720 AGRICULTURE 



as lying at the very foundation of agriculture and demanding the 

 most careful consideration because the conditions of life in the civil- 

 ized quarters of the globe were thought to cause a constant loss 

 of nitrogen. Every collection of animals, brute and human, was 

 destroying the combined nitrogen-supply; every town and city was 

 dissipating enormous quantities of it through its sewers and into 

 the atmosphere. Tons of this valuable element were being burned in 

 explosives, and nitrates enough to grow bread for a whole city were 

 being destroyed in single battles. At one time there were many 

 who, like Sir William Crookes, predicted a nitrogen famine in the 

 soil which in time would lead to a bread famine throughout the 

 world. 



One does not have to read far in the agricultural literature of to-day 

 before finding that all these ideas have been entirely changed. The 

 soil is now known to be filled so completely with living things as to 

 entitle it to be considered a vital mass itself, and even those ele- 

 ments in it not endowed with life now have the highest significance 

 as the necessary environment of the living organisms which they 

 help to nourish. We know that there are countless organisms in the 

 soil, rendering many different kinds of service in preparing it to be the 

 home of the plants, and, what is more important, in preparing the food 

 for the plants themselves. Some of these organisms dissolve the 

 mineral matter of the soils, others exert their activity on the organic 

 nitrogen in the humus of the soil; others develop parasitically or 

 symbiotically with growing plants, like the legumes, herding in 

 colonies upon their roots and securing by their vitality, in a way we 

 do not fully understand, the oxidation of the free nitrogen of the 

 atmosphere. Still others have the ability, independently, apparently 

 without the aid of plant vitality, either to secure the oxidation of 

 atmospheric nitrogen or to produce ammonia. Investigations along 

 these lines, which have now led to the systematic distribution of 

 nitrogen-fixing bacteria for inoculating the soil, have, for a time at 

 least, dispelled all dreams of early famines, and have given the world 

 an assurance of a sufficiency of bread for at least an indefinite period. 

 The refined scientific investigations of Nobbe in Germany have now 

 been made practically effective in fixing nitrogen in the soil. Soil 

 or seed can now be inoculated with the nitrogen-fixing bacteria 

 just as dough is inoculated with yeast. 



Mention might also be made in this connection of the proposals to 

 combine the nitrogen and oxygen of the atmosphere by the electric 

 spark, as is now being actually attempted at Niagara. Definite 

 reports of results are not yet obtainable, but if this can be done on 

 a large scale, we shall be able to utilize the great water-powers to 

 make this valuable food for plants from the inexhaustible stores 

 of the atmosphere. 



