Konica SPAD-502 User Manual

CHLOROPHYLL METER
SPAD-502
A lightweight handheld meter for measuring the chlorophyll content of leaves without causing damage to plants.
The SPAD-502 is a compact meter designed to help users improve crop quality and increase crop yield by providing an indication of the amount of chlorophyll present in plant leaves. The chlorophyll content of plant leaves is related to the
Features
Compact and lightweight for portability
The SPAD-502 is small enough to fit in a pocket and is extremely lightweight (only 225g) so it can be easily taken anywhere.
Quick, easy measurements
Water-resistant
The SPAD-502 is water-resistant, so it can be used outside even in the rain. *It is not immersible, and should not be cleaned with water.
Low power consumption
The SPAD-502 uses LED light sources, resulting in extremely low power consumption. One set of two AA-size alkaline-manganese batteries can provide approximately 20,000 measurements.
condition of the plant, and thus can be used to determine when additional fertilizer is necessary. By optimizing nutrient conditions, healthier plants can be grown, resulting in a larger crop yield of higher quality.
Small measuring area
The measuring area is only 2 × 3mm, allowing measurements of even small leaves. A sliding depth stop is included for accurate positioning of sample leaves.
High accuracy
High measuring accuracy (± 1.0 SPAD unit for rice-plant leaves) allows close examination of growing conditions.
Data memory
The SPAD-502 has memory space for 30 measurements. Data in memory can be recalled or deleted at a later time, and the average value of all data in memory can be automatically calculated.
Reading checker
A reading checker enables users to check that the SPAD­502 is functioning correctly and providing accurate readings.
Theory
The SPAD-502 determines the relative amount of chlorophyll present by measuring the absorbance of the leaf in two wavelength regions. The graph at right shows the spectral absorbance of chlorophyll extracted from two leaf samples using 80% acetone. From the diagram, it can be seen that chlorophyll has absorbance peaks in the blue (400-500nm) and red (600-700nm) regions, with no transmittance in the near-infrared region. To take advantage of this characteristic of chlorophyll, the SPAD-502 measures the absorbances of the leaf in the red and near-infrared regions. Using these two transmittances, the meter calculates a numerical SPAD value which is proportional to the amount of chlorophyll present in the leaf.
Applications
3.5 y =0.079 x - 0.154
***
r =0.908
3.3
3.1
2.9
2.7
2.5
2.3
2.1
1.9
Leaf-blade nitrogen concentration
1.7
Checking the nutritional condition of plants
The chlorophyll present in the plant leaves is closely related to the nutritional condition of the plant. As can be seen from the graph below, the chlorophyll content (represented by the measured SPAD value) will increase in proportion to the amount of nitrogen (an important plant nutrient) present in the leaf. For a particular plant species, a higher SPAD value indicates a healthier plant.
n =68
1984 1985
24 26 28 30 32 34 36 38 40 42
Measured SPAD value
A
B
Trancemittance
Ultra­violet
Measured SPAD value
Days before fully formed ears appear
Date(month.day)
400 500
Wavelength Infrared
40
35
Ear differentlation period
30
25
9.1 9.5 10.3 10.8 12.5 13.0
7.1 7.10 7.20 7.30
Sasanishiki rice plant development
Young ear formation period
35
Young ear growth line
(1mm)
30 25 20 15 10 5
600 700(nm)
Ear fertility
(8cm)
Bursting period
(3mm)
(16 -18cm)
Fully formed ears appear
Determining when additional fertilizer is necessary
A decrease in the SPAD value indicates a decrease in the chlorophyll content and nitrogen concentration. This decrease may be due to a lack of nitrogen available in the soil. This problem can be solved by adding fertilizer to the soil. For example, it was determined from past experience that for Sasanishiki rice plants a SPAD value of 35 or above was desirable to produce a target yield of 600kg/10a. During the differentiation and formation of ears, a period of rapid plant development, the SPAD value fell to between 29 and 32, indicating that additional fertilizer was necessary.
0
8.14
SPECIFICATIONS
Type: Handheld meter for measuring chlorophyll using optical density difference at two wavelengths
Measurement sample: Crop leaves Measurement system: Optical density difference at two wavelengths Measurement area: 2 × 3mm Light source: 2 LEDs (light-emitting diodes) Receptor: 1 SPD (silicon photodiode) Display: Measurement data: 3-digit LCD with decimal point
Data number: 2-digit LCD
Data memory: Space for 30 data sets Controls: Power switch, AVERAGE key, ALL DATA DELETE key,
ONE DATA DELETE key, and DATA RECALL key
Power source: 2 AA-size alkaline-manganese (1.5V) batteries
Battery line: More than 20,000 measurements Minimum interval between measurements: Less than 2 seconds Accuracy: Within ± 1.0 SPAD unit (at room conditions, SPAD value
between 0 and 50)
Repeatability: Within ± 0.3 SPAD units (SPAD value between 0 and 50) Reproducibility: Within ± 0.5 SPAD units (SPAD value between
0 and 50)
Temperature drift: Less than ± 0.4 SPAD units/°C Temperature range: Operation: 0 to 50°C; Storage: - 20 to +55°C Dimensions: 164 ×78 × 49mm (6-7/16 × 3-1/16 × 1-15/16 in.) Weight: 225g (7-15/16 oz.) (not including batteries) Other: Warning buzzer; User calibration function
Specification subject to change without notice
2003 KONICA MINOLTA SENSING, INC.
AHIDPK
13
Printed in Japan9242-4817-41
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