Blog assignment 3: methods
and organisation
Tree nursery Schinznach –Which measurement methods
will be applicated? How can the measurements be coordinated?
Based on the earlier blogs and a group session we decided, which
parameters should be measured in our project week and who will undertake which
measurements. To give a short overview, the main data to evaluate is listed
here:
Parameter
|
Measurement method
|
requirements
|
responsible
|
precipitation (litres/m2)
|
quantity / meteo data
|
precipitation gauge/meteo data
|
Zoë
|
irrigation (litres)
|
Nursery data
/ flow meter / quantity
|
Nursery data /
flow meter /bucket, scale
|
Zoë
|
pumped pool water (litres)
|
Nursery data / flow meter
|
Nursery data / flow meter
|
Zoë
|
inflow pool (litres)
|
quantity
|
Bucket, scale
|
Sarah
|
runoff patches (litres)
|
quantity
|
Bucket, scale
|
Valerio
|
leakage foil (litres)
|
calculation
|
in-/outflow data
|
Valerio
|
leakage pool (litres)
|
calculation?
|
in-/outflow data
|
Sarah
|
soil humidity (pascal)
|
tensiometer
|
tensiometer
|
Zoë
|
Soil water content (litres)
|
calculation, weight measurements
|
tensiometer data, scale
|
Zoë
|
evapotranspiration (litres)
|
weight measurements
|
scale
|
Eline
|
interceptive evapotranspiration
(litres)
|
weight measurements/ calculation
|
?
|
Christoph
|
wind (m/s)
|
logger data
|
logger nursery
|
?
|
temperature (°C)
|
logger data
|
logger nursery
|
?
|
air humidity (%)
|
logger data
|
logger nursery
|
?
|
The measurement tasks I will undertake are particular links of the whole
water system. The exact areas to survey still need to be discussed in the group.
Material
Tensiometer (ZHAW)Scale (ZHAW / Private)
Bucket (Zulauf AG)
Flow Meter (Zulauf AG)
Weather data logger (Zulauf AG)
Precipitation gauge (Zulauf AG / ZHAW)
Software: Microsoft Excel, Meteo data at http://www.agrometeo.ch/de/meteorology/datas (private)
precipitation
For measuring the precipitation amount, a
precipitation gauge can be used. To get the rough amount of water added to the
system, the surface of the different areas and of the pond need to be
evaluated. For an interpolation, meteo data from the region can be used. (Goyal, P. 93)
irrigation
The irrigation amount per area can be determined by
flow meter. To have more detailed information about the subareas irrigated, to
be able to ascertain the amount of water brought to the specific pots, direct measurements
under the jets must be done. With this information, the whole amount of water
to the particular pots can be downscaled by knowing the irrigation amount.
pumped pool
water
Therefor flow meter data from the nursery can be
used.
soil humidity
The soil humidity needs to be investigated to be
able to calculate the amount of water stored in the soil. To determine it,
measurements with a tensiometer need to be done. (Haman & Yeager) To be able to scale it up, the
measurement has to be done every hour just as the air humidity, wind velocity
and temperature. With these parameters, it should be possible to make a very
rough estimation of the transpiration rate according to different weather
conditions.
Soil water
content
The data about soil humidity used to calculate the
unmeasurable datasets such as leakage is the quantity of water stored in the
pots. To come to know the amount of water stored in a pot, the tensiometer
values need to be aligned with the corresponding weight. A test serie needs to
be done separately, measuring the weight of the absolutely dry soil, and then
measure weight gain and the relative matric water potential in several steps
until full saturation. With this data, the calculation factor can be
determined.
Upscaling
To get significant predications about the water
balance in the nursery, the whole dataset should imply a whole year or more.
Our dataset however will only cover one week. But with the according meteodata
it will be possible to make at least rough estimations for the rest of the
year, by defining evapotranspiration rates according to temperature, wind
velocity,radiation and air humidity. (Goyal, P.95) But it is impossible to predict the differences in
growth rate by decreasing temperatures, and as long we don't have very extreme weather
conditions, our scales would be very inaccurate. To get all our data in a
common datasheet, the measurement times should be aligned.
As a first draft of our data collection sheet I
created this table. The classifications of the different
compartiments and pot types must be defined unitary before the first
measurements taken.
(Dumroese, P.194)
(Dumroese, P.194)
Table: Pattern for data
collection sheet
Literature:
M. R.
Goyal, E. W. Harmsen, Evapotranspiration: Principles and applications for water
management Apple academic Press, 2014
R.K. Dumroese et al. Nursery manual for native plants: Volume 1: Nursery management U.S. Department of agriculture, 2009
Haman, D. Z., Yeager, T. H. (No Date).
Controlling Irrigation with Tensiometer and Time Domain Reflectometry (TDR).
Final
Report.
Abgerufen
am 09.05.2016 von
http://www.nurserycropscience.info/water/system-design-and-management/efficiency/yeager-congtrolling-irrigation-with-tdr-and.pdf/view
Dear Zoe,
AntwortenLöschenI like your short overview schedule very much. It gives a great outline of the parameters who are measured and who is responsible for them. It gives also evidence on the parameters which are necessary but not assigned to a responsible yet. Unfortunately, the schedule is not always correct. As example, to measure the runoff from the irrigation events, not a bucket and a scale are required but a bucket with a rope and maybe a flowmeter.
Also your considerations about upscaling are valuable. Regrettably, I don’t agree with what you wrote in the subchapter “irrigation”: I differ from your opinion that it is necessary to do direct measurements under the jets. I don’t think that we have to know the amount of water brought to the specific pots because for our purposes we just need to know the water brought to a specific irrigation area.
According to the table you posted, you intend to make measurements on the whole tree nursery. Do you think we’ll be able to execute all these measurements? I would suggest to focus on a selection and in return be able to achieve all measurements.
Finally, I’m missing information about dependences between measurements, possible problems, plan B and the required timing of your measurements with subsequent embedding in the week schedule.
I’m sure we will resolve the mentioned details at our next group meeting.
Best regards,
Valerio