JP3908870B2 - Fertilizer application method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for determining whether or not the amount of fertilizer applied to a sample is appropriate.
[0002]
[Prior art]
In tea farms and the like, a large amount of fertilizer is applied in order to increase umami compared to other crops. However, if fertilizer is applied excessively, troubles such as delayed growth of shoots and withering of roots occur. Moreover, the acidification of nitric acid in rivers and groundwater can be induced, and excessive fertilization has also caused environmental problems.
[0003]
As a method for determining the amount of fertilization to prevent such excessive fertilization, conventionally, there are a method of collecting soil and analyzing the fertilizer concentration, and a method of digging up the soil and visually determining the state of the roots. Are known.
[0004]
[Problems to be solved by the invention]
However, with the former method, not only the observation on the spot is not possible, but also it depends greatly on the environment such as the number of days after fertilization and rainwater, so accurately determine whether the fertilization amount is within the appropriate range It ’s difficult. Further, in the latter method, it is often possible to grasp visually only after symptoms such as root death occur due to excessive fertilization, and it tends to be too late to recover the sample. For this reason, as in the former method, it is difficult to accurately determine the amount of fertilization.
[0005]
The present invention has been made in view of such circumstances, and an object thereof is to provide a fertilization amount determination method capable of accurately determining whether or not the fertilization amount is appropriate.
[0006]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the present invention provides a fertilizer application amount determination method for determining whether or not the amount of fertilizer applied to a sample is within a predetermined range, and the excitation light is applied to the sample subjected to fertilizer. A step of detecting delayed fluorescence generated from a sample irradiated with excitation light for a predetermined time, a step of calculating attenuation data that is a relationship between the detection time of delayed fluorescence and the emission intensity of delayed fluorescence, The method includes a step of obtaining a fertilization amount determination value based on the attenuation data, and a step of determining whether the fertilization amount determination value is within a predetermined range.
[0007]
According to the fertilization amount determination method according to the present invention, first, excitation light is irradiated toward a sample such as a leaf of a plant to which fertilizer has been applied. Then, delayed fluorescence is generated from the leaves of the plant. Such delayed fluorescence is emitted once again as light energy after a certain delay time after the excitation light is once converted into chemical energy inside the chloroplast, and if such delayed fluorescence is monitored, It is possible to obtain not only so-called superficial information but also information on the molecule receiving the chemical energy, that is, internal information.
[0008]
Delayed fluorescence generated from the sample is detected for a predetermined time by a photodetector such as a photomultiplier tube. Thereafter, attenuation data that is the relationship between the detection time of delayed fluorescence and the emission intensity of delayed fluorescence is calculated, and a fertilizer application determination value is obtained based on this attenuation data. Then, it is determined whether or not the fertilization amount determination value is within a predetermined range, and thus whether or not the fertilization amount to the sample is within a predetermined range. Here, if the allowable range is determined based on the fertilizer application amount determination value when the fertilizer application amount is appropriate, it can be determined whether or not the amount of fertilizer applied to the sample is appropriate.
[0009]
In the fertilizer application determination device of the present invention, it is desirable that the fertilizer application determination value is a value of a ratio of two slopes of an attenuation curve created based on the attenuation data.
[0010]
In this case, for example, when the slope of the decay curve in the early detection of delayed fluorescence is k1, and the slope of the decay curve in the latter detection period is k2, the value of k2 / k1 or k1 / k2 becomes the fertilizer application amount determination value. As a result of intensive studies by the present inventors, it has been found that the fertilization amount judgment value indicated by k2 / k1 or the like has a certain relationship with the amount of fertilizer applied to the sample. Therefore, the fertilizer application amount judgment value such as when the fertilizer application amount is appropriate or when the sample withered too much is accumulated as data in advance, and the allowable range of the fertilizer application judgment value can be determined based on this data it can.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, with reference to an accompanying drawing, a suitable embodiment of a fertilization amount judging method concerning the present invention is described in detail. In addition, the same code | symbol shall be used for the same element and the overlapping description is abbreviate | omitted.
[0012]
FIG. 1 is a configuration diagram of a fertilization amount determination device 2 used in the fertilization amount determination method of the present embodiment. The fertilizer application determination device 2 includes a delayed fluorescence measurement device 4, a determination device 6 connected to the delayed fluorescence measurement device 4 via a cable 10, and a display 8. The delayed fluorescence measurement device 4 is a portable device that can be detached from the determination device 6.
