366 MAIZE 



chap, made from dolomite or " magnesian " limestone is found 

 VIH ' by experience to be unsuitable for agricultural purposes 

 {Vipond, i). White lime (calcium carbonate or carbonate of 

 lime) is the sort recommended by agricultural chemists. 



328. Preparation of the Lime. — For agricultural purposes 

 lime is usually burned and slaked before using. To slake 

 lime for use in the field, it is heaped and covered with earth to 

 exclude the air ; water is then poured on it ; in a few days it 

 " falls" into a fine powder suitable for spreading on the land. 

 Full advantage of the lime dressing is obtained only if the 

 lime is very fine in texture; if it is still coarse after burning 

 and slaking it should be ground. 



The Pennsylvania Station {Rep. 1902) shows that the con- 

 tinued use of caustic (i.e. burned) lime, tends to exhaust or 

 destroy the fertility of the soil (see also Hopkins, 5 and 6). 

 Both the Pennsylvania and Maryland Stations found that 

 ground limestone gave better results in sustaining the productive 

 capacity of the soil, than burned lime. Hopkins (6) cites 

 results obtained in Germany and Fngland favouring the use 

 of the former as a more profitable and effective form than the 

 latter. 



329. Mctlwd of Applying Lime. — As lime is somewhat 

 soluble and apt to be carried off in the drainage, it is best to 

 apply it after the soil has been partly prepared ; it is then 

 spread broadcast and cultivated into the surface. The amount 

 used should vary according to the texture and chemical com- 

 position of the soil. Haifa ton per acre is often recommended, 

 but on very heavy, sour soils a ton to the acre may not be too 

 much. In the United States up to 4 tons per acre is some- 

 times used for maize, but ordinarily not more than 2 tons 

 {Hunt, 1). The Agricultural Chemist of the Department or 

 College of Agriculture should be consulted as to the amount 

 to be used on any particular soil. 



330. Phosphatie Manures. — Phosphatic manures, such as 

 superphosphate, bone-meal, and basic slag, may have a greater 

 effect on the second crop than on that to which they are ap- 

 plied. Where they are used on sandy soils a greater yield of 

 maize may be obtained after a crop like cowpeas than would 

 be got in two years where maize is grown continuously 

 without fertilizer ( Watt, R. D., 2). The experiments at the 



