— 61 — 
It is necessary in this connection to distinguish between 
the loots and the soil in which they have grown for while 
he roots contain, as we have seen, a large amoum of olant 
oo particularly nitrogen, it does not follow that the soil 
'tfu contains as much of this element as it did before the 
a alfa was grown in it ; in other words, if the alfalfa roots 
were removed the soil might be poorer in nitrogen 
certainly would be in other elements of plant food If the 
amount of nitrates in cropped soils be taken as the measure 
of available nitrogen in a soil, alfalfa exhausts a soTl faster 
ing ” T/e °i f Cr °f Aikman.in “ Manures and Manur- 
mg, page, i 0 7, quotes the amount of nitrates found in 
appears that ^hb^blw^?™ 3 ^ S ° Us) ’ from which 
ppears that there is the following amount of nitrotren as 
nitrates in each acre of soil taken to the depth of nine feet 
n soil cropped to white clover, 102.8 pounds; to vetches 
54.6 pounds; to wheat, after fallow, 18.4 pounds and to al ’ 
ff \V° P u° und ®’. 11 is further shown for the soil crooned 
to alfalfa, that while the first nine inches of soil contains 
“ightTeefthreelnr? ^ ^ n ‘ f ne ‘ nches taken ’ that is - from 
“ . eet three inches to nine feet, contain onlv o a nounrk- 
while in the soil cropped to white clover there^at the 
same depth (eight feet three inches to nine feet) too 
oounds, showing how great a draft the alfalfa had made 
.ipon this form of nitrogen in the soil. 
ablef! suggesdve j act shown by the figures of the 
able as quoted, 1 e. the first nine inches of soil contain 
he 6 dloth o? 3 tnfl f e CSS ll ] an one - fifth of the ^^1 taken to 
ifter a?fa h lfa f tI !r’ and . more than one-half of the total 
alfa is Mm net- Th e. dlm unition of the nitrogen after the al- 
nches Where COntlnuou f to the depth of eight feet three 
! ’ ds « lven above . the amount of nitric nitrogen 
S only 0.4 pounds per acre; while in the other cases the 
md three feej^^ 5113 n ] ax , lmun ? at a depth of between’two 
nrreafeh^ ’ f , ™ hlch P olnt on the nitric nitrogen 
creases somewhat, being present in the largest quantity 
fter white clover at a depth of four and one-half to six feel 
L an , n e hg T es glve , n ln , this connection show more clearly 
h hich aL?f h f rS 7 lth r W , hat avidity and also the depth to 
hich alfalfa feeds. I do not think that the movement of 
l e nitric nitrogen (nitrates) in the soil can operate to pro- 
uce this marked result in the case of the alfalfa, but that 
ie nitiogen is appropriated by the plant. 
LEAVES AND STEMS AS A TOP DRESSING. 
It has been repeatedly stated that the mechanical loss 
1 making alfalfa hay is very considerable, and while I have 