[0013]
First, the configuration of the delayed fluorescence measurement device 4 will be described. The delayed fluorescence measurement device 4 is provided with a sample setting unit 14 configured to have a clip shape that can hold the sample 12 and to block external light. In the present embodiment, tea leaves are used as the sample 12.
[0014]
In this embodiment, a photomultiplier tube (PMT) 16 is used as a photodetector for detecting delayed fluorescence. Light from the outside is interposed between the photomultiplier tube 16 and the sample setting unit 14. A substantially cylindrical delayed fluorescence passage portion 18 that can be blocked is formed. The photomultiplier tube 16 is equipped with a multi-alkali photocathode and can detect light having a delayed fluorescence wavelength of 720 to 760 nm from its spectral sensitivity characteristics.
[0015]
A laser diode (LD) 20 that is a light source of excitation light for exciting the sample 12 is disposed in the vicinity of the sample setting unit 14 in the delayed fluorescence passage unit 18. The laser light emitted from the laser diode 20 has a wavelength of 680 nm, and the intensity of the laser light at the irradiation position of the sample 12 is 10 mW / cm ² . In addition, a shutter 22, a condensing lens 24, and a filter 26 are disposed in the delayed fluorescence passage unit 18 in order from the sample setting unit 14 side. A f50 1: 1 relay lens is used as the condensing lens 24, and a cut-off filter that cuts light having a wavelength shorter than 720 nm is used as the filter 26.
[0016]
Further, on the left side of the photomultiplier tube 16 in FIG. 1, a control device that controls lighting and extinguishing of the LD 20, opening and closing of the shutter 22, opening and closing time of the delayed fluorescence by the photomultiplier tube 16, etc. 30 is arranged. Further, in the vicinity of the control device 30, a battery 32 which is a drive source for the photomultiplier tube 16, the LD 20 and the shutter 22 is replaceably disposed.
[0017]
Next, the configuration of the determination device 6 and the display 8 connected to the delayed fluorescence measurement device 4 will be described using the block diagram of FIG. As shown in FIG. 2, the determination device 6 includes a preamplifier 34 that amplifies a signal from the photomultiplier tube 16 in the delayed fluorescence measurement device 4, a counter 36 that counts the amplified signal, and an attenuation. CPU 40 that performs calculation of a curve, calculation of fertilization amount determination value, determination of whether or not the calculated fertilization amount determination value is within an allowable range (predetermined range), and a plurality of allowable ranges of fertilization amount determination values described later in detail An allowable range data storage unit 38 previously stored for the fertilizer is incorporated. The CPU 40 is connected to a display 8 that can display an attenuation curve, a fertilization amount determination value, a determination result, and the like.
[0018]
Here, a general attenuation curve will be described with reference to FIG. FIG. 3 is a graph in which the horizontal axis represents the detection time of delayed fluorescence and the vertical axis represents the emission intensity of delayed fluorescence, and the curve shown in this figure is an attenuation curve. Here, tea leaves collected from farmland where the amount of fertilizer is appropriate (nitrogen component is about 50 kg / 10a per year) (round mark), tea leaves A collected from farmland where fertilizer is excessive (about 70 kg / 10a per year) (square mark) 4 types of tea leaves B (triangular marks) collected from farmland with excessive fertilizer (approximately 80 kg / 10a per year) and tea leaves C (cross marks) collected from agricultural land with excessive fertilizer (approximately 100 kg / 10a per year) Used. In order to prevent variation in measurement, 33 tea leaves were randomly collected from several trees for each field.
[0019]
Regarding the tea leaves C, the effect of excessive fertilizer cannot be determined by observing the portion appearing on the ground, but when digging up the soil and observing the roots, it was found that damage due to excessive fertilizer began to occur. Moreover, tea leaves A and B were not able to judge the influence of a fertilizer on appearance. In addition, FIG. 3 shows that the sum total of the amount of light emission of delayed fluorescence decreases as the fertilization amount increases.
