Hügelkultur
[5] Joined by author Hans Beba, another German gardener, "Hill Culture - the horticultural method of the future" was revised and republished several times in the 1970s and 1980s.
[9] In its basic form, mounds are constructed by piling logs, branches, plant waste, compost and additional soil directly on the ground.
(Note—Wheaton suggests piling the wood higglety-pigletty rather than in a neat stack as shown, for structural engineering of the steep slope, or perpendicular to the spine of the mound.)
[5] One small scale and short term student project investigated the Hügelkultur method as a potential use for yard trimmings waste, and also if lima beans, kale and okra planted on a Hügelkultur mound showed any signs of nutrient deficiency compared to a non-raised control bed.
It was found that over 11 tons of yard trimmings were used in the mound, and no evidence of macronutrient deficiency could be detected in the crops in the short term.
[14] The author speculated that no nitrogen deficiency occurred since the roots of the plants did not penetrate past the superficial layers of the mound into the deeper wood-containing region.
[14] A student thesis investigated the water holding capacity of Hügelkultur beds and whether the technique could be useful to prevent karst rocky desertification in China.
It was suggested that 1 ha (2+1⁄2 acres) of hügels has 3-10 times more water than a flat plot affected by karst rocky desertification.
[15] A 2024 study comparing different permaculture approaches found increased carbon content in soils treated with Hügelkultur, and reduce waterlogging.
If the wood is not processed into smaller pieces with larger surface area to speed up chemical reactions, breakdown is even slower.
Whereas embankment dams or the hillsides of swales can be relied on to hold back many thousands of gallons of water for weeks to allow it to seep into the ground, and berms can slow runoff, Hügelkultur beds are different in two ways: earthworks have no buoyant core (whereas Hügelkultur mounds contain logs), and the soil that they are made of is compacted.
If fresh or dried timber is used in the bed, it may become buoyant in the water-saturated substrate, bursting from the soil covering and releasing all the sitting water through a breach.
Hügelkultur is used for shorter term, more annual crops, as the soil settling that occurs with hugel decomposition is bad for the root system of fruit trees.
The released water carried the freshly-buried logs and dirt downhill, smashing a hole in a building being used as a church and filling the space with mud.
[21] It has been suggested that excessive use of decomposing organic matter in Hügelkultur could leach out and contaminate and disrupt soil and water habitats.
