Information providing device and information providing method

Abstract

To enable additional fertilization in a more appropriate manner based on the results of research.SOLUTION: An information provision device 1 comprises: a sunlight-related value magnitude discriminating unit 13 that, regarding a sunlight-related value, which is an indicator of the magnitude of sunlight, determines the magnitude of a sunlight-related value for a given period of time prior to the earing stage; and an information providing unit 10 that recommends a first additional fertilization to be applied between a time point of 35 days before the earing stage and a time point of 15 days before the earing stage if the sunlight-related value is high.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an information providing device and an information providing method for providing information on top dressing for a farm field. [Background technology]

[0002] Conventionally, after rice plants are transplanted into a field, top dressing called panicle fertilization may be applied during the period from around the panicle formation stage to around the heading stage. Patent Document 1 describes a technology for this top dressing in which the growth status is managed using a top dressing map created based on growth status information for each mesh, and the amount of fertilizer to be applied is set taking the growth status into consideration. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-003048 Summary of the Invention [Problem to be solved by the invention]

[0004] Top dressing affects the growth of agricultural crops and ultimately the condition of the harvest (quality, yield, etc.). Therefore, when research results are available regarding top dressing, there is a need to utilize those results to enable more appropriate methods.

[0005] The present invention has been made to solve such problems, and aims to enable top dressing to be applied in a more appropriate manner based on the results of research. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems, the present invention provides the following sunlight-related values ​​that are indices of the amount of sunlight: The amount of a first sunlight-related value, which is an indicator of the amount of sunlight for the target period from a reference point 30 days before the heading period to the heading period, is determined, and the amount of a second sunlight-related value, which is an indicator of the amount of sunlight for the transplanting period from the transplanting period to a specified time before 30 days before the heading period, is determined. The present invention provides information recommending that the first top dressing be applied at an early stage in the period from a reference point 35 days before the heading date to a reference point 15 days before the heading date when the first sunlight-related value is determined to be high and the sunlight-related value high / low discrimination unit determines that the second sunlight-related value is high; provides information recommending that the first top dressing be applied between a reference point 35 days before the heading date and a reference point 15 days before the heading date when the first sunlight-related value is determined to be high and the sunlight-related value high / low discrimination unit determines that the second sunlight-related value is low when the present invention provides information recommending that the first top dressing be applied between a reference point 35 days before the heading date and a reference point 15 days before the heading date when the first sunlight-related value is determined to be low; and provides information recommending that the first top dressing be applied between a reference point 15 days before the heading date and a reference point 5 days after the heading date when the present invention determines that the first sunlight-related value is low. [Effects of the Invention]

[0007] As a result of research, the inventors found that if the sunlight-related value (a value that serves as an index of the amount of sunlight) during a predetermined period before the heading date is high, the condition of the harvested crop can be improved by applying the first top dressing between a reference time point of 35 days before the heading date and a reference time point of 15 days before the heading date. Based on this, the present invention configured as described above determines the level of the sunlight-related value during a predetermined period before the heading date, and provides information indicating that if the sunlight-related value is high, the first top dressing should be applied between a reference time point of 35 days before the heading date and a reference time point of 15 days before the heading date. This allows the user to obtain information regarding the timing of top dressing based on the results of the above research, and enables fertilization in a more appropriate manner based on this information. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a block diagram showing an example of a functional configuration of an information providing device according to a first embodiment of the present invention. [Figure 2] FIG. 10 is a diagram illustrating an example of an input screen. [Figure 3] FIG. 10 is a diagram showing the transition of average solar radiation. [Figure 4] FIG. 1 is a diagram showing the relationship between the time of top dressing and yield, and the relationship between the time of top dressing and the number of unhulled grains. [Figure 5] FIG. 1 is a diagram showing the relationship between the time of top dressing and yield, and the relationship between the time of top dressing and the number of unhulled grains. [Figure 6] 4 is a flowchart showing an example of the operation of the information providing device according to the first embodiment of the present invention. [Figure 7] FIG. 10 is a block diagram showing an example of the functional configuration of an information providing device according to a second embodiment of the present invention. [Figure 8] 10 is a flowchart showing an example of the operation of the information providing device according to the second embodiment of the present invention. [Figure 9] FIG. 10 is a diagram illustrating an example of an input screen. [Figure 10] 1 is a graph showing the yield in each case. [Figure 11] 10 is a graph showing the number of unhulled grains in each case. DETAILED DESCRIPTION OF THE INVENTION

[0009] First Embodiment A first embodiment of the present invention will be described below with reference to the drawings. Fig. 1 is a block diagram showing an example of the functional configuration of an information providing device 1 according to this embodiment. The information providing device 1 is a device that provides a user with useful information regarding the timing (period or timing) of top dressing (top dressing will be described in detail later) for rice cultivation. When applying top dressing, the user can refer to the information provided by the information providing device 1 to determine the timing of applying top dressing.

[0010] In this embodiment, "top dressing" means the following. That is, generally, in a certain period, after rice is transplanted from a seedbed to a field, it grows through the following stages: tillering stage → panicle formation stage → heading stage → flowering and pollination stage → full heading stage → ripening stage → maturity stage. During the period from around the panicle formation stage to around the heading stage, fertilizer called panicle fertilizer may be added at a predetermined timing for the purpose of increasing the number of grains attached to the panicle and the amount of starch packed into the grain. In this embodiment, "top dressing" means the addition of fertilizer at a predetermined timing during the period from around the panicle formation stage to around the heading stage.

