Q# 3 Problem set No. 3

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Calculate kg of calcium and potassium per hectare (10000 m^2), when soil bulk density is 1350 kg m-3, and a soil sample was obtained from the 0-20 cm layer. The concentration of calcium is 50 mg kg-1 and concentration of potassium is 103 mg kg-1

do we give our answer in hectares at a depth of 20cm? ha 20cm or hectare meters? (hectares at a depth of 1m)

will the markers understand our answer?

The answer should be in kg per ha (as specified in the question no.3) To be able to get your answer in these units, you will 1st need to calculate the mass of a soil layer that has dimensions of 100 m by 100 m and depth of 0.2 m (specified in the question). This is very similar to a question from the problem set no.1

After calculating the mass of the soil layer, do I simply multiply the concentration of calcium by the mass? I would end up with an answer with mg as the unit. Do I then convert mg to kg/ha? How do I do that?

The layer of the soil (for which you calculated its mass) has area of 1 ha (which is 100 m by 100 m); hence, the only conversion that you need to do is from milligrams to kg.