FERTILIZEES. 



281 



ber tabulated by Professor TV. O. Atwater, by 

 whom, as Director of the Connecticut Agri- 

 cultural Experiment Station, the experiments 

 were suggested, are of no inconsiderable in- 

 terest. 



Experiments for testing the Needs of Soils. 

 Of these experiments the larger number were 

 performed by farmers as a means of learning 

 what ingredients of plant-food were most 

 needed by their soils and crops. The princi- 

 ple upon which they are based is briefly this : 

 The chief office of fertilizers is to supply the 

 plant-food that our crops need and soils fail to 

 furnish. It is not good economy to pay high 

 prices for materials which the soil may be made 

 to yield in abundance or which may be sup- 

 plied by the carefully husbanded manures of 

 the farm, but it is good economy to supply the 

 Jacking ones in the cheapest way. The most 

 important ingredients of our common commer- 

 cial fertilizers are phosphoric acid, nitrogen, 

 and potash, because of both their scarcity in 

 the soil and their high cost. It is in furnish- 

 ing these that guano, phosphates, bone-ma- 

 nures, potash salts, fertilizers for special crops, 

 etc., are chiefly useful. The experiments pro- 

 vided the three ingredients named, each by 

 itself, two by two, and all three together. Ni- 

 trogen was supplied in nitrate of soda, phos- 

 phoric acid in dissolved bone-black, and pot- 

 ash in the German muriate. Muriate of potash, 

 at the rate of 150 pounds per acre, increased 

 the yield of corn in some cases from scarcely 

 enough to be worth husking to over sixty bush- 

 els of shelled corn with a rich growth of stalks, 

 while in other places it was without marked 

 effect, and alone it was not usually profitable. 

 "With superphosphate numerous experimenters 

 compute their gain at $20 to $40 per acre, 

 while others find large loss. With each of the 

 other materials and mixtures the same is true 

 to a greater or less degree. On the average 

 the complete chemical fertilizer has brought 

 larger, better, and surer crops than farm ma- 

 nures. The experiments show conclusively 

 that: 



1. Soils vary widely in their capacities for 

 supplying crops with food, and consequently 

 in their demand for fertilizers. 



2. The right materials, in proper forms and 

 in combinations suited to soil, crop, and sur- 

 roundings, bring large profits. 



3. The way, and the only way, to find what 

 a soil wants is to study it by careful observa- 

 tion and experiments. 



An outcome of these experiments has been 

 the developing of a series of more complicated 

 "special experiments," whose object is the 

 study of certain important problems of fertili- 

 zation and plant-growth. 



The Feeding Capacities of Plants: the Ni- 

 trogen Supply. A vast deal of experience in 

 the laboratory and in the field bears concurrent 

 testimony to the fact (though we are still de- 

 plorably in the dark as to how or why it is so) 

 that different kinds of plants have different 



capacities for making use of the stores of food 

 that soil and air contain. Of the ingredients 

 of plant-food commonly lacking in our soils, 

 the most important, because the most rare and 

 costly, is nitrogen. Leguminous crops, like 

 clover, do somehow or other gather a good 

 supply of nitrogen where cereals, such as 

 wheat, barley, etc., would half starve for. lack 

 of it, and this in the face of the fact that le- 

 guminous plants contain a great deal of ni- 

 trogen and cereals relatively little. Hence a 

 heavy nitrogenous manuring may be profitable 

 for wheat and be in large part lost on clover. 

 To get some more definite information as to 

 the relation of our more common cultivated 

 plants to the nitrogen supply, a " special nitro- 

 gen experiment" was devised, in which were 

 compared the effects of mineral fertilizers (su- 

 perphosphate and potash salt) alone and the 

 same with nitrogen in different amounts and 

 forms. The nitrogen was supplied as nitric 

 acid in nitrate of soda, as ammonia in sulphate 

 of ammonia, as organic nitrogen in dried blood, 

 and the three forms combined. 



Experiments with Corn. The relation of corn 

 to the nitrogen supply has been widely dis- 

 cussed. The main question is whether it is, 

 like wheat, an "exhausting," or like clover, a 

 renovating, crop. Botanically it is closely al- 

 lied to wheat, and the most eminent authori- 

 ties have attributed to it a similar relation as 

 regards its demand for nitrogenous manures. 

 Indeed, " corn manures " with large and very 

 costly quantities of nitrogen have been widely 

 recommended and largely used. So eminent 

 an authority as Dr. Lawes, the famous English 

 experimenter, recommends as "the best possi- 

 ble manure for cereals," including maize, "a 

 mixture of nitrate of soda and superphosphate, 

 while Professors Ville, of France, and Stock- 

 bridge, of the Massachusetts Agricultural Col- 

 lege, whose formulas are widely known and 

 used, have advised the following formulas for 

 corn : 



VILLE FORMULA FOR ONE ACRE. 



STOCKBRIDGE FORMULA FOR ONE ACRE. 



