1908.] 



Farmyard Manure. 



7i 



the great accumulation in the soil of the residues of 30 years' 

 previous manuring with dung. Only the nitrogen was 

 concerned in these differences because both the plots 

 received the same phosphoric acid and potash. Moreover 

 the crop had by no means reached its limit, for an addition 

 of nitrate of soda to the dung increased the crop to 41*4 tons, 

 and here again only the nitrogen is concerned because on a 

 further plot where phosphoric acid and potash were added 

 to the combination of dung and nitrate of soda there was but 

 a very slight additional increase of crop. 



From other experiments it has been repeatedly demonstrated 

 that where the grower is aiming at a very large crop it is more 

 economical to attain this by using dung and a mixture of active 

 artificial fertilisers than by increasing the amount of dung ; 

 20 loads of dung, with 1 to 2 cwts. of nitrate of soda and 3 cwts. 

 of superphosphate costing about 30s., will generally be more 

 effective than 40 loads of dung, the second 20 loads which 

 cannot be charged at less than £4 or £5. 



Farmyard manure has frequently been blamed for carrying 

 the seeds of disease and of weeds in an unchanged condition 

 and thus contaminating the land for other crops. When 

 bullocks have been fed with swedes affected with " finger and 

 toe " and the uneaten fragments of the roots are thrown 

 among the litter, the spores of the disease have been found 

 to live unharmed through the making and rotting of the 

 manure, so that fresh land may thus become infected when 

 the dung is carried on to it. Similarly when hop bines are used 

 as litter the spores of the hop mildew are not destroyed, but 

 no other cases of transmission of disease have been investigated. 

 As regards weeds, farmyard manure is most commonly 

 employed for root crops, in which case the usual cultivations 

 will keep down any weeds whose seeds are in the dung, and 

 when the dung is put on grass land the weed seeds stand little 

 chance of establishing themselves. 



The value of farmyard manure to the land is, however, by 

 no means confined to its fertilising action ; its physical effects 

 upon the texture and waterholding powers of the soil are 

 equally important, indeed for some crops and particularly 

 in droughty seasons they count for more than fertilisers 

 towards ensuring a good yield. The farmyard manure as it 



