162 EXPERIMENTAL FARMS. 



The alkaline qualities of lime and marl give these substances a special value for 

 neutralizing the acidity and altering certain injurious iron compounds existing in many 

 marshy and low lands. Such soils are frequently also lacking in lime. 



Lime and marl improve the tilth of heavy clays, flocculating the soil ; this renders 

 it permeable to air and destroys plasticity. 



While the application of an excess of lime is very apt to do harm and to eventually 

 exhaust a soil's fertility (unless care is taken to replace the plant food withdrawn by 

 the crops), no injury can result from an over application of marl. The latter .supplies 

 lime in a mildly alkaline form, peculiarly adapted to the improvement of soils and for 

 the wants of plants. 



AN "EARTHY DEPOSIT » 



FROM THE NORTH-WEST TERRITORIES. 



This material was found on Jack-fish Creek, near Battleford, N. W. T. It occurs 

 in " pockets "15 inches to 18 inches below the surface of the soil, which is a gravelly 

 loam. The pockets are reported as being variable in size, though none exceed a few 

 feet in diameter. In appearance it is grayish white and earthy, resembling marl. 

 When received, it was in powder and friable lumps. Locally, the substance has 

 been used for whitewashing and cementing purposes. Its composition was ascertained 

 to be as follows : — 



Analysis. 



Water (dried at 100° C.) 6-78 



Loss on ignition (combined water, organic matter) 3 '51 



Oxide of iron and alumina 1 -64 



Insoluble residue (clay and sand) 9'70 



Sulphate of lime* 24 86 



Carbonate of lime 53"04 



Magnesia 1 -72 



Potash -10 



Soda -10 



Soluble Silica -12 



Phosphoric acid -04 



100-61 



Nitrogen -04 



•Equivalent to 31 "44 per cent gypsum. 



This sample may be considered as consisting essentially of marl (carbonate of 

 lime) and gypsum (sulphate of lime). Of the three more valuable elements of plant 

 food, nitrogen, phosphoric acid and potash, it contains only very small amounts. 



It would prove useful to all soils deficient in lime. (For particulars regarding the 

 agricultural value of carbonate of lime, see under " Marl," page 161.) Gypsum, besides 

 supplying lime, may be regarded as a fertilizer of special value for pease and clover. It 

 is also considered to give good results with turnips, Indian corn and other leafy crops. 



