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Good question! You are definitely on the right track with your answers, but there is more to add. Think 1st, under what conditions there will be lots of leaching of any ion? Key factors include: a) Abundance of water in the soil, b) Ions predominantly present in the soil solution, b) Abundant source of a specific ion c) Soil mainly has large pores that are filled with water

... now for each of those key factors, think about soil (or climate for factor "a") properties that would contribute to it. For example, soil will end up having predominantly large pores, when it is very coarse textured (ie dominated by sand) and with no aggregate formation.

Instead of me completing this answer, I'll leave it for you (and your colleagues, who are hopefully reading this) to complete the answer for the sulfate ions

So, the following enhances sulphate leaching:

- Abundance of water in the soil due to high precipitation and moderate water retention to dissolve the ions into soil solution within the macro pore spaces . But also having moderate to good drainage so the dissolved ions in solution can permeate through macro pores and exit the soil profile.

- Coarse textured soils that have macro pores will allow the soil water to percolate down the profile. In addition poor aggregation from lack of biotic activity or high sodium levels will contribute to a granular structure that favours macro pores.

- High abundance of sulphate ions in soil profile to begin with. Added by decomposition of organic matter, acid rain from atmospheric sulphur or the chemical weathering of minerals.

- High pH levels will increase sulphate leaching as there is less adsorption by colloids.