Water infiltration
What is it?
and ruler to measure how quickly the water soaks
into the ground in six minutes. Multiply by 10 to
estimate the infiltration rate in millimetres per
hour. Score the result using the Water Infiltration
Score system and complete the Bullseye Score
Card.
Infiltration measures how readily water enters
the soil through the surface. It shows how quickly
rainfall will enter the soil and how much will run
off.
Why it is important:
Measuring method:
The more rainfall that enters the soil profile, the
more will be available for plant growth. So it
is important that as much water enters the soil
during each rainfall event as possible for that land
type. High levels of runoff lead to erosion and
gully formation. The infiltration capacity of soil is
related to its texture, structure and pasture cover
levels. For any given soil type, the better the
structure, the better the infiltration. This results
in more plant-available water for pasture growth
through the year.
At a minimum, water infiltration can be assessed
at one point along your transect. Walk 15 paces
along the transect and use this point to conduct
the test. If the monitoring point has a high
tussock grass, or shrub, conduct the test directly
adjacent to the plant. If the plant is low to the
ground, cut it off close to ground level and test
at that point. Be consistent. Note if the test was
carried out over, or adjacent to, a plant to ensure
consistency the following year.
For more accurate monitoring, conduct the test
three times along the transect and calculate an
average. Walk along the transect and stop every
seven paces to conduct the test.
How to assess it:
Infiltration is measured by pouring a volume of
water into an infiltrometer ring (a piece of PVC
or steel pipe about 120 to 200mm in diameter)
hammered partially into the ground.
Equipment:
Hardwood board, mallet or small sledge hammer,
infiltrometer ring, ruler, stopwatch or smartphone,
shears,10L bucket, a few litres of water.
Where possible, pour the water gently onto
an open hand, through cheesecloth, or onto a
sponge into the infiltrometer. Use a stopwatch
Scoring the Water Infiltration Rate
Score results using the table below:
Results mm/hr 0 to 25 25 to 10 100 to 250 More than 250
Scoring guide Poor Moderate Good Very good
Score 0 1 2 3
Write the infiltration rate score on the Bullseye Score Card and fill in the bullseye. If three tests
were conducted, use the average score.
14 - RASH MANUAL