THE IMPORTANCE OF NITROGEN TO THE GROWTH OF 



PLANTS,* 



Being a stateinent of a point of view. 

 The problem stated. 



The thesis of this paper is that a Hmiting factor in the growth of 

 crops may be the amount of water-sokible nitrogen occurring in the soil 

 at a critical time in the plant's life history. Further, that in humid 

 climates, the effect in many instances, perhaps in the majority of instances, 

 of the various cultural methods employed to increase the yield of crops 

 is to modify the amount of water-soluble nitrogen in the soil at the time 

 when and at the place where needed by the plant. It is important to 

 observe that I use the indefinite and not the definite article. I shall main- 

 tain that the amount of water-soluble nitrogen is a limiting factor, not 

 necessarily the limiting factor. 



That by a systematic rotation, the yield of crops is increased by 

 reducing diseases and insect enemies there can be no question. If a 

 muck soil lacks potash, crops may be increased by supplying the needed 

 element. What I shall undertake to show, or perhaps better, to suggest, 

 is that on the majority of agricultural soils in the humid climate of 

 Eastern United States the water-soluble nitrogen is likely to be a limiting 

 factor and that the eff'ect of the various successful cultural methods is 

 to increase the water-soluble nitrogen at the critical time in the plant's 

 life history. 



Should this contention be established by this paper or better, by 

 further more careful and far-reaching investigations, it is believed that 

 the results will have special, practical application to the North and South 

 Atlantic States. 



The importance of nitrogen in the grozvth of plants. 



The experiments and observations here reported do not prove the 

 assumptions just made, but it is believed the evidence is of such a nature 

 as to make a thorough investigation of the subject desirable. Some of 

 the queries which I will raise will be for the purpose of suggesting lines 

 of investigation rather than indicating conclusions reached. 



While the writer of this paper has been connected more or less 

 closely with most of the experiments here reported, the data has in every 



* This paper was first presented on October 17 and 24, 1906, to the Agronomy 

 Seminary of the New York State College of Agriculture : an abstract was submitted 

 on November 12, 1906, to the Society for the promotion of Agricultural Science at 

 Baton Rouge and the paper was again read on November 27, 1906, before the Nor- 

 mal Institute for Farmers' Institute Workers, held at the New York Agricultural 

 Experiment Station. 



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