584 ST&.TE HORTICULTURAL SOCIETY. 



This living together of the leguminous plant, and the adventitious 

 organism for mutual benefit, is frequently met with in the vegetable 

 kingdom, and is called symbiosis. It is a purely business relation, and 

 when either host or visitor overtakes and crowds out the other, the 

 death of both results speedily. The organism, it is to be presumed, 

 demands for its development the existence within the host of certain 

 favorable conditions, which doubtless prevail in all leguminous plants, 

 -and impart to them their important property of being able to live on 

 free nitrogen. May not other plants be made to acquire it also ? Until 

 then, we have learned, however, which crops may and which may not 

 be employed for purposes of green manuring : the knowledge must now 

 be supplemented by actual trial to render it practical. Whether clover, 

 peas and vetches, serradella or lupines answer best under our condi- 

 tions of soil and climate ; whether to grow them as main crops and lose 

 the use of the land for the season, or to sow with others and secure a 

 crop along with a long period of growth; whether to plow in at all or 

 feed to cattle and save the manure to return to the land; and lastly, 

 whether to buy mineral fertilizers to stimulate an abundant growth of 

 leguminous crops for feeding, followed by a grain crop or a crop of roots 

 or tubers for two or three years to begin the rotation again, are all ques- 

 tions that practical and patient trial alone will answer ; and such an- 

 swer in the form of a few plain rules is the hope of agriculture, and, 

 when formulated, the staff upon which the general farmer will lean 

 with safety. 



