Manures and Fertilizers 



content of these in our soil, together with the knowledge we have as to their use, 

 measures, in a sense, our prosperity as an agricultural people, the possibilities of losing 

 them from the soil is a matter of national concern, and is of vital interest to individual 

 farmers, who, in the aggregate, make up that part of the nation directly affected by the 

 results of such loss. It would, perhaps, be possible, by a careful chemical survey of our 

 soils, to determine both the actual and potential fertility of our entire country, and this 

 knowledge, together with an accurate measure of the intelligence exercised in its use, 

 would enable a prediction as to our future development, if present methods were con- 

 tinued. That is, whether our land would become barren and worthless, as has been 

 the case in many older countries which at one time were quite as productive, or whether 

 it would constantly increase in productiveness, even with continuous and profitable 

 cropping." 



As before stated, the principal elements necessary for plant growth are 

 nitrogen, phosphoric acid and potash. Nitrogen, which is one of the most 

 useful and most essential of the elements of plant food, is the most volatile of 

 all these elements, the easiest lost and the most expensive to replace. It is 

 not only taken up and removed from the soil by the crop, but where soils are 

 allowed to remain uncropped, a large percentage of the nitrogen contained 

 therein is lost by drainage ; this loss, however, is practically prevented in 

 soils which are continuously cropped. There is also a very large loss by 

 evaporation, especially where certain classes of crops are grown upon lands 

 that are especially rich in nitrogen. Experiments have shown that upon the 

 very rich prairie lands of the West, where continuous crops of wheat are 

 grown, the natural loss of nitrogen by evaporation is much greater than the 

 quantity removed by the crop, the average crop of wheat removing about 

 241/2 pounds of nitrogen per acre, while 146 pounds per acre are lost by 

 evaporation. On the contrary, where crops were grown in rotation with 

 clover or some other nitrogenous-gathering plant, the gain in nitrogen ex- 

 ceeded the amount carried away by the crop, and under such culture, as there 

 was no loss by drainage, the land so cropped gradually increased its store of 

 nitrogen and its fertility was not impaired. 



The late Professor Kedzie, of the Agricultural College of Michigan, 

 strongly recommended the use of nitrogenous gathering plants for the purpose 

 of permanently maintaining the fertility of land. In the production of crops, 

 he also recommended abundant applications of nitrogenous manures until the 

 growth of the plant is perfected, at which period liberal applications of 

 super-phosphate or phosphoric acid result in the production of abundant 

 crops. He gave as an example a pear orchard which had made a remarkable 

 growth of foliage and tree for a number of years, but had borne no fruit. A 

 liberal application of super-phosphate had produced an enormous crop of 

 fruit, and this same orchard was maintained in profitable productive con- 



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