Based on laboratory studies with lysimeters, the concentrations of dissolved reactive phosphorus(DRP) and particulate phosphorus, which is the main part of other P (OVRP), has been studied inpercolating water. The experiment was conducted through irrigation of small soil columnscontaining clay topsoil from an experimental field in Västergötland. Three rain simulations wereconsecutively performed. DRP concentrations in the percolating water ranged between 0.2 - 0.3mg·L -1 . The amount of DRP percolating from four soils with different fertilization history wasclearly related to the phosphorus concentration in the soil, measured in a soil extract ofammonium lactate (P-AL). Concentrations of OVRP were relatively low and ranged between0.12 and 0.16 mg·L-1 in the percolating water passing through the topsoil. Any macropore flowwas not proven and the experiment may reflect how a relatively slow percolation of water mayrelease DRP. In contrast, from observed fields with drainage systems quite high concentrations ofOVRP are typically recorded. This is generally explained by fast flows through macropores in thesoil and through the drain tile systems. Solid manure was applied to the lysimeters equal to a normal agricultural load (30 tons per ha),and thereafter another three rainfall were simulated. The load of manure increased the leaching ofDRP approx. 7 times. The largest increase was observed from the soils with the highest P-AL-numbers. The relative boosts of DRP after manure application increased linearly relative to the P-AL number of the soil and with a high correlation coefficient. Thus the results from the manureaddition indicated that the soil with highest phosphorus concentrations released proportionallymore phosphorus than soils with low P-AL numbers. The studies demonstrate the importance ofadjusting the load of manure to the soil phosphorus content. Presently the spreading of manure isonly restricted by the number of cattle/cultivated land, not to the P-AL number of the soil.
| Identifer | oai:union.ndltd.org:UPSALLA1/oai:DiVA.org:uu-111172 |
| Date | January 2009 |
| Creators | Johansson, Pontus |
| Publisher | Mark och miljö, SLU |
| Source Sets | DiVA Archive at Upsalla University |
| Language | Swedish |
| Detected Language | English |
| Type | Student thesis, info:eu-repo/semantics/bachelorThesis, text |
| Format | application/pdf |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | UPTEC W, 1401-5765 ; 09 026 |
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