Liquid Manure. 1 



The preceding analytical results suggest the following re- 

 marks : 



1. It will be noticed that liquid manure in contact with soil 

 parts with a considerable quantity of ammonia, which, in some 

 form or the other, is taken up by the soil. In this experiment 

 soil and liquid manure were employed in the proportion of 2 

 of soil to 7 of liquid. A gallon of liquid manure in this experi- 

 ment yielded to 20,000 grains of soil 14'77 grains of ammonia ; 

 accordingly, 1000 grains of soil absorbed "738 grains of ammonia. 

 Whether this is the maximum proportion of ammonia which 

 this soil is capable of absorbing, or whether it would have taken 

 up more or less ammonia when mixed with liquid manure in a 

 different proportion than in the experiment, I am unable to tell 

 for the present. It appears to me, however, probable that the con- 

 centration of the liquid in some measure determines the amount 

 of ammonia which is retained by the soil. 



Referring to a previous experiment with drainings of dung- 

 heaps. I find that 11,000 grains of a similar soil to the one from 

 field No. 19 absorbed only *365 grains of ammonia, or about 

 half the quantity. These drainings of a dungheap originally con- 

 tained 19'68 grains of ammonia to the gallon, and after filtration 

 through soil 6*91 grains. 



Further experiments with different descriptions of ammo- 

 niacal manuring matters and the same kind of soil are necessary 

 before it can be decided whether the quantity of ammonia ab- 

 sorbed by a particular soil is constant, or whether it is influenced 

 by the concentration or chemical composition of the manuring 

 liquids with which the soil is brought into contact. 



2. The amount of organic matter in the liquid manure em- 

 ployed in the experiment was less before than after filtration 

 through the soil. Pure distilled water left in contact with 

 arable land, I have shown before, extracts a considerable propor- 

 tion of organic matter from the latter ; and as the liquid manure 

 originally contained but little, it need not cause surprise that it 

 dissolved more when brought into contact with a soil containing 

 a fair proportion of decomposed vegetable remains. The in- 

 crease in organic: matter accounts for the somewhat larger pro- 

 portion of nitrogen in the organic portion of the filtered liquid. 



3. On the other hand, the total quantity of mineral matter in 

 the liquid manure after digestion with the soil has diminished in 

 about the same proportion in which that of organic matter has 

 increased. 



4. It is worthy of notice that the liquid manure originally con- 

 tained no oxide of iron. Left in contact with soil it dissolved 

 2'55 grains per gallon. The liquid analysed was perfectly clear, 

 and the oxide of iron found cannot, therefore, arise from any 

 suspended particles of soil. I have, moreover, repeated the 