[0011] As shown in FIG. 1, the information providing device 1 is connected to a display device 2 such as a liquid crystal display or an organic electroluminescence (EL) display, and an input device 3 such as a mouse or a keyboard. Also shown in FIG. 1, the information providing device 1 functionally comprises an information providing unit 10, a variety discrimination unit 11, a leaf color density discrimination unit 12, and a sunlight-related value intensity discrimination unit 13. Each of the functional blocks 10-13 can be configured using hardware, a DSP (Digital Signal Processor), or software. For example, when configured using software, each of the functional blocks 10-13 is actually configured using a computer CPU, RAM, ROM, etc., and is realized by the operation of a program stored in a recording medium such as RAM, ROM, a hard disk, or a semiconductor memory. The information providing device 1 also comprises a storage unit 14 as storage means. The above also applies to a second embodiment, which will be described later.

[0012] When the user wants the information providing device 1 to provide information regarding the timing of top dressing for a certain field, the user operates the input device 3 to instruct the display device 2 to display the following input screen 16 ( FIG. 2 ). This instruction is given, for example, at a time point earlier than "35 days before the heading date" but close to "35 days before the heading date" (for example, about 40 days before the heading date). In addition, it is generally assumed that the instruction is given at least 30 days before the heading date. The heading date is predicted based on various indicators of rice growth, past and predicted trends in the external environment that affect rice growth, and other factors. In response to the above instruction from the user, the information providing unit 10 displays the input screen 16 on the display device 2.

[0013] Fig. 2 is a diagram showing the input screen 16. As shown in Fig. 2, the input screen 16 is provided with an input field N1 for inputting the variety. The input field N1 is a pull-down menu that displays a list of selectable varieties as items, and the user selects an item indicating the variety of rice in the field from the items in the pull-down menu.

[0014] 2, the input screen 16 is provided with an input field N2 for inputting leaf color intensity (leaf color color scale). The user inputs into the input field N2 the value of leaf color intensity measured for rice in the field using a leaf color plate at a time close to the present time (for example, if the input to the input screen 16 is 40 days before the heading date, then at a time close to that time).

[0015] As shown in Fig. 2, the input screen 16 has an input field N3 for inputting a specific predicted amount of solar radiation (sunlight-related value). In this embodiment, the specific predicted amount of solar radiation is the average amount of solar radiation (unit: MJ / m) per day predicted during the period from 30 days before the heading stage to the heading stage (hereinafter referred to as the "target period"). 2 ) Note that the time point based on 30 days before the heading date basically means the time point 30 days before the heading date, but it is acceptable for the time point to be slightly earlier or later (for example, 29 days or 31 days before the heading date). This also applies to other cases where the expression "based on" is used.

[0016] The specific predicted solar radiation is derived in advance based on information on solar radiation published by the Japan Meteorological Agency, local governments, and other organizations and groups, as well as the results of observations by those managing the fields (a concept that includes organizations and groups), taking into consideration the trends in solar radiation to date and the status of various factors that affect solar radiation (including not only past conditions but also future conditions). The user enters the specific predicted solar radiation in input field N3. The specific predicted solar radiation is an index value that indicates the amount of sunlight during the target period, and corresponds to a "sunlight-related value."

[0017] The user inputs information into the input fields N1, N2, and N3, and then operates the confirm button B1 to confirm the input.

[0018] In response to operation of the Confirm button B1, the variety discrimination unit 11 acquires information (information indicating the variety of rice in the field) indicating the variety entered in the input field N1 (hereinafter referred to as the "input variety"), and determines whether the input variety is a predetermined specific variety (hereinafter simply referred to as the "specific variety"). Here, the memory unit 14 stores data recording a list of specific varieties, and the variety discrimination unit 11 uses this data to determine whether the input variety is a specific variety.

[0019] When the variety discrimination unit 11 determines that the input variety is a specific variety, the information providing unit 10 displays on the display device 2 information recommending that top dressing be applied to the input variety at a predetermined time (period or timing). In this manner, in this embodiment, when the variety of rice in the field is a specific variety, the information providing unit 10 provides information recommending that top dressing be applied to this specific variety at a predetermined time, regardless of the amount of solar radiation predicted for the target period. Here, the memory unit 14 stores data recording information indicating the recommended time for top dressing for each specific variety. The information providing unit 10 uses this data to provide the above information.

[0020] As an example, assume that the input variety is variety A, variety A is a specific variety, and the data stored in memory unit 14 includes information indicating the "heading stage" as information indicating the recommended time for top dressing for variety A. In this case, variety discrimination unit 11 displays, for example, the phrase "top dressing at the heading stage is recommended" on display device 2. The perspectives from which the specific variety was selected and the significance of such processing will be described later.

[0021] If the variety discrimination unit 11 determines that the input variety is not a specific variety, the leaf color intensity discrimination unit 12 acquires information (information indicating the leaf color of rice in the field) indicating the leaf color intensity (hereinafter referred to as the "input leaf color intensity") entered in the input field N2, and determines whether the leaf color intensity exceeds a predetermined threshold value (hereinafter referred to as the "leaf color threshold value," which corresponds to the "standard" in the claims).

[0022] When the leaf color intensity discrimination unit 12 determines that the input leaf color intensity exceeds the leaf color threshold, the information providing unit 10 displays information on the display device 2 recommending that no additional fertilization be performed. As an example, the information providing unit 10 displays the phrase "The leaf color is dark, so it is recommended that no additional fertilization be performed" on the display device 2. In other words, in this embodiment, when the leaf color intensity discrimination unit 12 determines that the leaf color is darker than the standard, the information providing unit 10 provides information recommending that no additional fertilization be performed, regardless of the amount of solar radiation expected for the target period. This is for the following reason.

[0023] That is, the inventors' research has experimentally confirmed that when the leaf color concentration exceeds a certain value, not applying top dressing has a positive effect on the condition of the harvested crop. One of the reasons for this is thought to be that when the leaf color concentration exceeds a certain value, nitrogen-based slow-release fertilizer applied when transplanting from the rice paddy to the field remains. Based on this, a leaf color threshold is pre-determined so that when the leaf color concentration exceeds the leaf color threshold, not applying top dressing will have a positive effect on the condition of the harvested crop. Furthermore, when the input leaf color concentration exceeds the leaf color threshold, not applying top dressing can have a positive effect on the condition of the harvested crop, so it is recommended not to apply top dressing.

