Chapter IX. 



RELATIONS OF CROPS TO MANURES, FERTILIZERS, AND 

 ROTATION. 



The preceding section having shown how easily all the valuable 

 nitrates are dissolved and washed away by rain and how completely 

 the permanent fertility of a field depends upon microbic action 

 within the soil, and especially wdien attached to leguminous plants, 

 we shall therefore not be surprised to learn that expensive and arti- 

 ficial chemical fertilizers and guanos are often less important than 

 the enrichment that comes more naturally by the rotation of crops. 



ARTIFICIAL FERTILIZERS AND MANURES. 



As the result of tw^elve years' experience, J. W. Sanborn, of Mis- 

 souri, states that although both science and practice assert the efficacy 

 of artificial fertilizers, yet their profitahle use is a matter of grave 

 concern both in the granite soil of New England and in the richer 

 soil of the Mississippi Valley. His general conclusions are that we 

 do not need to use as much nitrogen in this climate as in Europe, 

 especially as in England, nor as much as has generally been consid- 

 ered necessary; that enriching by rotation of crops is the preferable 

 method; that nitrogen (viz, fertilizers) may be profitably bought 

 only for a few winter or early and narrow-leaved plants, but, as 

 a general truth, broad-leaved plants and those maturing in late sum- 

 mer and in the fall do not require addition of nitrogen to the soil. 

 (Agr. Sci., Vol. I. p. 227.) 



From the extensive experiments with fertilizers made at the Ohio 

 Agricultural Experiment Station the following results have been 

 secured, based on both station work and that done by cooperating 

 farmers throughout the State: 



Maize. — On soils capable of producing 50 bushels of shelled corn to 

 the acre no artificial fertilizer is likely to produce an increase of 

 crop sufficient to pay the cost. On soils deficient in fertility, phos- 

 phoric acid may be used with profit. 



Wheat. — As a rule no more wheat has been harvested from plats 

 treated with commercial fertilizers than from those receiving no 

 fertilizers, whereas farm manures produced a marked increase. At 

 the present prices of grain and fertilizers the increase of crops will 

 not cover the cost of the fertilizer. 



Oats. — Plats receiving nitrates showed a marked superiority in the 

 growing season, but lodged badly before harvest. Muriate of potash 

 gave an insignificant increase. (Agr. Sci., Vol. IV, p. 237.) 



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