PROCEEDINGS OF THE WINTER MEETING, 



HELD IN LANSING, TUESDAY AND WEDNESDAY, MARCH 26, AND 27, 1889 



This society's winter meeting was held at the dates above given, part of 

 the sessions being in the state capitol, in the hall of the Michigan State 

 Pioneer society, and part at the Michigan Agricnltural college. 



The session of Tnesday morning, President T. T. Lyon in the chair, was 

 opened by Prof. L. R. Taft of the Agricnltural college in a paper upon 



PLANT FOOD. 



"All plant growth is either at the expense of substance previously stored 

 up within the plant, or of various materials obtained from some outside 

 sources, and which are included under the general term of food. 



" While the character of the food furnished to the plants will have much 

 to do in determining their composition, the nature of the plants will be a 

 far more potent factor; and to this, for the most part, do we owe the varia- 

 tion in the water, ash, and volatile matter of plants. A few years ago 

 much stress was laid upon the value of soil analysis, but now this is only 

 considered of value in that it affords, in a general way, information as to 

 the relative proportions and combinations of the elements contained in 

 soil. Aside from the water it contains, the bulk of a plant is composed 

 of materials that are obtained from the air. 



"Althoiigh the air surrounding a plant may be saturated with a watery 

 vapor, the leaves will be incapable of taking it up, even though it fall upon 

 their surface in the form of rain, and it enters only through the roots. 

 The leaves, however, are able to take up from the air such elements as 

 oxygen, carbon ( in the form of carbonic acid gas ) , and perhaj^s nitrogen 

 in the form of carbonate of ammonia. While the leaves are taking up food 

 from the air, the roots are absorbing it from the soil. The supply there 

 obtained is the result of the decomposition of vegetable or animal matter 

 in the soil, or the breaking up of the minerals therein contained; and if in 

 a soluble form, they are taken up by the water and are carried to the roots. 



"The old idea that the root-tips acted as sponges for the absorption of 

 water is no longer accepted. While all parts of the roots possess this 

 power to a greater or less degree, the principal seat of absorption lies in 

 the new roots, and especially in those that are covered with root-hairs. 

 These hairs are delicate, thread-like extensions from the epidermal cells, 