[0024] By referring to the information displayed on the display device 2, the user can recognize that the leaf color is darker than the standard and therefore it is recommended not to apply additional fertilizer. Based on this recognition, the user can, for example, remeasure the remaining fertilizer status and the rice plant growth status, and consider whether to apply additional fertilizer and, if so, the timing of application. In other words, according to this embodiment, when the leaf color density is darker than the leaf color threshold, the user can be made aware of this fact and can be uniformly warned about applying additional fertilizer.

[0025] On the other hand, if the leaf color density discriminator 12 determines that the input leaf color density does not exceed the threshold, the sunlight-related value magnitude discriminator 13 executes the following process: That is, the sunlight-related value magnitude discriminator 13 acquires information indicating the specific predicted amount of solar radiation (hereinafter referred to as the "input predicted amount of solar radiation") entered in the input field N3, and determines whether the input predicted amount of solar radiation exceeds a predetermined threshold (hereinafter referred to as the "sun radiation threshold").

[0026] When the input predicted solar radiation amount exceeds the solar radiation amount threshold (i.e., when the sunlight-related value is high), the sunlight-related value amount discrimination unit 13 determines that the target period (as described above, the period from a point in time 30 days before the heading date to the heading date) is in a state of high sunshine (strictly speaking, it is expected to be in a state of high sunshine). A situation in which "the sunlight-related value amount discrimination unit 13 has determined that the target period is in a state of high sunshine" corresponds to a situation in which "the sunlight-related value amount discrimination unit has determined that the sunlight-related value is in a state of high sunshine." On the other hand, when the input predicted solar radiation amount does not exceed the solar radiation amount threshold (i.e., when the sunlight-related value is low), the sunlight-related value amount discrimination unit 13 determines that the target period is in a state of low sunshine (strictly speaking, it is expected to be in a state of low sunshine). A situation in which "the sunlight-related value amount discrimination unit 13 has determined that the target period is in a state of low sunshine" corresponds to a situation in which "the sunlight-related value amount discrimination unit has determined that the sunlight-related value is low." The perspectives by which the value of the sunlight amount threshold is set will be described later.

[0027] If the sunlight-related value amount discrimination unit 13 determines that the target period is one in which there is a lot of sunlight, the information providing unit 10 displays information on the display device 2 that recommends that the first top dressing be applied between "a time based on 35 days before the heading date" and "a time based on 15 days before the heading date." Hereinafter, the period from "a time based on 35 days before the heading date" to "a time based on 15 days before the heading date" will be referred to as the "period 35 to 15 days before."

[0028] On the other hand, if the sunlight-related value amount discrimination unit 13 determines that the target period is poorly irradiated, the information providing unit 10 displays information on the display device 2 that recommends that the first top dressing be applied between "a time point based on 15 days before the heading date" and "a time point based on 5 days after the heading date." Hereinafter, the period between "a time point based on 15 days before the heading date" and "a time point based on 5 days after the heading date" will be referred to as the "period from 15 days before to 5 days after."

[0029] As described above, in this embodiment, when the target period is predicted to be one with a lot of sunlight (when the sunlight-related value determination unit 13 determines that the sunlight-related value is high), the information providing unit 10 provides information recommending that the first top-dressing be performed in the "period 35 to 15 days before," and when the target period is predicted to be one with little sunlight (when the sunlight-related value determination unit 13 determines that the sunlight-related value is low), the information providing unit 10 provides information recommending that the first top-dressing be performed in the "period 15 days before to 5 days after." This is for the following reasons.

[0030] Figure 3 is a graph showing the trends in average solar radiation (changes in 2018 and 2019) in a certain region (hereinafter referred to as the "region of interest"). In Figure 3, the horizontal axis indicates the time period, and the vertical axis indicates the average daily solar radiation. In Figure 3, points P1-2018 and P1-2019 respectively indicate the average solar radiation for each day from the date of transplanting rice into the field to the "point based on 30 days before the heading stage" (hereinafter referred to as the "point 30 days before") (i.e., the average solar radiation per day for that period). For example, the "16.2" point at point P1-2018 indicates the average daily solar radiation for each day from the date of transplanting rice into the field to the "point based on 30 days before the heading stage" (hereinafter referred to as the "point 30 days before") (i.e., the average daily solar radiation for that period). <MJ / m 2 / day>" means that if the transplant date is 2018 / 5 / 17 and the point in time 30 days ago is 2018 / 7 / 3, the average daily solar radiation from 2018 / 5 / 17 to 2018 / 7 / 3 is 16.2 <MJ / m 2 / day>".

[0031] In addition, in Figure 3, points P2-2018 and P2-2019 respectively indicate the average amount of solar radiation for each day from the day after "30 days ago" to the heading stage (i.e., the average amount of solar radiation per day during that period).

[0032] Referring to Figure 3, it is clear that in the target area, the period in 2018 was significantly more sunny than average (the average amount of solar radiation was significantly higher than average), and the period in 2019 was significantly less sunny than average (the average amount of solar radiation was significantly lower than average).

[0033] Figure 4(A) is a graph showing the final harvest yield (units: kg / 10a) for a rice field of a certain variety (hereinafter referred to as the "variety of interest"; the variety of interest is not a specific variety) in a region of interest in 2018, when the first intensive top dressing was applied 30 days prior, 20 days prior (20 days prior is based on 20 days prior to heading; the same applies below), and at the heading stage. In Figure 4(A) and Figures 4(B), 5(A), and 5(B) described below, the 30-day period is referred to as the "first half," the 20-day period as the "middle," and the heading stage as the "second half." In Figure 4(A), bar K1 indicates that the harvest yield was 853 kg / 10a when the first top dressing was applied 30 days prior.

