FARMYAKD MANURE. 25 



to be manured. On the whole, I think autumn manuring greatly 

 preferable to spring manuring, even in the case of moderately 

 strong land. On stiff clay soils farmyard manure should always 

 be used in autumn, and, if possible, be ploughed in before the 

 frost sets in. By this means the full advantage of manure is 

 secured, for, in addition to the chemical effects which manure is 

 capable of producing, it will exercise upon stiff clays a most bene- 

 ficial mechanical effect by keeping the land more porous and 

 open. On the other hand it is not desirable, for obvious reasons, 

 to apply manure in autumn to very light sandy land. 



As in the beginning of this lecture 1 have treated many inte- 

 resting points with reference to farmyard manure in a very cursory 

 manner, I beg to refer those who wish to study more fully the 

 chemistry of farmyard manure to a paper of mine, published in 

 the ' Journal of the Royal Agricultural Society of England,' 

 July, 1856. Before concluding, however, I may be permitted to 

 state the following general conclusions, to which a series of similar 

 experiments to those referred to in this lecture have led me : 



CONCLUSIONS. 



1. Perfectly fresh farmyard manure contains but a small pro- 

 portion of free ammonia. 



2. The nitrogen in fresh dung exists principally in the state of 

 insoluble nitrogenized matters. 



3. The soluble organic and mineral constituents of dung are 

 much more valuable fertilizers than the insoluble. Particular 

 care, therefore, should be bestowed upon the preservation of the 

 liquid excrements of animals, and for the same reason the manure 

 should be kept in perfectly waterproof pits, of sufficient capacity 

 to render the setting up of dungheaps in the corner of fields, as 

 much as possible, unnecessary. 



4. Farmyard manure, even in quite a fresh state, contains phos- 

 phate of lime, which is much more soluble than has hitherto been 

 suspected. 



5. The urine of the horse, cow, and pig, does not contain any 

 appreciable quantity of phosphate of lime, whilst the drainings of 

 dungheaps contain considerable quantities of this valuable fer- 

 tilizer. The drainings of dungheaps, partly for this reason, are 

 more valuable than the urine of our domestic animals, and there- 

 fore ought to be prevented by all available means from running 

 to waste. 



6. The most effectual means of preventing loss in fertilizing 

 matters is to cart the manure directly on the field whenever cir- 

 cumstances allow this to be done. 



7. On all soils with a moderate proportion of clay no fear need 

 to be entertained of valuable fertilizing substances becoming wasted 

 if the manure cannot be ploughed in at once. Fresh, and even 



