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Keyline Water Management is practiced around the world, and is promoted by farmers and farm system
designers. Promoters report improvements in soil water storage and distribution, and rapid increase in
topsoil depth. These results have typically been achieved in conjunction with other soil management
best practices and there has been little scientific evidence to support keyline plowing specifically.
The ‘Keyline Water Management: Field Research & Education in the Capital Region Project’ was started
to engage farmers and land managers in the Capital Regional District with the keyline water
management concepts. Specifically, keyline water management as a tool for farm-scale climate change
adaptation. The Soil Monitoring Program was designed as a pilot program to measure the changes in
water storage and soil quality after keyline plowing on pasture. The results of the Soil Monitoring
Program are intended to be used to determine whether Keyline plowing could be part of a wider
regional water management and climate change adaptation strategy, and evaluate methods of assessing
its use.
Our treatment/control sites were largely unused, mowed-only or seldom-grazed pastures prior to study.
We chose these conditions to be able to isolate keyline plowing from other active management
strategies and assess the benefit of keyline plowing on its own. We tested soil moisture and soil quality
metrics that we expected to show change within the two-year (two full growing seasons) project
timeframe. We installed permanent soil moisture probe arrays on two farms to collect year-round soil
moisture content on the plowed and unplowed pastures. We also collected soil organic carbon samples,
root depths and penetrometer measurements from three farms.
We found that the benefit of using a permanent soil moisture probe installation was that we were able
to collect real-time response to rainfall and constant soil conditions throughout the year. The drawbacks
were that to avoid damaging the equipment, we were not able to plow the 5-m x 10-m moisture probe
zone again after the first pass when probes were installed. It is common among practitioners to plow
progressively deeper over a three-year period, which was done on the surrounding pasture, but we
were not able to evaluate the direct effect of these repeated passes.
We also found that the active carbon analysis method we used was low cost and repeatable, and would
be useful for gathering larger datasets in the region. We worked with the B.C. Ministry of Environment &
Climate Change Strategy’s Analytical Laboratory in Victoria, BC to trial this potassium permanganate
extraction method and it was considered a successful addition to their soil testing service.
The findings of the Soil Monitoring Program were that one pass of keyline plowing:
● Did not appear to affect the rate at which soils dry out at the start of growing season.
● Did not appear to increase water infiltration rate into the soil during typical (less than 4 mm in a
24-hour period) rainfall events during the summer.
● Did not appear to affect the overall rate at which soils absorb water during the fall months.
● Did not appear to increase water infiltration into the subsoils during the winter (saturated
period between November and February).
● Did not appear to increase active carbon concentration in the topsoil on two out of three farms.
iii
● May have increased soil moisture holding capacity in the topsoil, but not the subsoil, during the
summer.
● May increase water infiltration rate during larger-than-average summer and fall rainfall events
(at least 4 mm of rain in 24 hours, or 8 mm of rain in a 36-hour period on the monitoring sites)
● May result in a sustained decrease in soil penetration resistance and increase rooting depth on
sites that have coarse soil textures, but not on sites with medium soil textures (no fine soil
textures were tested).
Our results suggest that the benefits of the plow for soil decompaction may be dependent on soil
texture, or use in combination with other soil quality improvements (e.g. compost tea injection), longer
use of the technique, or seeding directly into the rip line. Keyline plowing did appear to increase active
carbon on one farm, and total organic carbon on two of the three sites. However, a change in total
organic carbon in only two years is an unexpected result based on the literature, so it is most likely that
the apparent change in total organic carbon was because there were not enough replicates collected.
designers. Promoters report improvements in soil water storage and distribution, and rapid increase in
topsoil depth. These results have typically been achieved in conjunction with other soil management
best practices and there has been little scientific evidence to support keyline plowing specifically.
The ‘Keyline Water Management: Field Research & Education in the Capital Region Project’ was started
to engage farmers and land managers in the Capital Regional District with the keyline water
management concepts. Specifically, keyline water management as a tool for farm-scale climate change
adaptation. The Soil Monitoring Program was designed as a pilot program to measure the changes in
water storage and soil quality after keyline plowing on pasture. The results of the Soil Monitoring
Program are intended to be used to determine whether Keyline plowing could be part of a wider
regional water management and climate change adaptation strategy, and evaluate methods of assessing
its use.
Our treatment/control sites were largely unused, mowed-only or seldom-grazed pastures prior to study.
We chose these conditions to be able to isolate keyline plowing from other active management
strategies and assess the benefit of keyline plowing on its own. We tested soil moisture and soil quality
metrics that we expected to show change within the two-year (two full growing seasons) project
timeframe. We installed permanent soil moisture probe arrays on two farms to collect year-round soil
moisture content on the plowed and unplowed pastures. We also collected soil organic carbon samples,
root depths and penetrometer measurements from three farms.
We found that the benefit of using a permanent soil moisture probe installation was that we were able
to collect real-time response to rainfall and constant soil conditions throughout the year. The drawbacks
were that to avoid damaging the equipment, we were not able to plow the 5-m x 10-m moisture probe
zone again after the first pass when probes were installed. It is common among practitioners to plow
progressively deeper over a three-year period, which was done on the surrounding pasture, but we
were not able to evaluate the direct effect of these repeated passes.
We also found that the active carbon analysis method we used was low cost and repeatable, and would
be useful for gathering larger datasets in the region. We worked with the B.C. Ministry of Environment &
Climate Change Strategy’s Analytical Laboratory in Victoria, BC to trial this potassium permanganate
extraction method and it was considered a successful addition to their soil testing service.
The findings of the Soil Monitoring Program were that one pass of keyline plowing:
● Did not appear to affect the rate at which soils dry out at the start of growing season.
● Did not appear to increase water infiltration rate into the soil during typical (less than 4 mm in a
24-hour period) rainfall events during the summer.
● Did not appear to affect the overall rate at which soils absorb water during the fall months.
● Did not appear to increase water infiltration into the subsoils during the winter (saturated
period between November and February).
● Did not appear to increase active carbon concentration in the topsoil on two out of three farms.
iii
● May have increased soil moisture holding capacity in the topsoil, but not the subsoil, during the
summer.
● May increase water infiltration rate during larger-than-average summer and fall rainfall events
(at least 4 mm of rain in 24 hours, or 8 mm of rain in a 36-hour period on the monitoring sites)
● May result in a sustained decrease in soil penetration resistance and increase rooting depth on
sites that have coarse soil textures, but not on sites with medium soil textures (no fine soil
textures were tested).
Our results suggest that the benefits of the plow for soil decompaction may be dependent on soil
texture, or use in combination with other soil quality improvements (e.g. compost tea injection), longer
use of the technique, or seeding directly into the rip line. Keyline plowing did appear to increase active
carbon on one farm, and total organic carbon on two of the three sites. However, a change in total
organic carbon in only two years is an unexpected result based on the literature, so it is most likely that
the apparent change in total organic carbon was because there were not enough replicates collected.
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