FOR BETTER CROPS 71 



not so lasting-. Sometimes one can get crushed limestone 

 screenings, much of it as line as sand. Tiiis stuff is used for con- 

 crete work, walks, and ballast, and often may be bought as low 

 as tifty cents per ton or less. When the g^round limestone is not 

 available, and this coarser material is, we advise its use. I*ut 

 on more of it, and eventually every bit of it will become availa- 

 ble. It will last for many years in the soil, giving- out its bene- 

 ficial influence constantly. Many farmers having ledges of 

 limestone upon their land can well afford to grind their own 

 limestone at home; and a machine capable of grinding a little 

 more than a ton an hour and taking in stones 11 x 13 inches in 



A heavy crop of alfalfa 



size costs about $600.00. These machines are very durable and 

 the expense of operating- them quite light. 



Other Forms of Lime— When limestone rock is burned, tlie 

 carbon is driven off, and caustic lime remains. Burned lime has 

 lost about one-half its weiglit, so that a ton of burned lime has 

 as much power to sweeten soils as two tons of unburned or car- 

 bonate of lime. The one difficulty with burned lime is that it 

 has this caustic nature, and is said to destroy part of the humus 

 of the soil. Burned lime is more easily secured, and the freight 

 rates on it are often less than with the ground limestone. From 

 one to two tons per acre of the caustic lime are used. It may be 

 ground very easily after being burned, and then drilled into the 

 soil; or it may be slaked with a little water so that it falls into 



