EXPERIMENT STATION BULLETINS. 225 



THE INVESTIGATIONS. 

 SOILS. 



Alfalfa has been tried on many varieties of soil from the light blowing sand 

 to the heavy plastic clay and on muck. On the latter the stand has been neither 

 good nor permanent, the crop usually dying off Avithin two years from winter 

 killing combined with injury from frosts. The adaptability to muck has not been 

 sufficiently studied to warrant a final statement. Experiments are now in progress 

 to answer questions on this topic. 



On stiff clay the crop made a good growth in 1895 and 1896 but was totally 

 destroyed in the winter of 1896-7. The roots were not short, notwithstanding 

 the stiffness of the clay but extended for distances of five to eight feet into the 

 subsoil, where plenty of water was found. 



On a dry gravel bank, alfalfa has made a stand from 1897 to 190.5 and is still 

 vigorous although the stand is not thick enough for a profitable crop. A deep 

 excavation has been made at one side of the plot and the roots of the alfalfa 

 discovered at a depth of fourteen feet below the surface, the roots being at that 

 point one-fourth inch in diameter. 



On loams of all kinds, some almost pure sand and others approaching the clay, 

 alfalfa has almost invariably made a good start. Severe winters have killed 

 off the plots in almost every case, but loams seem to be the types of soil on 

 which the crop does the best. 



On sands that are carried by the wind which therefore are lacking in adhesion 

 and in humus, alfalfa seems to be rather more permanent than elsewhere. Plots 

 sown on such soil in 1897 produced good crops until 1903. It cannot be said 

 therefore that alfalfa is a crop unusually fastidious in the matter of soil. It is 

 true that stagnant water near the surface is fatal. It is probable that a very 

 stiff and impenetrable hardpan within a foot or tv/o of the surface might make 

 success impossible, but the station records give no notes on the latter point. 

 Because of its long tap root, alfalfa seems especially adapted to a deep soil with 

 the water table distant from the surface. The root hairs on slender rootlets are to 

 be found to a depth of several feet showing that the plant takes its food from 

 layers of the soil below the reach of the cereals. This fact may partly account for 

 the success on light sands. 



PREPABATION. 



It has been assumed that the crop with which we are dealing does not differ 

 from spring grain in demanding a suitable seed bed, hence it has been the in- 

 variable custom to sow the seed on ground plowed to a good depth, but not deep 

 enough to bring up a cold and unaired subsoil, well harrowed and rolled to break 

 up lumps. To compact the surface soil to establish capillary connection with the 

 subsoil is, of course, essential. 



The influence of the previous crop on the growth of alfalfa has been observed, 

 although the data is not sufficient to warrant definite statements. Where alfalfa 

 has succeeded itself after four years of cropping the new seeding has made a very 

 slow growth, possibly by reason of the exhaustion of the potash and phosphoric 

 acid. Where alfalfa has followed vetches a peculiar segregation of the nodules 

 was noted as has already been stated, page 137. So far other crops seem to have 

 been neutral in their effects on the succeeding alfalfa. 



Experiments have been undertaken to note the influence of various fertilizers. 

 None of the college soils are acid yet lime is invariably applied before the seed 

 is sown. On one series of plots a strip was sown to air-slaked lime and the next 

 to the lime cake from a sugar factory. The crop is the same over the two plots 

 showing absolutely no difference between them. The application of nitrate of 

 soda did not seem to either hasten the growth or increase its magnitude. In 

 another case the nitrate gave a visibly darker color to the alfalfa than did an 

 excess of either phosphate or potash, but the growth of the young plants is no 

 more rapid where the nitrate is applied than elsewhere. An examination of the 

 roots showed a larger number of nodules on the plot to which phosphoric acid 

 was applied and the nodules were larger. 



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