66 FERTILITY AND FERTILIZER HINTS 



nitrogen into nitrates. A wet season checks nitrification and 

 hence nitrate of soda and sulphate of ammonia should give better 

 results than the organic materials. 



For Soils Well Supplied and Long Growing Crops. — Should the 

 soil have a sufficient natural supply of organic nitrogen as from 

 some leguminous crop plowed under, etc., perhaps no organic 

 nitrogenous material should be applied and a small application 

 of some one of the mineral salts may suffice to give the crop a 

 start. If the crop is a long growing one, an organic product 

 may prove best, as it gives up its nitrogen in smaller amounts and 

 more slowly than the chemicals and will thus stay with the crop 

 the whole season. Mixtures of minerals and organic materials 

 may sometimes be best so as to enable the plant to get a quick 

 start by supplying immediate food and when this supply is ex- 

 hausted, to furnish nourishment from the organic sources for 

 'the remainder of the season. The fertilizer manufacturers often 

 use two or three dififerent nitrogenous substances of different 

 forms, as nitrate of soda, sulphate of ammonia and cotton-seed 

 meal, in their fertilizers to allow the plant a continual supply 

 of available nitrogen. Mixtures of organic materials of different 

 availabilities may make excellent combinations for certain crops. 



For Large Crops and Building up the Soil. — Should a large crop 

 be desired the chemicals and the active organic substances would 

 perhaps be preferable, but should the building up of the soil for 

 some future crop be wished, the less active organic materials 

 would prove more valuable than nitrate of soda, ammonium sul- 

 phate, lime nitrate, calcium cyanamid, dried blood, cotton-seed 

 meal, etc., as these materials are all changed to the nitrate form, 

 except nitrate of soda which is already in this form, either im- 

 mediately or during the season and would in all probability be 

 lost because nitrates do not become fixed in the soil and are readi- 

 ly washed away by heavy rains. The nitrogen in organic ma- 

 terials is not soluble in water to any great extent as is the case 

 with nitrate of soda, sulphate of ammonia, lime nitrate and cal- 

 cium cyanamid so that the losses by leaching of the former sub- 

 stances are not considerable as compared to those of the latter. 



It is evident then that the farmer should select those sub- 



