30 



I. — All experiments show that the manure left under the beasts 

 suffers a loss of about 15 per cent, of its nitrogen ; there is no accumu- 

 lation of ammonia^ but, on the contrary, less ammonia than corresponds 

 with the digestible nitrogen in the food. This method is far from 

 being perfect ; but in comparative experiments it has always come out 

 better than any heap, and if the buildings are good and the manure 

 is well made there is probably little scope for improvement. 



Further losses set in as soon as the beasts are removed or the manure 

 is hauled out into a clamp ; in particular, there is always a loss of 

 nitrogen. 



The losses become more serious if the heap is not properly compacted 

 or if it is left exposed to the weather. Compacting only delays, and 

 does not prevent loss, especially in the heaps stored over summer. 

 Shelter from rain proved distinctly effective in conserving the crop- 

 producing power of the manure. 



2. — Manure thrown out daily. From the outset the conditions 

 are aerobic, involving marked losses of dry matter, of ammonia, and 

 to a less extent of total nitrogen, and the losses are aggravated when 

 the heaps are thrown out into the open and exposed to the washing of 

 the rain and the drying of the sun. Improvement can be effected by 

 carrying the manure into a sheltered place, such as the Cheshire dung- 

 stead or the Oxford manure house, but even the best dungstead still 

 retains some of the imperfections of the clamp. 



We think the best prospect of dealing with manure from dairy 

 cows is to aim straight away at storage in a pit or tank, and experi- 

 ments to this end are being carried out on the farm of the Hon. 

 Rupert Guinness at Hoebridge, Woking. 



The practical conclusions are : — 



{a) The method of leaving manure under the beasts in boxes or 

 covered yards until it is wanted remains the best that we can suggest 

 where it is practicable. 



{h) If the manure has to be stored it should be under anaerobic 

 conditions {i.e., complete absence of air), and if possible at a tempera- 

 ture of about 26" C. 



(c) No heap, however well compacted or sheltered, fully satisfies 

 these requirements. Probably the making of the heap has been 

 developed to as perfect a pitch as possible, and we have no further 

 improvements to suggest. 



{d) The best hope for improvement lies in storing the manure in 

 watertight tanks or pits, so made that air can be completely excluded 

 and the proper temperature maintained. 



We are hoping the experience gained in the new Woking experiments 

 will indicate a method whereby this end can be achieved in practice. 



XVI. " The Fixation of Nitrogen in Fences.'' Eric Hannaford 

 Richards. Journal of Agricultural Science, 191 7. 8^ 

 299-311. 



During the course of the preceding investigations gains of nitrogen 

 were occasionally recorded instead of losses, and on examination it 

 was found that horse faeces contain material which can be utilised by 

 the free-living nitrogen-fixing organism Azotohacter in presence of 

 sufficient moisture and calcium carbonate. The amount of nitrogen 

 that can be fixed depends on the diet, and is much reduced when the 

 horses are fed on grass alone, instead of corn and hay. 



