RETURN OF MATERIAL TO THE Hop Root. 478 

evident from the increased proportion of ash in the dry matter, 
for no access of fresh mineral material is likely to have taken 
place, the amount has only increased relatively owing to the 
loss of the other non-mineral dry matter. But even the dry 
matter of the dead leaves is poorer in nitrogen and potash, 
though slightly richer in phosphoric acid than the dry 
matter of the green leaves. 
In calculating from these analyses the quantities of mate: 
rial returned to the root stock during the ripening of the 
plant after the hops have been picked, it is necessary to 
make estimates of the weights of dead bine and leaves, for 
the actual amounts cannot be ascertained with accuracy. 
As regards the bine, the weight of dry matter per acre 
will be less when dead than when green, because both com- 
bustible material and mineral matter will have been with- 
drawn; but to get any trustworthy idea of the extent of 
this loss of weight it would be necessary to compare the 
weights of green and dead bine over a considerable area. 
A trial of five hills only of each gave 17 ozs. of dry matter 
per hill when dead, against 21 ozs. of dry matter when green, 
and another comparison made by carefully matching equal 
lengths of bine of various thicknesses gave a dry weight 
of 117 for the dead bine against 127 for the green bine. 





Percentage. Lbs. per acre, 
In Green In Ripe In Green In Ripe 
Bine. Bine. Bine. Bine. 
Dry Matter - - - 100 100 | 1289 | 1289 
Ash - - - - 6°04 4°83 | 77° 62°2 
Nitrogen - - - "984 347 | 27) 4°5 
Lime - - - - 1°85 | 2°28 | 23°0 29°4 
Potash - : : - 1°04 ig) | iA Tee7 
Phosphoric Acid - - 2377 | ‘O81 4°77 1.04 




It will, however, be sufficient for the present to regard the 
dry weight of green and dead bine as the same, the more 
so as the unknown error thus introduced will only diminish 
