292 State Horticultural Society. 



Sources and relations of important nutrients — It has been 

 abundantly demonstrated that the matter of supplying sufficient 

 nitrogen to the soil, or of maintaining the nitrogen supply, is not 

 a very serious problem in modern agriculture. For those so sit- 

 uated that they can afford it, stable manure is a good source of 

 nitrogen, as well as a general fertilizer; but nitrogen can also be 

 cheaply supplied to an orchard soil by means of leguminous crops, 

 and at least the occasional growing of leguminous crops in the or- 

 chard should be made a permanent factor of orchard culture. We 

 cannot exhaust the supply of atmospheric nitrogen, and it is chiefly 

 this atmospheric nitrogen that leguminous plants appropriate. 



In order to supply a nitrogen need, the peculiarities of soil and 

 other conditions must be considered before determining upon a 

 leguminous crop to be used. In the selection of the leguminous 

 crop, one should consider the matter of soil acidity. It is a matter 

 of common knowledge that neither alfalfa nor crimson clover suc- 

 ceed well upon acid soils, probably owing most particularly to the 

 fact that the nitrogen-fixing bacteria are not accommodated to such 

 acid conditions. Such experiments as have been made in the far 

 east, however, seem to demonstrate that cowpeas may thrive in 

 an acid soil ; therefore, if the matter of liming is one which is tem- 

 porarily attended by difficulty, the growing of cowpeas in a slightly 

 acid orchard would be desirable from the standpoint of the amount 

 of growth of the leguminous plant which might be attained. The 

 problem of nitrogen storage in soils or improvement of soils is, 

 however, essentially bound up in that of liming for the correction 

 of great acidity, since, if a leguminous crop is plowed under as 

 green manure, there should be present sufficient lime to assist in 

 its proper decomposition. Furthermore, if leguminous crops un- 

 common in the region are attempted, the matter of soil inoculation 

 must not be neglected. 



The effects of lime upon plants are somewhat more complex 

 than those of the other elements mentioned, for while lime may 

 act directly as a plant food or nutrient, it may act indirectly in 

 a variety of ways, such as the following : 



1st. It has an ameliorating action upon magnesia when the 

 latter is in excess in the soil. In a large number of the soils of 

 Missouri it is doubtless true that the lime has in great measure 

 leached out and magnesia has been left in excess. It has been 

 shown that an excess of magnesia may be extremely injurious to 

 many crops. The work of Doctor Loew, formerly of the United 

 States Department of Agriculture, brought out verj^ clearly the 



