The Bulletin. 73 



either of the two lorins meutiouod ahore is used. When the application is 

 made in the fall, time is afforded for the lime to become well mixed with 

 the soil before spriiis?, especially so if it is put in properly. The carbonate or 

 air-slaked form of lime does not act as energetically as do the quick and 

 water-slaked forms, 



HOW APPLY AND AMOUNT. 



As a general rule, lime >should be applied broadcast and then thoroughly 

 harrowed and disked into the soil. Of slaked lime the quantity required per 

 acre varies quite considerably with different soils, crops, and conditions. 

 Usually, however, the amount necessary to use will vary between 1,000 and 

 3,000 pounds, or its equivalent of some other form, per acre. Never mix 

 lime, especially in the caustic or water-slaked forms, with any material con- 

 taining ammonia, before applying it to the soil, because the lime would tend 

 to set free into the atmosphere some of the ammonia, and hence it would be 

 lost. For this reason it is exceedingly unwise to mix lime directly with 

 stable manure. Do not add lime to acid phosphate or to mixtures containing 

 this material, for such a procedure would result in some or all of the avail- 

 able phosphoric acid of the acid phosphate being changed to a less soluble or 

 available form, the amount changed being governed largely by the proportion 

 of lime to acid phosphate in the mixture and by the mechanical condition of 

 the mixture. 



When lime is added to permanent pastures and meadows it should be applied 

 broadcast in the fall or early winter and left on the surface. For this pur- 

 pose the carbonate form will usually be found best suited. 



FOEMS OF LIME AND THEIR EQUIVALENTS. 



There are three chemical forms of lime used commercially other than 

 gypsum (land plaster) or sulphate of lime. Each of these forms is known 

 by a goodly number of names. The forms and synonymous names are as fol- 

 lows : 



(1) Caustic, quick, burnt, builders', rock, stone, or unslaked lime. 



(2) Carbonate, agricultural, marble, limestone, marl, chalk, calcite, or air- 

 slaked. 



(3) Water-slaked or hydrated lime. 



As all three of these forms of lime are suited for agricultural purposes, it 

 becomes important in purchasing to know the relative equivalents in actual 

 lime (calcium oxide). When 178 pounds of a good grade of carbonate of 

 lime is burnt in the kiln about 100 pounds of quick or caustic lime is secured ; 

 the remaining 78 pounds of the original substance is driven off into the atmos- 

 phere as carbon dioxide or carbonate acid gas. If the above 100 pounds of 

 quicklime, secured by burning, is exposed to the atmosphere for some time, 

 it will absorb carbon dioxide again from the air, and will, when fully sat- 

 urated with it, weigh 178 pounds. If 5G pounds of the burnt lime is water- 

 slaked with just enough water to complete the chemical change, the resulting 

 hydrated or water-slaked lime will weigh about 74 pounds. In other words, 

 100 pounds of quicklime will take up in chemical combination about 32 pounds 

 of water, thereby increasing its weight about one-third by water-slaking. 



From the above it may be seen that the most concentrated form of lime is 

 the caustic or burnt lime. This being so, where the lime has to be freighted 

 long distances on the railroad or hauled several miles on country roads, or 

 both, it will usually be found that this will be a cheaper form in which to 

 buy lime, but not always. For instance, the freight on a car-load of carbon- 

 ate of lime (agricultural lime, so called) will be the same as that on the same 

 amount of quick or burnt lime, yet there would be almost twice as much 

 actual lime (calcium oxide) in the latter as in the former; hence the freight 

 on the lime contained in the quick form would be only about one-half of what 

 the actual lime contained in the carbonate form costs per ton. 



In securing quotations on lime, do so upon percentage composition of calcium 

 oxide and upon delivery at your nearest railroad station. If they are secured 

 in this way it will not be difficult to decide from whom to purchase. If these 

 precautions are not observed it will not always be easy to decide which will 



