SpectraCrop Plant Vitality and P-Tester User Manual
User Manual for
SpectraCrop Plant
Vitality and P-Tester
1
Table of Content
1. Terms and Conditions ............................................................................ 3
2. Introduction ........................................................................................... 4
3. SpectraCrop Plant Vitality and P-Tester ................................................. 6
3.1 Flow Chart ......................................................................................... 6
4. How to Perform a Measurement ........................................................... 8
5. The SpectraCrop App ........................................................................... 10
5.1 New ................................................................................................. 10
5.2 List .................................................................................................. 13
5.3 Map ................................................................................................. 18
5.4 User ................................................................................................ 19
6. How to Use the P-tester ....................................................................... 21
2
1. Terms and Conditions
The Plant Vitality and P-Tester is a complicated apparatus using sophisticated algorithms to predict
the vitality and P status of plants. Correct interpretation of results requires knowledge to the
possibilities and limitations of the technique.
The P-tester is introduced on the market in a tightly controlled program running in the growing
seasons of 2017-18 and 2018-19, where only a limited number of devices are offered to selected
users. Implementation of a trial and introduction period allows the team behind SpectraCrop to
adapt and improve hardware and algorithms behind the P-tester under variable field conditions
and in different crop and plant species, for the benefit of all future users.
Purchase of the instrument is therefor offered under the following conditions:
1. Use of the instrument must happen in accordance with the user manual and users must be
aware of the limitations of the technique.
2. Data obtained by the P-tester are automatically stored on a server owned by SpectraCrop.
To aid in future development and upgrades of hardware and algorithms, users agree that
all collected data are available to SpectraCrop. Data will not be handed over to any third-
party by SpectraCrop.
3. SpectraCrop cannot guarantee the accuracy of the measurements and cannot be held
responsible for any errors or losses occurring as a result of measurements, obtained by the
P-tester.
4. SpectraCrop cannot guarantee full functionality of the cloud server and users must accept
that down-time periods might occur.
5. Users agree that publication of any result in any format obtained by the P-tester must be
approved by SpectraCrop during the trial and introduction period running until the end of
the growing season 2019 (31/9-2019). Guidance in use and in interpretation of data during
that period is offered as a free service.
3
2. Introduction
A
B
Congratulations on your new Plant Vitality and P-Tester from SpectraCrop. With the P-tester, you
can perform measurements on plants directly in the field, and in seconds determine whether the P
nutritional status is adequate. The handheld device transmits the readings directly to your
smartphone (iPhone). With the use of easily understandable graphics, you get instant answers on
essential plant vitality parameters including a P diagnose.
The P-tester records chlorophyll a fluorescence which reflects the efficiency of the electron
transport in photosynthesis. Based on the course of these fluorescence transients, important
information is revealed on general plant vitality and P status (Figure 1).
Figure 1: A: A normal chlorophyll a fluorescence transient from a healthy plant. B: A fluorescence transient from a healthy control
and a P deficient plant. Note that the x-axis is on a logarithmic scale.
The chlorophyll a fluorescence transient is also known as an OJIP curve, where base-line
fluorescence is known as “O”, the two intermediate steps are named “J” and “I” and maximum
fluorescence is called “P”. A healthy plant will always reveal a transient similar the one in Figure
1A. Every reading is visualized in the SpectraCrop app, and any deviations from the healthy
fluorescence transient indicate plant stress.
In addition to commonly used plant vitality measures, the P-tester estimates the bioactive pool of
P in the biophysical processes of photosynthesis. Phosphorus has a very important function in the
formation of ATP, which is used in the cascades of biochemical processes that fix CO2 from the air
and convert it into carbohydrates. If P is not present in optimal concentration, key processes in
4
photosynthesis are affected, and so in-turn is the OJIP curve. Identifying this effect in the OJIP
curve is what allows the P-tester to specifically, and sensitively, measure the nutritional P-status of
a plant. In Figure 1B the fluorescence transient of a healthy control plant and a P deficient plant is
illustrated. It is evident that at the so called “I-step” the two curves are easy distinguishable. It is
based on the deviations within this area, that the P-tester is calculating the P status of the plant.
As the process of photosynthesis is the same for all higher plants, there is no need for correction
and calibration in order to adapt the reading to a specific plant species.
For further informations regarding the scientific approach used in this device see “Frydenvang et
al. (2015): Sensitive detection of phosphorus deficiency in plants using chlorophyll a fluorescence.
Plant Physiology, Breakthrough Technologies, vol. 169, pages 353-361”.
5
3. SpectraCrop Plant Vitality and P-Tester
The SpectraCrop Plant Vitality and P-Tester is accompanied with a handy suitcase which includes
the following items: Handheld P-tester, 10 leaf clips to dark adapt leaves prior to measurements
and 1 power plug (EC standard; Figure 2).
Figure 2: The P-tester is accompanied with a handy suitcase.
3.1 Flow Chart
The flow of data after a measurement with the P-tester is presented in Figure 3. Leaf
measurements are transferred via Bluetooth to the SpectraCrop app on your Iphone, where four
plant vitality parameters immediately are present. The P-diagnose is calculated on an external
server, and will first be available when the data has been sent and received via the app. Note that
your phone must send and receive data to obtain the P-diagnose.
6
Figure 3: Flow chart of the use of the P-tester. Bluetooth connection ensures transfer of the measurements to the SpectraCrop app,
whereas the phone must send and receive data to obtain the P-diagnose from the external server.
7
Loading...