This year we are trying another method of sequestering carbon and it is supposed to conserve water and nutrients as well. Hugelcultur is burying wood under a layer of soil to create beds that are raised. This will not only add biomass to the garden but it will be more than double the height of our current square and rectangular raised beds, built up as a mound of woodpile, then covered completely with soil. So far the plants we have put on the mound seem happy as ever. Because it is more of a hill than a flat affair, there is additional square footage created on either side of the hill than if the soil were just flat. Just like purchasing land with slope, you get more square feet (or acreage) than if it were flat. The plants seem to love it and if the reports are correct, this will increase the nutrient content and water holding capacity of the soil for twenty years or more.