Test-mineral bags

The in situ soil bag method involves the insertion of known amounts of exchange resins or of pure test-minerals in permeable bags. These are placed back in the soil profile, left to react under field conditions for years and then removed for the purpose of analyzing mineralogical changes. The method is presented in detail in the section on results from Skogaby and Rakaledin in Sweden. 

Explants were excised at midpodfill and their bases were placed in test solutions containing halfstrength mineral nutrient solution [3] and 10 M ZR in order to approximate the composition of the xylem sap which carries the senescence signal. The explants were incubated inside clear plastic bags through which humidified air (80+ % R.H.) was blown. 

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