A study was made with three soil extractants with a view to finding one which would be suitable for indicating changes in the levels of ammonia, nitrate, iron, manganese, aluminium and phosphorus induced by different moisture treatments during incubation of soils. It was shown that iron could be determined directly in soil extracts by atomic absorption spectroscopy. Vacuum drying over silica gel was found to be a very suitable method for decreasing soil moisture contents without affecting microbiological activity when the soils were again wetted and incubated. The effects or moisture content during incubation of soils on metabolism of ammonia, nitrate, iron, manganese, aluminium and phosphorus were studied (a) at varying static moisture contents ranging from field capacity up to waterlogging and (b) under alternate aerobic and anaerobic conditions induced by changing moisture contents during incubation from high to low levels and vice versa. The effects of moisture contents was also studied in short term incubation and pot test. The metabolism of nutrients under different moisture treatments was also studied in relation to soil pH, texture and the addition of organic materials.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:623070 |
| Date | January 1968 |
| Creators | Khan, Fazlur Rohman |
| Publisher | Imperial College London |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://hdl.handle.net/10044/1/15923 |
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