This
past winter we began converting the three largest beds at the Sebastopol Energy
Garden into a broad acre demonstration plot. The initial steps of converting the
beds into a 528 ft² field entailed building up the soil with compost that was
produced on-site, and broadcasting alfalfa and white clover seed onto the plot.
We planted the two legumes separately so as to compare their performance as
living mulch. Both can sustain a mowing, and both will grow perennially in this
climate but we also want to see how they compete with weeds and the amount of
water that they require. We allowed the legumes to grow into the spring and
just recently scythed them down and dug the pockets into which Quinoa was
planted.

The
method that we followed in planning this system of growing is described in The One-Straw
Revolution, written by Masanobu Fukuota. It is a method that he refers to
as the “Do Nothing Method” or “Natural Farming” which is outlined in four
principles: No Cultivation, No Chemical Fertilizer or Prepared Compost, No
Weeding by Tillage or Herbicides, and No Dependence upon Chemicals. By this
method, pockets of annual grains are inter-planted among an under story of
perennial legumes, in our case White Clover and Alfalfa. The legumes fix
nitrogen and carbon and compete with weeds, in addition to retaining water,
while the annual grains, in our case Quinoa, provide calorie rich seeds for
consumption and biomass for soil sustainability. This technique uses a no till
approach, and minimal human interference. The seed florets are removed from the
annual grains by hand; the stalks are scythed and left in place to decompose
and return carbon to the soil. By leaving the biomass in place we promote
nutrient cycling without the laborious task of hauling material back and forth
from compost piles.

Living
mulch can offer a number of benefits that straw mulch cannot. Bare soil
resulting from intensive tillage can lead to soil erosion, nutrient losses, and
offsite movement of pesticides. In addition, weeds can germinate and grow
without competition. Living mulches can reduce water runoff, reduces erosion,
and protect waterways from pollution. Living mulches have also been shown to
increase the population of organisms which are natural enemies of some crop
pests.

As
atmospheric CO2 levels rise and the effects of increased greenhouse
gases result in higher global temperatures, the application of living mulches for
carbon fixation also becomes more appealing.