[0034] Figure 4(B) shows the final number of grains (unit: grains / m) when the first intensive top dressing was applied 30 days before, 20 days before, and at the heading stage in 2018. 2 In Figure 4(B), for example, bar K2 shows the number of rice grains when the first top dressing was applied 30 days ago, which is 52 × 10 3 (=52,000) pieces / m 2 This shows that it was.

[0035] Figure 5(A) is a graph showing the final yield when the first intensive top dressing was applied 30 days before, 20 days before, and at the heading stage in 2019. Figure 5(B) shows the final number of grains when the first intensive top dressing was applied 30 days before, 20 days before, and at the heading stage in 2019.

[0036] As shown in Figure 4(A), in 2018, when the target period was rich in sunlight, the results showed that when the first top dressing was applied 30 days prior, the yield was higher than when the first top dressing was applied 20 days prior or at the heading stage. Also, as shown in Figure 4(B), in 2018, when the target period was rich in sunlight, the results showed that when the first top dressing was applied 30 days prior, the number of grains was higher than when the first top dressing was applied 20 days prior or at the heading stage.

[0037] On the other hand, as shown in Figure 5(A), in 2019, when the target period was poor in sunlight, the results showed that the yield was higher when the first top dressing was applied at the heading stage compared to when the first top dressing was applied 30 days or 20 days prior. Also, as shown in Figure 5(B), in 2019, when the target period was poor in sunlight, the number of rice grains was lower when top dressing was applied 20 days prior, but the number of rice grains was almost the same when top dressing was applied 30 days prior to the heading stage.

[0038] The inventors investigated and studied the relationship between the combination of the amount of solar radiation (level) during the target period and the timing of top dressing, and the yield and number of unhulled grains of the harvested crop, as described above, and analyzed the effects of the amount of solar radiation (level) during the target period and the timing of top dressing on the yield and number of unhulled grains of the harvested crop. As a result, the inventors found that when the target period is one with high sunshine (relatively high average solar radiation), a high yield (large harvest) can be achieved (or at least tends to be achieved) by applying the first top dressing in the "period 35 to 15 days before." Furthermore, the inventors found that when the target period is one with low sunshine (relatively low average solar radiation), a certain level of yield can be ensured (or at least tends to be achieved) by applying the first top dressing in the "period 15 days before to 5 days after."

[0039] The above phenomenon is thought to occur for the following reasons. Paddy rice grains are formed between 30 days before heading and the heading period. Nitrogen in rice is involved in grain differentiation, while carbohydrates are involved in degeneration. The effect of nitrogen on increasing grain number is high around 30 days before heading and decreases as the time approaches heading. Based on the above, when the amount of solar radiation during the target period is high (i.e., there is a lot of sunlight), photosynthesis is active and carbohydrates are abundant, so it is thought that if nitrogen fertilizer is applied during the "35 to 15 day period," there will be a high number of differentiated grains and a low number of degenerated grains, resulting in a high yield through an increase in grain number.

[0040] On the other hand, when the amount of solar radiation during the target period is low (i.e., there is little sunlight), photosynthesis is insufficient and carbohydrates are low, so even if nitrogen fertilizer is supplied during the "35 to 15 days before period," although the number of differentiated grains increases, the number of degenerated grains also increases, so this is not reflected in an increase in the number of grains, and therefore the yield cannot be maintained at a constant level. On the other hand, by conducting the first top dressing after the "15 days before to 5 days after period," it is possible to avoid a situation where the supply of nitrogen fertilizer is not reflected in an increase in the number of grains, and it is expected that the yield can be maintained at a constant level.

[0041] The above-mentioned solar radiation threshold has been set in advance based on the results of tests and simulations, so that if the average daily solar radiation during the target period exceeds this solar radiation threshold, a high yield (large harvest) can be achieved by applying the first top dressing in the "period 35 to 15 days before," and if it is below this threshold, a certain level of yield can be secured by applying the first top dressing after the "period 15 days before to 5 days after."

[0042] As described above, when the sunlight-related value amount discrimination unit 13 determines that the target period is one in which there is a lot of sunlight, the information providing unit 10 displays information on the display device 2 that recommends applying the first top dressing during the "period 35 to 15 days before." As an example, the information providing unit 10 displays the following text on the display device 2: "We recommend applying top dressing during the period from about 35 days before the heading period to about 15 days before the heading period." By referring to the information displayed on the display device 2, the user can recognize that it is recommended to apply top dressing during the period from about 35 days before the heading period to about 15 days before the heading period, and can use this information as useful information when deciding the final timing of top dressing.

[0043] On the other hand, if the sunlight-related value amount discrimination unit 13 determines that the target period is one of low light, the information providing unit 10 displays information on the display device 2 that recommends applying the first top dressing during the "period from 15 days before to 5 days after." As an example, the information providing unit 10 displays the following text on the display device 2: "We recommend applying top dressing from about 15 days before to about 5 days after the heading period." By referring to the information displayed on the display device 2, the user can recognize that it is recommended to apply top dressing from about 15 days after the heading period to about 5 days after the heading period, and can use this information as useful information when deciding the final timing of top dressing.

[0044] As described above, when the variety discrimination unit 11 determines that the input variety is a specific variety, the information provision unit 10 displays on the display device 2 information recommending the application of top dressing at a predetermined time for the input variety. This is for the following reason. Specifically, the inventors have discovered that there are varieties that have the characteristic that, when the target period is full of sunlight, a high yield cannot be achieved (or at least there is a tendency for this to occur) even if the first top dressing is applied in the "period 35 to 15 days before," and that, when the target period is poor in sunlight, a high yield cannot be achieved (or at least there is a tendency for this to occur) even if the first top dressing is applied in the "period 15 days before to 5 days after." The specific variety is a variety that has such a characteristic.

