542 TRANSACTIONS OF SECTION M. 



clover residues to benefit succeeding crops. How would a dressing of potash 

 and pTiosphates to the clover react on the next crops ? Practically no farmer 

 gives it ; would it not be worth while ? These and similar questions can only be 

 answered by actual experiments, and in view of the importance of making the 

 best use of our manures over the whole rotation, it is desirable that they should 

 be put in hand. 



Another direction in which great economy is possible is in the management 

 of farmyard manure. It has be«n a common complaint against agricultural 

 investigators that they have concerned themselves exclusively with artificials, 

 and left untouched the greater problem of the manure-heap. For farmyard 

 manure is the staple manure of the countryside ; no direct estimate of the 

 amount used annually appears to be available, but the statistics show that 

 9^ million tons of straw, wheat, barley, and oats, are grown in the country. 

 If we assume that all this is made into manure, and that one ton of straw 

 gives on an average four tons of manure, we arrive at 37 million tons of 

 farmyard manure made per annum. The value at 5s. per ton is 9,250, OOOL ; 

 all the artificial manures consumed in Great Britain probably do not much 

 exceed 6,500,000?. in value each year. 



Through the generosity of the Hon. Rupert Guinness, we Jiave been able 

 at Rothamsted to attack this important subject, and Mr. Richards has obtained 

 some striking results, showing what losses may take place and indicating 

 methods of avoiding them. The great sources of loss are the air and the 

 weather. Heaps made up in the orthodox manner — compacted but left out in 

 the field without shelter — lost in three months 39 per cent, of their dry 

 matter and 87 per cent, of their original ammoniacal nitrogen. When the 

 heap was stored under cover the loss was smaller, being 30 per cent, of the 

 dry matter and 55 per cent, of the ammoniacal nitrogen, so that the provision 

 of shelter added materially to the value of the manure. These analytical 

 results were confirmed by field trials. Ten tons of the sheltered manure 

 gave nine tons of potatoes per acre, against 7"4 tons given by ten tons of 

 the exposed manure. Reckoning the potatoes as worth 70.?. per ton, the extra 

 crop obtained by sheltering the manure is worth 5?. 12.s. per acre, without 

 taking into account the fact that less dung is required to make ten tons of 

 sheltered manure. 



But there is still a loss even from the sheltered heaps, amounting in our 

 various experiments to some 50 per cent, of the ammoniacal nitrogen, and 

 some 30 per cent, of the total. Below this we see no way of going at present 

 so long as the manure is stored in heaps. Laboratory experiments, however, 

 indicate a much better method of storage. 



If the manure is kept entirely out of contact of air it can be preserved 

 absolutely without loss; and if,, further, it is warm enousih (about 26° C.) 

 it will even improve by the ammoniacal fermentation Avhich sets in. No 

 heap we have seen in practice reaches this happy condition, and we have no 

 indication that any heap ever could. The only perfect storage would appear 

 to be in pit« or tanks that could be closed absolutely air-tight. Whether this 

 could be done in practice is a matter that can only be settled by experiments. 

 These we hope to put in hand next season, and in the first instance we are 

 starting with liquid manure, the storage of which, especially on dairy farms, 

 is admittedly a weak point in farm management. 



Another direction in which saving is possible is in the soil itself. It 

 is now 46 years since Lawes and Gilbert built those remarkable drain gauges 

 at Rothamsted which for the first time enabled chemists to determine pre- 

 cisely the quantity of fertilising material washed out from the soil by rain. 

 When there was no crop on the ground the soil lost by drainage about 40 lb. 

 of nitrogen in the form of valuable nitrates, a quantity as great as is con- 

 tained in a 24 lb. bushel crop of wheat. This was "soil without manure. 

 More recently the subject has been investigated in another way. The amount 

 of nitrate in certain plots has been determined at ten days' intervals for a 

 period of two years. In the early part of the year the nitrate is low in 

 amount ; it rises rapidly in spring or early summer — the rise coinciding with 

 the rise in soil temperature. During summer there is considerable increase in 

 fallow land, but not in cropped land — partly because the crop is taking up 



