78 



MANURES. 



evidence is thus presented in the analysis of these liquids, tliat as 

 the draiiiings of both fresh and rotten dung-heaps are allowed to 

 flow into the next ditch, concentrated solutions of the most valua- 

 ble constituents of dung are carelessly wasted. 



With a view of preventing such a serious loss, I have suggested 

 the propriety of carting the manure on the fields, whenever prac- 

 ticable, in a fresh state, and of spreading it at once. It may be 

 objected that the application of manure in a fresh state, equivalent 

 to winter manuring, and especially the spreading of dung, will lead 

 to waste, inasmuch as the rain which falls during the winter and 

 spring has much more chance of washing out fertilizing substances 

 from the dung than by applying it at the time of sowing. This 

 objection would indeed be a valid one, if we were not acquainted 

 with the fact that all soils containing a moderate proportion of clay 

 possess the property of retaining the more valuable constituents of 

 manure ; but, this being the case, the objection on these grounds 

 cannot be admitted. With more force, however, it may be made 

 with reference to light sandy soils, and it is indeed upon such soils 

 that manure is best applied in spring. 



In order to ascertain to what extent various soils possessed the 

 powers of absorbing manuring constituents from the drainings of 

 dung-heaps, I determined to employ a limited quantity of soil and 

 a large excess of liquid. To this end, two parts by weight of liquid 

 were well mixed with one part by weight of soil, and left in con- 

 tact with the latter for twenty-four hours, after which the clear 

 liquid was drawn oiT and passed through a filter. 



« 



Experiments to Ascertain tee Extent of Absorbing Properties op 

 Soils of Known Composition. 



Experiment made with the drainings of dung-heaps composed 

 of rotten dung. The drainings employed in this experiment were 

 the same which contained in the imperial gallon 664.64 grains of 

 solid matter, the detailed composition of v/hich is given above. 

 The composition of the soil used in the experiment is given below. 



The surface-soil contained a good deal of organic matter, a fair 

 proportion of clay, little sand, and a moderate proportion of car- 

 bonate of lime in tlie form of small fragments of limestone. It was 

 a stiffish soil, belonging to the clay marls. Its subsoil was richer 

 in clay and of a more compact texture and less friable character 