[0045] For the above reasons, when the input variety is a specific variety, the information providing unit 10 provides information indicating the predetermined time for top-dressing for that specific variety, regardless of the amount of solar radiation expected for the target period. The specific variety is identified in advance through testing and simulation, and the optimal time for top-dressing for the specific variety is also identified in advance through testing and simulation. However, there are cases where the optimal time for top-dressing for a specific variety has not been identified, or where it is extremely difficult to identify for some reason. In such cases, for example, the information providing unit 10 may provide information that there is no recommended time for top-dressing according to the pre-set settings, or may provide information that recommends top-dressing using the usual method.

[0046] Next, an information providing method by the information providing device 1 will be described using a flowchart. Fig. 6 is a flowchart showing an example of the operation of the information providing device 1. As shown in Fig. 6, the user instructs the display of the input screen 16 (step SX1). In response to the instruction in step SX1, the information providing unit 10 displays the input screen 16 (Fig. 2) on the display device 2 (step SA1).

[0047] The user inputs appropriate information into the input fields N1, N2, and N3 of the input screen 16 and confirms the input by operating the Confirm button B1 (step SX2). The variety discrimination unit 11 determines whether the input variety entered into the input field N1 is a specific variety (step SA2).

[0048] If the variety discrimination unit 11 determines that the input variety is a specific variety (step SA2: YES), the information provision unit 10 displays information on the display device 2 recommending that additional fertilization be performed for the input variety at a predetermined period or timing (step SA3). Then, the processing of the flowchart ends.

[0049] If the variety discrimination unit 11 determines that the input variety is not a specific variety (step SA2: NO), the information providing unit 10 causes the leaf color intensity discrimination unit 12 to determine whether the input leaf color intensity entered in the input field N2 exceeds the leaf color threshold value (step SA4).

[0050] If the leaf color density discriminator 12 determines that the input leaf color density exceeds the leaf color threshold (step SA4: YES), information recommending not to apply additional fertilizer is displayed on the display device 2 (step SA5). The processing of the flowchart then ends. Note that the processing of step SA2 and the processing of step SA4 can be performed in any order.

[0051] If the leaf color intensity discrimination unit 12 determines that the input leaf color intensity does not exceed the threshold value (step SA4: NO), the sunlight-related value intensity discrimination unit 13 determines whether the input predicted solar radiation amount entered in the input field N3 exceeds the solar radiation amount threshold value (step SA6).

[0052] If the input predicted solar radiation amount exceeds the solar radiation amount threshold (step SA6: YES), the sunlight-related value amount discrimination unit 13 determines that the target period is one in which there is a lot of sunlight (step SA7). In response to the sunlight-related value amount discrimination unit 13 determining that the target period is one in which there is a lot of sunlight in step SA7, the information providing unit 10 displays on the display device 2 information that recommends that the first top dressing be applied between "a point in time based on 35 days before the heading date" and "a point in time based on 20 days before the heading date" (step SA8). Thereafter, the processing of the flowchart ends.

[0053] On the other hand, if the input predicted solar radiation amount does not exceed the solar radiation amount threshold (step SA6: NO), the sunlight-related value amount discrimination unit 13 determines that the target period is one with little sunshine (step SA9). In response to the sunlight-related value amount discrimination unit 13 determining that the target period is one with little sunshine in step SA9, the information providing unit 10 displays on the display device 2 information that recommends applying the first top dressing between "a time point based on 15 days before the heading date" and "a time point based on 5 days after the heading date" (step SA10). Thereafter, the processing of the flowchart ends.

[0054] <Modification of the first embodiment> Next, a modification of the first embodiment will be described.

[0055] In the first embodiment described above, the user inputs the specific predicted amount of solar radiation into the input field N3. In this regard, the following configuration may be adopted. That is, on the input screen 16, the user inputs information indicating whether the specific predicted amount of solar radiation will exceed the solar radiation threshold, rather than the specific predicted amount of solar radiation. The sunlight-related value amount determination unit 13 determines whether the specific predicted amount of solar radiation will exceed the solar radiation threshold (the amount of sunlight-related value) based on the input information. The above configuration may also be adopted. The above also applies to cases where the sunlight-related value is other than an "index value indicating the amount of solar radiation" (for example, an "index value indicating the temperature" described below).

[0056] In the first embodiment, the user inputs the specific predicted solar radiation amount in the input field N3. In this regard, the following configuration may be adopted. That is, instead of the user inputting the specific predicted solar radiation amount, the sunlight-related value magnitude discriminator 13 may acquire information indicating the specific predicted solar radiation amount (or information indicating whether the specific predicted solar radiation amount exceeds a solar radiation threshold) from an external device via a network. Alternatively, the sunlight-related value magnitude discriminator 13 may acquire information necessary for deriving the specific predicted solar radiation amount from an external device via a network, and derive the specific predicted solar radiation amount based on the acquired information. In this case, the external device may be, for example, a local server installed within a LAN, or, for example, a cloud server installed on a global network including the Internet. The above points also apply to cases where the sunlight-related value is something other than an "index value indicating the amount of solar radiation" (for example, an "index value indicating high or low temperature," as described below).

