24G STATE BOAKD OF AGRICULTURE. 



the crop iicoils in inamiro is iiitro2:cii. To be sure four-fifths of tlie air is ni- 

 tro<j;en, l)uL it is in the gaseous form, and cannot be taken up by the phuit. 

 To be usL'ful, it must bo in the form of nitric acid, nitrates, ammonia, or 

 in some otiier form of combination. The amount of these materials in 

 the air and soil is very small, and they are very beneOcial when ap- 

 plied to crops. The largest part of every plant comes from the atmos- 

 l)herc. Eighty per cent of every load of hay, and eighty-four per cent 

 of every bushel of wheat are made up of materials derived from the uir. So 

 much for tlie organic elenicnts. Now turning to tlie ash elements, we find 

 sand, lime, magnesia, suli)huric acid and chlorine and iron. These are all 

 present in soil in snllicient amount for crops. What then of the asli elements 

 do soils lack that we need to supply? They want phosphoric acid and potash. 

 But little phosphoric acid is prc'^ent in soils, at the most not more than two- 

 llfths of one per cent. It is combined with lime and magnesia as phosphate 

 of lime and magnesia, and is very insoluble, being taken up by the plant 

 very slowly. Potash is locked up in soil, iu the form of the silicate of potash, 

 and is exceedingly insoluble. 



So it appears that all the materials needed in a manure are potash, phos- 

 phoric acid and nitrogen in a form that will dissolve readily iu water, and so 

 can be used at once by the plant. 



Now, all this may seem pretty dry and perhaps difficult to understand. But 

 the farmer of to-day who would be up with the times must understand some- 

 thing of the composition of soils, of the food his crops require, and what ma- 

 nures it is best to apply. I apprehend that many thousands of dollars have 

 been wasted in fertilizers through not knowing what elements are needed for 

 crops. The farmer should be a reading, thinking man. There must be a 

 thorough mixture of brains in farming to achieve the highest success. 



The foundation for the application of all fertilizers lies in a very thorough 

 understanding of the composition of plants, and that knowledge we have. 

 Many hundreds of analyses of agricultural plants have been published, and we 

 know approximately how many pounds of the different elements any croii will 

 take from the soil. What elements are necessary to enable plants to grow and 

 produce seed was determined by German and French chemists by the method 

 of "water culture," as it is called, in which the seeds of plants were sprouted 

 in moist cotton and then put in jars containing water in which were dissolved 

 all the elements except the one which they wished to determine whether it was 

 essential to the growth of the plant or not. In this way it was found that when 

 potash was not present the plants grew only a few inches in height, Avere feeble 

 and sickly and soon died. In the absence of nitrates or ammonia plants failed 

 to mature, and when phosphates were absent no seed was formed. There are a 

 few other elements, such as sulphuric acid and chlorine that are needed for 

 plants to grow, but they are usually present in the soil in sufficient amount for 

 all crops. 



Supposing we wish to buy potash, nitrogen and phosphoric acid for fertiliz- 

 ing purposes, in what form can they be obtained in the market? Of potash 

 there are the crude salts that come from Germany njostly, such as the muriate 

 and sulphate of potash. The latter is the cheaper, its cheapest form selling 

 for $25 a ton. The nitrate of potash may be used, but this is more expensive 

 than the others. 



Of nitrogenous manures there is guano, containing from 11 to 13 per cent 

 of ammonia, at IGO a ton, or fish scrap, or "dried blood" from slaughter 

 houses. If phosphoric acid is desired, it may be bought in the form of ground 