[0020]
FIG. 4 calculates the attenuation rate (slope) k1 of 1 to 10 seconds after the excitation light blocking of the attenuation curve shown in FIG. 3 and the attenuation rate (slope) k2 after 15 to 40 seconds, and these are two-dimensionally mapped. It is a graph. For tea leaves A to C with excessive fertilizer, it can be seen that the initial attenuation is slower than the distribution of k1, and the late attenuation rate is larger than the distribution of k2, compared to when the amount of fertilizer is appropriate. . In particular, with regard to tea leaf C (cross mark) with the largest amount of fertilization, the late decay rate is extremely large compared to when the amount of fertilization is appropriate. The positions of the two points on the attenuation curve for obtaining k1 and k2 can be changed as appropriate.
[0021]
From k1 and k2 obtained in FIG. 4, the present inventors found that the value of k1 / k2 is related to the amount of fertilizer applied to the sample, and decided to call that value the fertilizer amount judgment value. FIG. 5 shows the fertilization amount determination value as a histogram. The horizontal axis is the fertilization amount judgment value, and the vertical axis is the frequency. From FIG. 5, it can be seen that the average value of the fertilizer application determination value decreases as the fertilizer becomes excessive. At this time, for example, by setting the allowable range of the fertilization amount determination value to 5.00 or more, the fertilization amount is determined to be appropriate when the fertilization amount determination value is 5.00 or more, and is smaller than 5.00 It can be determined that there is too much fertilizer. In addition, if the allowable range is set to 4.5 or more, it can be determined that the root is damaged like the tea leaf C when the fertilization amount determination value is smaller than 4.5. These allowable ranges can be used when the same tea leaves and fertilizer used in this experiment are used. Further, data regarding such an allowable range is accumulated in the allowable range data storage unit 38 of the determination device 6.
[0022]
Next, a method for determining whether or not the amount of fertilization is appropriate will be described.
[0023]
First, with reference to FIG. 1, the process up to the detection of delayed fluorescence will be described. First, after setting the sample 12 for which the fertilization amount is to be determined in the sample setting unit 14, the sample 12 is left in a light-shielded state for about 2 minutes. Thereafter, when the operator turns on the drive switch 28, the LD 20 is lit for about 30 seconds with the shutter 22 closed, and the sample 12 is photoexcited. After the 30 seconds of light excitation, the control device 30 opens the shutter 22 and simultaneously turns off the power supply to the LD 20. After the LD 20 is turned off, delayed fluorescence is generated from the sample 12. The delayed fluorescence passes through the shutter 22, is collected by the condenser lens 24, and reaches the photomultiplier tube 16. At this time, the filter 26 blocks light having a wavelength shorter than 720 nm. Under the instruction of the control device 30, the photomultiplier tube 16 measures 200 time sampling 200 times, that is, a change with time of about 40 seconds.
[0024]
Subsequently, referring to FIGS. 2 and 6, the control procedure of the CPU 40 built in the determination device 6 from the readout of the delayed fluorescence detected by the photomultiplier tube 16 to the display of the determination result of the fertilizer application amount will be described. To do. After the photomultiplier tube 16 detects delayed fluorescence for a predetermined time, the CPU 40 reads delayed fluorescence data, which is an electrical signal of delayed fluorescence, from the photomultiplier tube 16 (S101). The delayed fluorescence data read from the photomultiplier tube 16 is amplified by the preamplifier 34, and the amplified delayed fluorescence data is counted by the counter 36. Subsequently, the CPU 40 calculates an attenuation curve indicating the relationship between the detection time of delayed fluorescence and the emission intensity based on the count value of the delayed fluorescence data (S102).
[0025]
After calculating the attenuation curve, the CPU 40 calculates a fertilizer application amount determination value (S103). In the present embodiment, as described above, the CPU 40 obtains the slope k1 after the start of detection of delayed fluorescence 1 to 10 seconds and the slope k2 after the start of detection 15 to 40 seconds, and the value of k1 / k2 that is a fertilizer amount determination value. Is calculated. Actually, an average value of determination values obtained from several samples is calculated. After calculating the fertilizer application amount determination value, the CPU 40 reads data relating to the allowable range of the fertilizer application amount determination value from the allowable range data storage unit 38 (S104).