[0057] In the first embodiment, the specific predicted amount of solar radiation was for a target period from a point in time 30 days before the heading date to the heading date. In other words, the "predetermined period before the heading date" in the claims is a "target period from a point in time 30 days before the heading date to the heading date." In this regard, the "predetermined period before the heading date" is not limited to the target period. That is, the "predetermined period before the heading date" is a period before the heading date such that, when the sunlight-related value for that period is high (according to the example of the first embodiment, when the average daily solar radiation during that period exceeds a threshold value), it is expected that the condition of the harvested crop will be improved by applying the first top dressing between a time point based on 35 days before the heading date and a time point based on 15 days before the heading date, and when the sunlight-related value for that period is low (according to the example of the first embodiment, when the average daily solar radiation during that period does not exceed a threshold value), it is expected that the condition of the harvested crop will be improved by applying the first top dressing between a time point based on 15 days before the heading date and a time point based on 5 days after the heading date. Note that if the "predetermined period before the heading date" is in the past, it is possible to use actual values ​​(values ​​based on actual measurements) rather than predicted values ​​for the sunlight-related value. For example, if the sunlight-related value is an index value indicating the amount of solar radiation as in the first embodiment, the actual average amount of solar radiation per day for a predetermined period can be used. The above also applies to cases where the sunlight-related value is other than an "index value indicating the amount of solar radiation" (for example, an "index value indicating the temperature" described below).

[0058] In the first embodiment, the sunlight-related value was an index value indicating the amount of sunlight (i.e., the specific predicted amount of sunlight). In this regard, the sunlight-related value is not limited to an index value indicating the amount of sunlight. The sunlight-related value may be any value that serves as an index of the amount of sunlight for a predetermined period before the heading stage (the target period in the first embodiment).

[0059] For example, the sunlight-related value intensity determination unit 13 may be configured to use an "index value indicating the intensity of sunlight" as the sunlight-related value. In this case, the sunlight intensity may be, for example, the cumulative sunlight intensity over a predetermined period, or the average sunlight intensity per day over a predetermined period.

[0060] Furthermore, for example, the sunlight-related value intensity determination unit 13 may be configured to use an "index value indicating high or low temperature" as the sunlight-related value. In this case, the temperature is, for example, the average temperature per day over a predetermined period. Because there is a correlation between the amount of sunlight and the temperature, the index value indicating the temperature can be used as the sunlight-related value indicating the amount of sunlight without any problems, and it has been confirmed that this is not a problem.

[0061] Alternatively, the sunlight-related value amount discriminator 13 may be configured to use an "index value indicating the dry matter weight of rice plants at a predetermined timing before the heading date" (hereinafter referred to as the "dry matter weight-related index value") as the sunlight-related value. In this case, the predetermined timing may be a timing 30 days or earlier (for example, 30 days or 40 days before the heading date). However, the predetermined timing is not limited to these examples and may be any timing at which the effect of sunlight during the period from the transplanting date to the predetermined timing is reflected in the dry matter weight and the amount of sunlight during that period can be determined based on the dry matter weight. Here, if there is a lot of sunlight (high solar radiation or long solar radiation duration) between the transplanting date and the predetermined timing, the amount of carbohydrates stored in the rice plants through photosynthesis increases, and the dry matter weight of the rice plants increases accordingly. In other words, there is a correlation between the amount of sunlight and the dry matter weight, and it has been confirmed that the dry matter weight-related index value can be used as the sunlight-related value without any problems. In this example, the period from the transplanting date to the predetermined timing corresponds to the predetermined period, and the dry matter weight-related index value corresponds to an index value indicating the amount of sunlight for the period from the transplanting date to the predetermined timing. Of course, the sunlight-related value amount determining unit 13 may use an index value indicating a growth-related trait correlated with dry matter weight as the sunlight-related value instead of the dry matter weight-related index value.

[0062] Alternatively, the sunlight-related value amount discriminator 13 may be configured to use an "index value indicating the amount of dry matter gain of rice plants during a predetermined period" (hereinafter referred to as "dry matter gain-related index value") as the sunlight-related value. In other words, the dry matter gain-related index value is an index value indicating how much the dry matter weight of rice plants has changed (increased) from the beginning to the end of the predetermined period. In this case, the beginning of the predetermined period may be the "transplanting period," and the end may be a predetermined timing 30 days or earlier (for example, 30 days or 40 days before the heading period). However, the combination of the beginning and end is not limited to the above example, and may be any combination that sufficiently reflects the amount of sunlight in the dry matter gain and allows the amount of sunlight for the predetermined period to be discriminated based on the amount of dry matter gain. It goes without saying that the sunlight-related value discriminator 13 may use an index value indicating a change correlated with the amount of dry matter gain as the sunlight-related value, instead of the dry matter gain-related index value.

[0063] The sunlight-related value amount discriminator 13 may also be configured to use the "index value indicating the early or late transplanting date" as the sunlight-related value. In this case, for example, the sunlight-related value discriminator 13 determines that the sunlight-related value is high if the transplanting date is earlier than a predetermined reference date, and determines that the sunlight-related value is low if the transplanting date is later. The earlier the transplanting date, the longer the period during which rice plants in the field receive sunlight. In other words, there is a correlation between the amount of sunlight and the early or late transplanting date, and it has been confirmed that the "index value indicating the early or late transplanting date" can be used as the sunlight-related value without any problems.

[0064] In the above embodiment, when the sunlight-related value intensity discriminator 13 determines that the target period is low in sunlight (when the sunlight-related value is determined to be low), the information provider 10 provides (specifically, displays on the display device 2) information recommending that the first top dressing be applied in the "period from 15 days before to 5 days after" (hereinafter referred to as "low-sunlight recommendation information"). In this regard, instead of the low-sunlight recommendation information, the information provider 10 may provide either information indicating that "not applying top dressing may be effective" or information indicating that "following the customary practices (local cultivation calendar) may be effective" (obviously, both may be provided). As described above, applying the first top dressing in the "period from 15 days before to 5 days after" can ensure a certain level of yield (at least there is a tendency for this to be the case). However, when the target period is low in sunlight, there are cases where not applying top dressing or following the customary practices can ensure the same or higher yield. Providing the above information makes it possible to provide useful information to the user. In addition, the information providing unit 10 may be configured to provide, together with the recommended information for times of low light, either information indicating that "not applying top dressing may be effective" or information indicating that "following customary practices (local cultivation calendars) may be effective" (naturally, it may provide both).

