296 LEGUMES AND FERTILIZERS 



of lime. The continuous liming without the use of manure, will 

 therefore deplete the soil. 



" Lime and lime without manure 

 Makes both farm and farmer poor." 



6. Nearly all kinds of beneficial bacteria in soils will thrive 

 better in the presence of lime. This is notably true of the bacteria 

 which aid legumes in obtaining nitrogen from the air. 



7. Lime undoubtedly serves as a direct plant food for some 

 legumes. This is most notable in the growth of alfalfa. Analysis 

 shows that this plant contains considerable lime in its ash. 



Forms of Lime. — There are several forms of lime used for gar- 

 dens, orchards, and fields. These differ in their action, perma- 

 nence, cost, etc. (Fig. 206). 



Ground limestone is one of the best forms to use. In regions 

 where it can be obtained it is cheaper than other forms of lime. 

 Its action is not so rapid as the burned lime, but it is more lasting 

 in its effects. It should be ground very fine and may be applied at 

 the rate of one, two, or more tons per acre without any fear of 

 injury to soil or crop. 



' Freshly burned lime is very caustic in its action. It burns out the 

 organic matter from soils very quickly and has a very pronounced 

 effect in aiding growth of clover, alfalfa, etc. Its effects are 

 not so lasting as other forms of lime. It should be used in quanti- 

 ties ranging from one-fourth or one-half ton per acre upward. 

 Before spreading, it is usually put in a pile to air-slake. Some 

 water may be added to help start the action. After it is in the form 

 of fine powder it may be spread. It nearly doubles in bulk and 

 weight during the process of air -slaking. 



Hydrated lime is about the same in its action as the air-slaked 

 lime already described. It is the by-product of dealers and kilns 

 where fresh lime is sold. It is sold either in bulk or in bags, and is in 

 the form of fine powder. It usually becomes rather old and takes 

 up more moisture than the freshly slaked lime. The cost is often 

 out of proportion to its value as compared with other forms of lime. 



Ground oyster shell is similar in action to ground limestone and 

 may be used at the same rates. The price may be low enough to 

 warrant its use in regions near its source. 



Hard-wood ashes contain, when not leached, thirty to thirty-five 

 per cent of lime besides three to eight per cent of potash. When 

 obtainable they should be used on gardens, about the bush fruits, 

 and in orchards. 



