16 BOARD OF AGRICULTURE. 



sufficient quantities in Massachusetts soils for all the wants 

 of plants. 



Now, the different species of plants require these important 

 elements in quite different degrees or quantities : that is, one 

 kind of plant will require nitrogen in large quantities ; 

 another, phosphoric acid; another, potash; and it will be 

 found that almost all cultivated plants will require one or 

 the other of these three things largely in excess of the other 

 two. 



Now, if it is true that the crop to be grown will in quan- 

 tity and quality, to a large extent, depend upon the adapta- 

 tion of the manure to the particular variety of plant, as well 

 as on the quantity applied to the land, it will be proper to 

 inquire how a farmer, with his limited amount of knowledge 

 of the wants of plants, would be able to make the most 

 judicious combination of manure to grow the various species 

 of plants. 



Shall he avail himself of the knowledge acquired by emi- 

 nent chemists who have made researches as to the plant>food 

 required b}^ most plants by repeated analyses of what the 

 whole plant contains ? In answer, I should say. Yes. 



What can the chemist tell us about plants? Why, he can 

 tell us nearly this, — how much nitrogen, how much phos- 

 phoric acid, how much potash, a crop of so many bushels to 

 the acre — with its stalks, leaves, and roots — contains, by an 

 analysis of such crop. He cannot tell how much nitrogen 

 comes from the air, and how much from the soil in which the 

 crop grew. He will hardly undertake to say that a plant 

 does not receive a larger amount of nitrogen during certain 

 conditions of the atmosphere than in others. 



The chemist can also tell us the value of and the sources 

 from whic^ we can get certain materials to supply nitrogen, 

 potash, and phosphoric acid in the best and cheapest form, 

 other than barnyard-manure ; for, unless they can be procured 

 in a cheap form, they would not be desirable. And here let 

 me say that I feel under great obligations to Professor Goess- 

 mann and to Dr. Nichols for information, at various times, 

 touching these very matters of supplying plant-food to crops ; 

 and the readiness to impart any information upon these sub- 

 jects which they possess is commendable, and deserving the 

 gratitude of the farming community. 



