1907.] 



Utilization of Pond Mud. 



497 



It will be seen that the Kew sample in its dry state had less 

 than half the quantity of vegetable matter (and nitrogen 

 derived therefrom) contained in the other. It had, however, 

 more lime and nearly as much phosphoric acid. The fact that 

 the one sample contained so much less water than the other 

 would make the Kew sample in its natural state the richer of the 

 two. The quantity of lime would make it a useful material 

 for any land where lime is needed. 



Two other samples of mud from ponds in Kent are referred 

 to in the fifth report of the Analytical Laboratory at the South- 

 Eastern Agricultural College, Wye. Sample A was from a pond 

 which had not been " mudded " since 1836, and as neither 

 ditches nor drains run into it, the water supply has been kept 

 up only by percolation through the soil which is described as a 

 sandy clay. For many years the pond had, throughout the 

 summer, been a mass of weeds, mainly silk weed and Nymphea 

 alba. The analysis showed this mud to contain 23-3 per cent, 

 of water, 7-8 per cent, of organic matter, and -183 per cent, of 

 nitrogen. 



Sample B was from an adj acent pond into which a little ditch 

 and several drains run. It was expected that the mud would 

 be very rich and it was used as a dressing for hops. Analysis 

 showed, however, that mud was little, if any, richer than the soil 

 of the hop garden, and it had not, therefore, much value as a 

 fertiliser. It is mentioned in the report that " The fermentation 

 processes going on at the bottom of a pond are very complete, 

 organic matter is broken up into carbonic acid, marsh gas 

 and hydrogen, and free nitrogen is probably liberated also. 

 Resistant forms of organic matter would survive, but these 

 have little value as manure." The analysis showed this sample 

 to contain 52*2 per cent, of water, 7-3 per cent, of organic 

 matter, and -175 per cent, of nitrogen. 



Generally speaking, the effect of such material is as much a 

 physical or mechanical one as a chemical one, and if used on 

 land of lighter and drier texture would help in improving it. 

 On heavy land, on the other hand, it might not be so successful, 

 It should do very well as a top-dressing for grass. 



(2409) 



