The swale mound should always be planted with ‘something’ soon as it’s piled up on the lower edge. Needless to say, it should not be compacted. When it’s still fluffy, it can be sown with a pioneer ground cover or legume crop. The piled soil, as at pointReturn bereft of any worthwhile topsoil, is likely to be infertile. So a pioneer crop serves as a green manure that can be chopped and dropped before it seeds. The residual roots become feed stock for soil animals and the dropped biomass becomes mulch. It may then be ready to be planted out with chosen tree crops.
If on the other hand, the swale is being dug on a fertile property, the topsoil is carefully removed and placed on the upper edge. Digging and piling up of the undersoil proceeds as before. Finally, the reserved topsoil is transferred on top of the mound, created on the lower edge. It may then be sown with a pioneer crop.
Getting the swale mound quickly covered has three benefits. One, cover crop roots anchor the soil against erosion and prevent compaction. Two, the soil is fertilised naturally and quickly. And three, when trees are planted out, the mound comes readily mulched to retain moisture.
It’s been just over 3 months since my affair with swales began. In that time three swales have emerged spread over a 3 acre area. They take up 0.2 acres and have a total capacity to trap 400,000 litres of rainwater, every time they are filled. And they have been filled once already. They constitute about 20% of the planned swale work. As I write, my heart and the pond are full; the road ahead looms clear. Swales are the way to go and reach water security at pointReturn.