23 



afford to use commercial fertilizers at random. No more can they 

 afford to have their crops fail when a small outlay for the proper 

 fertilizer would bring a bountiful harvest. And it is time that 

 they understood these facts, the reasons, and how to make use of 

 them. 



14. The only way to find out what our soils want is to study 

 them by careful observation and experiments. Success in farming, 

 as in other business, requires the use of brains. 



Soils vary greatly in regard to their needs. Hundreds of ex- 

 periments show that the ingredients most often lacking in soils 

 east of the Mississippi are first phosphate, next nitrogen, and then 

 potash. Iu many cases it is not the lack of any particular article 

 which makes soils infertile, but other circumstances. 



The feeding capacities of plants are most important, but we are 

 deplorably in the dark as to why they differ. Leguminous crops 

 gather nitrogen ; why is it? Clover takes away much more nitro- 

 gen from the soil than wheat ; yet it is much less dependent upon 

 nitrogen in fertilizers, though this is contrary to what theory would 

 lead us to expect. 



The question whether corn can gather its own nitrogen has been 

 much discussed. Experiments bear emphatic testimony on this 

 point. It has failed to respond to nitrogen, — it may respond, but 

 not in proportion to the amount applied, — when it would respond 

 to phosphate and potash. 



The corn plant has shown itself capable of getting on and 

 bringing fair yields with small amounts of the less costly mineral 

 fertilizers, even in the worn-out soils of the Eastern States. With 

 this help it has gathered its nitrogen from natural sources, and 

 holds it readily to be fed out on the farm and returned in the 

 form of manure for other crops. In other words, the experiments 

 thus far imply that corn has, somehow or other, the power to 

 gather a great deal of nitrogen from soil or air, or both ; that in 

 this respect it comes nearer to the legumes than the cereals ; that, 

 in short, corn maybe classed with the "renovating" crops. If 

 this is really so, — and this can be settled only by continued 

 experimenting, — then our great cereal, instead of simply being a 

 consumer of the fertility of our soils, may be used as an agent for 

 their restoration. 



Four-fifths of the weight of the air around us is nitrogen; and 

 the question comes up, Can plants — can any plants — avail them- 

 selves of it? Boussingault and Lawes concluded that the}' could 

 not, and that we are drawing for our nitrogen on the stores 

 accumulated in the ground in past ages. But there are facts 

 which are hard to explain on this hypothesis, and there is a feel- 



