone, because it ex- 

 hausts the soil. 



Land Plaster is a sulphate of lime. It is not a direct 

 fertilizer, and its method of action is not exactly known. It 

 may occasionally be used to advantage for leguminous crops, 

 such as clover, beans, peas, etc., in applications of from 200 to 

 600 pounds per acre spread broadcast. 



There is Little Need for Commercial Fertilizers at present 

 in most of the western states and they should never be used until 

 the home sources of manure have been exhausted, and then they 

 should be used to supplement rather than replace farm manures, 

 and as aids in close cultivation of gardens. They are generally 

 expens-ive, and results from their use here have not been as 

 satisfactory as in the eastern states. Only the more common 

 kinds to be met with here have been mentioned. 



Those who use commercial fertilizers of the better kinds 

 for the first time are very likely to use too much and seriously 

 injure the crops to which they are applied. It is much better 

 to use too little than too much, and to experiment along this 

 line in a small and inexpensive way to begin with. 



Effect of Manure on Crops. — The proportion of the various 

 plant foods used by dirferent crops varies considerably, some 

 using a larger amount of one element and some of another. 

 Their visible effects w^hen in excess are also quite different. 

 Garden plants that are grown especially for their foliage use 

 large quantities of nitrogen and require it in order to be per- 

 fectly healthy, and seed producing plants use large quantities of 

 phosphoric acid and potash. Where nitrogen in a soluble form 

 is very abundant so as to be in excess in the soil it will be 



