CHEMISTRY OF THE GARDEN. 31 



In general, the method of maintaining fertility of soils 

 is by the application of stable or barnyard manure, which 

 may be termed the king of manures, as it can be pro- 

 duced upon every farm, and contains, when good, all 

 the ingredients needed to make a complete and assimila- 

 ble manure. Most prominent among these ingredients 

 are nitrogen compounds, phosphate of lime, potash and 

 lime. All soils, however, do not need the addition of 

 all four agents ; nitrogenous fertilizers are often not 

 needed for peas, beans and clover, leguminous crops. 

 The nitrogenized matter, on the other hand, is often 

 applied to wheat, barley, oats, beets, turnips, and it may 

 be said to be necessary to every crop. 



The potash, the active principle of wood ashes, is a 

 suitable fertilizer for peas, beans, clover, flax and pota- 

 toes. The phosphate of lime is largely drawn upon by 

 corn, turnip and radish. The chief supply, in a com- 

 mercial way, is from bones which contain phosphate 

 of lime, carbonate of lime, a little gelatine, albumen 

 and oil. 



The lime, ordinarily in the form of carbonate or 

 sulphate, is not so pronounced in its effects, but lime 

 must always be present to produce the best results. The 

 question may occur, where can these concentrated ingre- 

 dients for the manufacture of a complete manure be 

 obtained ; and we meet the query by saying, assimilable 

 nitrogen may be had, to the extent of twenty per cent. , 

 in sulphate of ammonia, fifteen per cent, in nitrate of 

 soda, fourteen per cent, in nitrate of potassa, or in dried 

 blood or flesh from slaughter houses or fish factories. 

 These nitrates, preferably that of potassa, are best for 

 vegetables, especially root crops ; the sulphates for the 

 cereals. Phosphate of lime can be had, to the extent of 

 fifty per cent., in bone dust, seventy per cent, in bone 

 ashes and bone black, and in superphosphate of lime, 

 which is phosphate of lime treated with sulphuric acid, 



