In the
most recent edition of the “Dirt
First Conversation Series”
hosted by the Ecological Farming Association, four experienced and
innovative organic farmers reported on their progress after two years
of field trials in no-till organic, commercial-scale vegetable
production. They are experimental and forward thinking, taking risks
to pilot new ways of growing California row crops without tillage
while maintaining or even increasing yields.
The four
farmers represent a diversity of crops, geographies and growing
practices. Phil Foster of Phil Foster Ranches
has 250 acres of organic fruit and vegetables near San Juan Bautista
and Hollister. Paul Muller of Full Belly Farm
in Capay Valley grows 400 acres with 80 different crops and livestock
as an integral part of the system. Scott Park of Park Farming Organics
has 1700 organic acres in the Sacramento Valley where he produces
10-20 different crops including processing tomatoes, grains, beans and
vegetables. Tom Willey of T&D Willey Farms
previously farmed 75 acres in Madera, California and currently
consults with other farmers on no-till practices.
What is no-till?
The large majority of specialty
crop growers in California till their fields to eliminate weeds and
loosen up the soil in preparation for planting. On organic farms,
without the use of chemical herbicides, tilling is the predominant
weed control method. However, tilling disrupts the soil structure and
microbiological life and is a contributor to releasing soil carbon
into the atmosphere, thereby contributing to climate change. Without
healthy soil fungi and bacteria that provide plant nutrients, farmers
rely more on external inputs like chemical fertilizers. Also, soils
disturbed with tilling often retain less water, a consideration for
California growers facing yetanother dry summer.
The goal of reduced-till or no-till farming systems is to minimize
soil disturbance while implementing alternatives practices that
control weeds, provide ground cover and maintain yields.
Cover
crops are a powerful tool in the toolbox—they are grown between cash
crop rotations to provide soil nutrients, soil cover to limit weed
growth, and can serve as a mulch and source of organic matter if left
on the field to decompose when the next crops are planted. The farmers
involved in this trial are experimenting in real-world situations with
strategies such as cover crops and crop rotation. The challenge that
follows is how to abate competition before planting a cash crop.
Organic strategies to remove cover
crops and weeds before planting cash crops include:
Undercutting: cutting the cover crop roots below the soil surface
without tilling
Roller
crimpers: Equipment that cuts down cover crops and leaves them on
the field to decompose as a mulch
Flaming:
burning that kills grass, but not broadleaf crops
Occultation: cover beds with black tarp to kill weeds and break down
crop residue
Plasticulture: plastic covering on beds
Paul
Muller of Full Belly Farms likened the no-till strategies to creating
an “armor” for soil that keeps the surface covered, helps retain
moisture for the microorganisms and pushes living roots of cover crops
below the surface where they promote an essential balance of bacteria
and fungi in the soil. This balance has been shown to improve yields.
Both Paul and Scott Park emphasized that these practices are an
investment in the long-term health of our agricultural lands versus
the conventional farming model that maximizes short-term financial
returns.
Promising
findings and more trials ahead
The major success highlighted in
this webinar was the significant yield and nutrient improvements
observed in a no-till, plasticulture watermelon trial compared
side-by-side to a control bed with reduced till at Phil Foster
Ranches.
The plasticulture treatment
resulted in higher soil moisture, temperature and nutrient
availability (see Fig. 1). The results are significant because this is
only one of two studies that have shown equal or greater yields
in no-till systems compared to some or full tillage (see Fig. 2). The
farmers intend to expand this trial next year.
Though this trial appears to be a
step forward, Scott Park emphasized how context-dependent no-till
farming is after growing cover crops in his system for 32 years and,
in his own words, “spending a lot of time figuring out how to do
things wrong.”
Figure 2: Higher yields shown in trial #1
and 2 in no-till compared to reduced-till
Ultimately, he has developed an effective cover cropping system with
rice, vetch and wheat that significantly reduces tillage and increases
soil carbon compared to the conventional model. This season he will
run trials on grazing, multi-species and cash crops.
After
farming for decades, these growers have immersed themselves in
learning new ways to farm and are blazing the way in our understanding
of climate-smart farming.
Be sure
to catch future conversations in EcoFarm’s Dirt First series, and
especiallyDigging into the Research of
Small-Scale No-Till Farming Systems,
which will cover the latest research in small-scale, intensive,
minimal-disturbance, ecological farming systems.