[0065] Second Embodiment Next, a second embodiment will be described. In the following description of the second embodiment, the same elements as those in the first embodiment will be assigned the same reference numerals, and their description will be omitted. FIG. 7 is a block diagram showing an example of the functional configuration of an information providing device 1A according to this embodiment. As shown in FIG. 7, the information providing device 1A according to this embodiment includes an information providing unit 10A instead of the information providing unit 10, and a sunlight-related value magnitude determining unit 13A instead of the sunlight-related value magnitude determining unit 13. The operation of the information providing device 1A will be described below using a flowchart.

[0066] Fig. 8 is a flowchart showing an information providing method by the information providing device 1 A. In the flowchart of Fig. 8, steps having the same processing content as the steps of Fig. 6 are given the same reference numerals.

[0067] As shown in FIG. 8, when a user instructs the display of the input screen 16A (step SX1), the information provider 10A displays the input screen 16A (FIG. 9) on the display device 2 (step SB1). FIG. 9 is a diagram showing an example of the input screen 16A. As is clear from a comparison with FIG. 2, the input screen 16A has an input field N4 in addition to input fields N1 to N3. The input field N4 is a field for inputting the date of the transplanting period (the date on which rice was transplanted in the current season). In this embodiment, the user inputs information indicating the date of the transplanting period into the input field N4 in addition to the input fields N1 to N3. Hereinafter, the date of the transplanting period indicated by the information input into the input field N4 will be referred to as the "input transplanting period date."

[0068] In step SA6 of FIG. 8, if the input predicted solar radiation amount does not exceed the solar radiation amount threshold (step SA6: NO), the sunlight-related value amount determination unit 13A determines that the target period is one of low sunshine (step SA9), and in response, the information providing unit 10A displays on the display device 2 information recommending that the first top dressing be applied during the period from 15 days before to 5 days after (step SA10). The above processing is the same as in the first embodiment. The processing in step SA6 corresponds to "processing for determining the amount of the first sunlight-related value, which is an index of the amount of sunlight in the target period."

[0069] On the other hand, if the input predicted solar radiation exceeds the solar radiation threshold (step SA6: YES), the sunlight-related value amount discriminator 13A determines whether the input transplantation date is earlier than a predetermined transplantation reference date (step SB2). The perspective on which the transplantation reference date is set will be described later. The processing of step SB2 corresponds to "processing to discriminate the amount of second sunlight-related value, which is an indicator of the amount of sunlight for the transplantation-related period" (the reason for this will become clear later).

[0070] If the sunlight-related value amount discriminator 13A determines in step SB2 that the input transplanting date is not earlier than the transplanting reference date (step SB1: NO), the information provider 10A displays on the display device 2 information that recommends applying the first top dressing during the "period 35 to 15 days before" (step SA8). If the sunlight-related value discriminator 13A determines in step SB2 that the input transplanting date is earlier than the transplanting reference date (step SB2: YES), the information provider 10A displays on the display device 2 information that recommends applying the first top dressing at an early stage during the "period 35 to 15 days before" (i.e., provides the information) (step SB3).

[0071] Here, if the input transplanting date is earlier than the transplanting reference date, it means that the period from transplanting to the "30 days prior" (the transplanting-related period) is longer, and the period during which the rice in the field received sunlight is longer (more sunlight) compared to when the input transplanting date is later than the transplanting reference date. Based on the above, the input transplanting date can be thought of as a second sunlight-related value that serves as an indicator of the amount of sunlight for the period from transplanting to the 30 days prior (the transplanting-related period); if the input transplanting date is earlier than the transplanting reference date, the second sunlight-related value is high, and if the input transplanting date is not earlier than the transplanting reference date, the second sunlight-related value is low.

[0072] As described above, in this embodiment, if the specific predicted solar radiation exceeds the solar radiation threshold (the first sunlight-related value is high) and the input transplanting date is earlier than the transplanting reference date (the second sunlight-related value is high), the information provider 10A provides information recommending that the first top dressing be applied early in the "period 35 to 15 days before." This is for the following reason.

[0073] Figure 10 is a graph showing the final yield for each of the following cases in a certain region in a year in which the target period was sunny (i.e., the average solar radiation during the target period exceeded the solar radiation threshold). Case C1: The transplanting date was earlier than the reference date for transplanting, and the first intensive top dressing was applied 30 days prior. Case C2: The transplanting date was earlier than the reference date for transplanting, and the first intensive top dressing was applied 20 days prior. Case C3: The transplanting date was later than the reference date for transplanting, and the first intensive top dressing was applied 30 days prior. Case C4: The transplanting date was later than the reference date for transplanting, and the first intensive top dressing was applied 20 days prior. 10, the reference transplant date for cases C1 to C4 is "June 1st." The transplant date for cases C1 and C2 is "May 17th," and the transplant date for cases C3 and C4 is "June 14th."

[0074] In FIG. 10, graph G10-1 corresponds to case C1 and shows that the yield was 1009 kg / 10a. Graph G10-2 corresponds to case C2 and shows that the yield was 956 kg / 10a. Graph G10-3 corresponds to case C3 and shows that the yield was 930 kg / 10a. Graph G10-4 corresponds to case C4 and shows that the yield was 907 kg / 10a.

[0075] 11 is a graph showing the final number of unhulled grains in each of the above cases. In FIG. 11, graph G11-1 corresponds to case C1, and the number of unhulled grains is 51×10 3 pieces / m 2 Graph G11-2 corresponds to case C2, and shows that the number of rice grains was 47 × 10 3 pieces / m 2 Graph G11-3 corresponds to case C3, and shows that the number of rice grains was 50 × 10 3 pieces / m 2 Graph G11-4 corresponds to case C4, and shows that the number of rice grains was 46 × 10 3 pieces / m 2 This shows that it was.

