AGRICULTURE AND DENDROLOGY. 
21 
stances about 60 °/ 0 of the nitrogen applied passes over into 
the crops and as 1000 liters of excreta contain 5.5 kilograms 
of this nutrient, there may be taken up by the crop 3.3 
kilograms of nitrogen. We may illustrate such calcula¬ 
tions with the barley crop. This produces generally 1 l f 2 
parts of straw to every 1 part of grain, and the former 
contains, on an average of many analyses, 0.6 % °f nitrogen, 
the latter 1.7 %. Now, if 3.3 kilograms of nitrogen enter 
the raw crop, the grain must contain.2.16 kilograms. 
the straw .1.14 „ 
total... 3.30 ,, 
These quantities of nitrogen correspond to 
127 kilograms of grain and 
190 ,, „ straw. 
We have now to examine, whether the excreta contain 
phosphoric acid enough for this produce. Under ordinary 
conditions, such as are met with in practice, crops take up 
only about 15 °/ 0 of the phosphoric acid applied in the best 
forms of manures. Applying this measure also to the 
phosphates of the excreta, but remembering always that it 
involves the maximum effect, we find that of the 1.3 kil¬ 
ograms of phosphoric acid contained in 1000 liters of night- 
soil only 0.20 kilograms can be actually taken up by crops. 
On an average of numerous analyses, barley grains contain 
0.56 %, the straw 0.19 °/ 0 , of that nutrient, hence the 
above yield obtainable from the nitrogen alone will then 
require the following quantities of phosphoric acid :— 
0.71 kilograms for the grain and 
0.36 „ „ ,, straw. 
1.07 „ „ „ total crop. 
As only 15 °/ 0 of the phosphoric acid applied enters the 
crop, there ought to be contained in 1000 liters of excreta 
for the cultivation of barley 7.13 kilograms, while the actual 
quantity amounts only to 1.3 kilograms. Hence 5.83 kil¬ 
ograms of phosphoric acid in an easily soluble form must 
