626 Abstract Report of Agricultural Discussions. 
THe following calculations will sliow the effects, both on the land 
and the animal, resulting from this system : — 
An acre of turnips = 15 tons. 
Amount of nitrogen left in manure made from turnips, 74 lbs. 
Amount of mineral matter, 300 lbs. 
The analysis of the mineral matter gives : — 
Per Acre. 
, lbs. 
110-94 Potash 36-98 
20-28 Soda 6-76 
1-77 Chloride Potassium -59 
23-55 Common salt 7-85 
10-83 Magnesia 3-Gl 
33-42 Lime ll'M 
29-22 Phosphoric acid 9-74 
37-29 Sulphuric acid 12-43 
10-29 Silica 3-43 
3-27 Iron 1-09 
19-14 Carbonic acid 6-38 
300-00 100-00 
Such would be the manuring value of an acre of turnips consumed by 
sheep eating 20 lbs. of roots daily, with no dry food. If we substitute 
\^ lb. of straw for 10 lbs. of tiu-nips, it follows that with every acre 
of tm-nips 2 tons 4 cwts. of straw will be eaten. Straw on an average 
yields per cent, of nitrogen ; therefore 2 tons 4 cwts. = 24-6 lbs. ni- 
trogen, of which 21-6 lbs. is left as dimg, probably about one-eighth 
part being consumed in exhalation from the animal's skin, &c. The 
same quantity of straw will yield 221-1 lbs. of mineral matter as 
manure. Of this a considerable portion, about 48 per cent., is silica ; 
but the remainder contains minerals which are very valuable as plant 
food. The addition to the soil of this large amount of silica, in 
round numbers about 107 lbs., in a condition available for plant food, 
would act beneficially on the following barley crop, which requires, for 
grain and straw, more silica than any of the other cereals. 
Quantity returned 
Analysis of Ash of Oat-straw. 
per Acre as Manure. 
lbs. 
19-14 .. 
.. 42-29 
Soda 
9-G9 .. 
.. 21-41 
3-78 .. 
8-35 
8-07 
.. 17-83 
Phosphoric acid .. 
2-5C ., 
5-65 
Sulphuric acid 
.. 3-26 ,. 
7-20 
48-42 .. 
., 107-00 
Peroxide of iron .. 
.. 1-83 .. 
4-04 
Common salt 
. . 3-25 .. 
7-18 
100-00 
220-95 lbs. 
We may fairly calctdate that by giving ewes \\ lb. of straw per day 
•wo increase the value of the manure by more than one-half. Many c/f 