[0026]
Then, the CPU 40 determines whether or not the fertilization amount to the sample 12 is appropriate by determining whether or not the fertilization amount determination value exceeds the allowable range (S105). In addition, as described above, when the fertilization amount determination value is within the allowable range, the fertilization amount is determined to be appropriate, and when the fertilization amount determination value is smaller than the lower limit of the allowable range, the fertilization amount is excessive. Determined. In this embodiment, it is not necessary to set an upper limit of the allowable range because only an excessive amount of fertilizer is determined and not determined if it is too small. However, if the upper limit of the allowable range, that is, the allowable value when the amount of fertilization is too small is determined, it is possible to prevent the fertilization amount from being too small. Moreover, the tolerance | permissible_range of a fertilizer application amount judgment value can be changed suitably.
[0027]
After determining the fertilizer amount, a display command for the attenuation curve, fertilizer amount determination value, and fertilizer amount determination result is sent to the display 8 (S106), and the control operation of the CPU 40 ends. The determination result of the fertilization amount displayed on the display 8 can be used as a reference when, for example, controlling excessive fertilization or determining the subsequent fertilization amount.
[0028]
According to the fertilizer application amount determination device 2 of the present embodiment, the fertilizer application amount can be easily determined at the site where the sample is present, and since the delayed fluorescence emitted from the sample is used, the internal information of the sample is obtained. Compared to the case of visual observation or the like, it is possible to know accurately. For this reason, the fertilization amount can be determined easily with high accuracy.
[0029]
Although the invention made by the present inventor has been specifically described based on the embodiment, the present invention is not limited to the above embodiment. For example, the determination unit and the display may be incorporated in the delayed fluorescence measurement device. In this case, use on the site such as farmland becomes easier. Furthermore, even if the fertilization amount determination value is not k1 / k2 but k2 / k1, the fertilization amount can be determined.
[0030]
【The invention's effect】
As described above, according to the fertilization amount determination method according to the present invention, after detecting the delayed fluorescence emitted from the sample for a predetermined time, attenuation data that is the relationship between the detection time of the delayed fluorescence and the emission intensity of the delayed fluorescence. Is calculated, and a fertilization amount determination value is obtained based on the attenuation data. Then, it is determined whether or not the fertilization amount determination value is within an allowable range obtained in advance, and thus whether or not the fertilization amount to the sample is within a predetermined range. Here, if the said tolerance | permissible_range is defined based on the fertilizer application amount determination value when an amount of fertilizer is appropriate, it can be determined whether the quantity of the fertilizer applied to the sample is appropriate.
[0031]
Here, in the present invention, since delayed fluorescence emitted from the sample is used, not only superficial information but also information inside the sample can be obtained. For this reason, it is possible to accurately determine whether the amount of fertilization is appropriate.
[Brief description of the drawings]
FIG. 1 is a diagram showing a fertilizer application determination device used in a fertilizer application determination method of the present invention.
FIG. 2 is a block diagram showing in detail the configuration of a determination unit of the fertilizer application amount determination device.
FIG. 3 is a graph showing an attenuation curve obtained based on a sample with an appropriate amount of fertilization and a sample with an excessive amount of fertilization.
4 is a graph obtained by two-dimensional mapping of k1 and k2 values obtained from the attenuation curve shown in FIG.
FIG. 5 is a histogram showing fertilization amount determination values obtained from the attenuation curve shown in FIG. 3;
FIG. 6 is a flowchart illustrating a control procedure of a CPU of a determination unit.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 2 ... Fertilization amount determination apparatus, 4 ... Delay fluorescence measuring apparatus, 6 ... Determination apparatus, 12 ... Sample, 14 ... Sample setting part, 16 ... Photomultiplier tube, 20 ... Laser diode, 22 ... Shutter, 24 ... Condensing lens , 26 ... filter, 28 ... drive switch, 30 ... control device, 32 ... battery, 34 ... preamplifier, 36 ... counter, 38 ... tolerance range data storage unit.

Claims (2)

A fertilizer application determination method for determining whether the amount of fertilizer applied to a sample is within a predetermined range,
Irradiating the sample to which the fertilizer has been applied with excitation light;
Detecting delayed fluorescence generated from the sample irradiated with the excitation light for a predetermined time;
Calculating attenuation data which is a relationship between the detection time of the delayed fluorescence and the emission intensity of the delayed fluorescence;
Obtaining a fertilizer amount determination value based on the attenuation data;
A step of determining whether or not the fertilization amount determination value is within a predetermined range;
A fertilization amount determination method comprising: The fertilization amount determination method according to claim 1, wherein the fertilization amount determination value is a value of a ratio of two slopes of an attenuation curve created based on the attenuation data.

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