Why add biomass

Biomass plays a crucial role in moisture retention in a forest garden, enhancing its sustainability and resilience.

1. Improved Soil Structure

  • Organic Matter: Decomposed biomass, such as leaves, wood chips, and plant debris, increases the organic matter in the soil. This improves soil structure, making it more porous and better able to retain water.
  • Aeration and Drainage: Biomass creates a balance between aeration and water-holding capacity, preventing waterlogging while maintaining sufficient moisture.

2. Mulching Effect

  • Evaporation Reduction: A layer of biomass mulch (e.g., straw, wood chips, or leaf litter) covers the soil, reducing direct exposure to sun and wind, which minimizes evaporation.
  • Temperature Regulation: Biomass acts as an insulating layer, keeping the soil cooler in summer and warmer in winter, stabilizing the moisture levels.

3. Water Absorption and Storage

  • Spongy Material: Biomass like rotting logs and decaying plant material acts like a sponge, soaking up water during rains and slowly releasing it to the soil during dry periods.
  • Hydration Buffer: Forest gardens benefit from this reservoir effect, which ensures plants have access to water over time.

4. Soil Microbial Activity

  • Fungal Networks: Biomass encourages the growth of beneficial fungi (e.g., mycorrhizal fungi), which form networks that transport water and nutrients to plants.
  • Microbial Health: Decomposing organic matter supports a thriving soil microbiome, improving the soil's ability to retain and distribute moisture effectively.

5. Prevention of Soil Erosion

  • Ground Cover: Biomass protects the soil surface from heavy rainfall, reducing runoff and allowing water to penetrate the soil.
  • Binding Soil Particles: Organic matter helps bind soil particles, maintaining the soil’s capacity to hold water even on slopes or exposed areas.

6. Carbon Sequestration

  • Biomass locks carbon into the soil, which helps improve soil quality and its water-holding capacity over the long term.

7. Nutrient Retention

  • Water-Holding Nutrients: As biomass decomposes, it releases nutrients slowly, and these nutrients are more effectively held in the moisture-retentive soil.
  • Prevents Leaching: Moist, biomass-rich soil reduces nutrient loss through leaching, especially during heavy rains.

8. Long-Term Resilience

  • Drought Mitigation: In dry periods, biomass retains moisture longer, reducing the need for supplemental watering.
  • Plant Health: Consistent moisture levels lead to healthier plants with better root systems and increased resistance to stress.

Practical Applications in a Forest Garden

  1. Mulching: Apply thick layers of organic mulch around plants to retain moisture and suppress weeds.
  2. Hügelkultur Beds: Incorporate buried logs and woody debris to create water-retentive raised beds.
  3. Chop-and-Drop Mulching: Periodically cut down cover crops or herbaceous plants and leave them on the soil to decompose.
  4. Compost: Add decomposed organic matter to increase water retention and nutrient availability.
External inputs

External inputs

March 31, 2015
One of our aims is to eventually reduce or eliminate the need for external inputs for the orchard and garden. The goal is to keep fertility on site and make the most of that which enters naturally, such as rain and bird droppings. In the meantime, as we work towards this, there is always a use for biodegradable organic matter.

Commonly used materials include: sawdust from local joiner, seaweed from Kaikoura, rotten willow logs from the river, pine needles, organic grain straw, Conway river lime and dried animal manures.

 Related

Log Swale / Hugelkultur

Log Swale / Hugelkultur

There is a theory that burying rotting logs can improve the water retention and that plants growing above can tap into that water trapped in the rotting 'sponge' of wood.

Since we had the digger on site I figured we should give it a go - stay tuned for results on this
October 12, 2011
  Water  Drought  Digger  Swale  hugelkultur 
olmec
Read More
Hugelkultur gardens in summer

Hugelkultur gardens in summer

Details   Every year, since their construction, our hugelkultur raised woody garden beds have been improving in performance. While waiting for the perennial plantings to establish we have been gardening with seasonal crops including maize, pumpkins, tomatoes, salad, cucumbers and of course lots of beans. Modest additions of straw mulch, trenched in pig manure, compost tea and all plant residues are contributing to the overall fertility of the beds and on occasion where I have exposed the wooden core while digging it is clearly breaking down into a crumbly organic 'compost'.
Date   February 18, 2018
Tags     garden  hugelkultur  2018  summer 
Some specifics
Mulch, soil carbon and organic matter to improve moisture holding

Mulch, soil carbon and organic matter to improve moisture holding

Mulching is the practice or process of covering the soil with a thick layer of organic matter. This has a number of benefits depending on the mulch material and desired outcomes. Some of the advantages include preventing moisture evaporation, smothering weeds, feeding soil life and increasing soil carbon and water holding capacity.
Use as much mulch as you can get your hands on.
June 06, 2015
  mulch  carbon 
olmec
Building great soil
Raised woody swale / hugelkultur construction

Raised woody swale / hugelkultur construction

Details   We used the opportunity of having a small excavator on site recently to construct 5 wood filed raised growing mounds on contour.
This technique is often called hugelkultur and exploits the ability of rotten wood to absorb and hold amazing quantities of water which is later made available to plants growing nearby.
The end result was 5 mounds about 7 meters long and half a meter high, each packed with a full trailer load of rotten willow logs and a wheel barrow of pig manure.
An assortment of fruit trees and berry shrubs has been planted along side in various locations to capitalise on the moisture, slow release of minerals and micro-climate effects of wind, shelter, sun and shade.
Date   July 25, 2014
Tags     swale  digger  water  hugelkultur 
View 4 photos