The term biomass, in general, refers to using plant and animal material to produce energy usually in the form of electricity or heat.
When the term is used in permaculture applications it has an extended meaning.
Biomass still refers to the organic material produced by plants and animals but permaculture recognizes the energy produced as more than just available for electricity and heat. Biomass can provide energy by feeding the microbiology in the soil or even feeding animals.
The important factor of biomass is an available transfer of the energy in the biomass for the purpose of providing for a whole system design.
Common Uses For Biomass In Permaculture
This is applying biomass directly to the soil providing immediate availability of Carbon and Nitrogen to the microbial life in the soil. Mulch also serves the soil in other ways such as providing shade and moisture retention. This is often applied in permaculture through what is called chop and drop, which is simply cutting parts of the plants down and dropping them around other plants.
If you are going to make large amounts of compost then you need lots of biomass to feed the compost pile. Choosing the right biomass material for compost can make a big difference in how quick your compost finishes and how much you will have available.
Biomass can provide feed for ruminants in the form of direct grazing, and “cut and carry.” By growing certain biomass plants large livestock can directly graze on the biomass for feed and small livestock can be tractored through fields of biomass for feed. Having biomass available to harvest from to take to penned or caged animals (cut and carry) is also a beneficial food source for certain livestock.
Biomass material such as animal waste, sewage and food waste can be used sometimes directly but usually through some sort of processing as fertilizer.
Even in permaculture, we make use of the obvious, not everything has to be complicated. Wood as a renewable biomass can be used to heat homes, outbuildings, and greenhouses.
Biomass can be used to produce electricity through a process known as gasification. The gasses produced in this process by the biomass can run generators which in turn provide electricity.
Common Biomass Producers In Permaculture
Leaves, limbs, and harvesting entire trees can provide thousands of pounds of biomass for use in many permaculture applications. Trees with large leaves and lots of drop such as oak and hickory are considered great biomass trees. Also, trees that grow fast and have an invasive quality like mulberry and locust are excellent trees for biomass.
I say common weeds to refer to what people commonly refer to as weeds. In most cases the weeds have great permaculture application beyond just biomass. Plants that are considered invasive are usually thought as such because of the amount of biomass they produce. This makes them a great choice for chop and drop mulch.
Plants commonly used in cover crop applications can be legumes and non-legumes. Legumes are nitrogen fixing plants providing an added bonus when used as mulch.
Plants like comfrey and curly dock are considered hyperaccumulation plants which accumulate minerals in their leaves and stems. The plants are ideal chop and drop directly around other plants and make great compost biomass.