[0076] As shown in Figures 10 and 11, in this year, both yield and number of unhulled grains were significantly higher when the first intensive top dressing was applied 30 days prior to the transplanting date compared to when the transplanting date was earlier or later than the reference transplanting date. The inventors investigated and studied the relationship between the early and late transplanting date and the "yield and number of unhulled grains" when the target period is full sun, as described above. As a result, the inventors found that when the target period is full sun (relatively high average solar radiation), high yields (large harvests) can be achieved (or at least tend to be) by applying the first top dressing early in the "35-15 days prior period," particularly before the 30th day. The following is presumed to be the reason for this. Specifically, one presumed reason is that when the solar radiation during the target period is high and the transplanting date is earlier than the reference transplanting date, carbohydrates accumulated in the rice plant contribute to improved ripening (even if the number of unhulled grains increases, the unhulled grains are fuller).

[0077] If the transplanting period is earlier than this reference date, the first intensive top dressing application should be carried out early in the "35-15 day period" to achieve an effective high yield (large harvest). The reference date for transplanting is set in advance based on the results of tests and simulations.

[0078] <Modification of the second embodiment> Next, a modification of the second embodiment will be described.

[0079] In the second embodiment, the sunlight-related value amount discrimination unit 13A used the specific predicted amount of solar radiation as the "first sunlight-related value" in the claims. However, the first sunlight-related value is not limited to the specific predicted amount of solar radiation, and may be any index value that indicates the amount of sunlight during the target period (the period from 30 days before to the heading stage). For example, the "index value indicating the amount of sunshine hours during the target period" or the "index value indicating the temperature level during the target period" described in the modified example of the first embodiment can be used as the first sunlight-related value.

[0080] In the above embodiment, the sunlight-related value intensity discriminator 13A used the date of the transplanting period as the "second sunlight-related value" in the claims. However, the second sunlight-related value is not limited to the date of the transplanting period, and may be any index value that indicates the amount of sunlight during the transplanting-related period (the period from the transplanting period to the "predetermined timing 30 days prior"). For example, the sunlight-related value intensity discriminator 13A can use an "index value indicating the amount of solar radiation during the transplanting-related period," an "index value indicating the amount of sunshine during the transplanting-related period," or an "index value indicating the temperature during the transplanting-related period" as the second sunlight-related value. Furthermore, for example, the sunlight-related value intensity discriminator 13A can use an index value indicating the dry weight of rice or a growth-related trait correlated with the dry weight at a predetermined timing 30 days prior to the transplanting period as the second sunlight-related value. For example, the sunlight-related value amount discrimination unit 13A can use an index value indicating the amount of dry matter increase in rice or a change correlated with the amount of dry matter increase at a specified time before 30 days from the transplanting date as the second sunlight-related value.

[0081] Furthermore, when the sunlight-related value amount discrimination unit 13 determines that the target period is one of low light, the information providing unit 10A may be configured to provide either information indicating that "it may be effective not to apply top dressing" or information indicating that "it may be effective to follow customary practices (local cultivation calendars)" (naturally, both are also acceptable), in addition to or instead of the recommended information for low light.

[0082] Although the embodiments of the present invention have been described above, the above-described embodiments are merely examples of specific embodiments for carrying out the present invention, and the technical scope of the present invention should not be construed as being limited thereby. In other words, the present invention can be carried out in various forms without departing from the gist or main characteristics thereof.

[0083] For example, in the first embodiment, the information providing device 1 was equipped with the variety discrimination unit 11 and the leaf color discrimination unit 12, but it may be configured to not include one or both of these. This also applies to the second embodiment. In the first embodiment, if the variety discrimination unit 11 is not included, the input field N1 is not provided on the input screen 16. Furthermore, with reference to the flowchart of FIG. 6, the processes of steps SA2 and SA3 are not performed, and after step SA1, the processing procedure proceeds to step SA4. In addition, in the configuration without the leaf color discrimination unit 12, the input field N2 is not provided on the input screen 16. Furthermore, with reference to the flowchart of FIG. 6, the processes of steps SA4 and SA5 are not performed, and if step SA2: NO, the processing procedure proceeds to step SA6.

[0084] Furthermore, in the case where the first embodiment is configured without the variety discrimination unit 11 and the leaf color density discrimination unit 12, the input fields N1 and N2 are not provided on the input screen 16. Furthermore, referring to the flowchart in Figure 6, the processing of steps SA2, SA3, SA4, and SA5 is not performed, and after step SA1, the processing procedure proceeds to step SA6. Note that even in the above configuration, the information provided by the information providing device 1 does not force the application of top dressing at the time indicated by the information, but is merely useful information that the user can refer to when making a final decision on the time to apply top dressing, and does not cause any disadvantage to the user.

[0085] Furthermore, in the first embodiment, the storage unit 14 may be configured to be an external storage device different from the information providing device 1. Furthermore, the information providing device 1 may be configured as a server on the Internet, and when a client requests information regarding the timing of top dressing via the Internet, the information providing device 1 may acquire the necessary information using the above-described method and provide the information regarding the timing of top dressing. Furthermore, the information providing device 1 does not need to be a single computer, but may be configured with multiple computers. For example, a configuration may be possible in which a terminal connected via the Internet and a cloud server work together to function as the information providing device 1, and the terminal works with the cloud server as appropriate to execute various processes. The above points are also true for the second embodiment.

[0086] In the first embodiment, the information providing unit 10 provides information by displaying the information on the display device 2, but the method by which the information providing unit 10 provides information is not limited to the method exemplified in the above embodiment. As an example, the information providing unit 10 may provide information by printing on a paper medium, by e-mail, by displaying on a browser by outputting an HTML file, by audio output, etc. The above points also apply to the second embodiment. [Explanation of symbols]

[0087] 1, 1A Information provision device 10, 10A Information provision department 11 Variety Discrimination Department 12 Leaf color dark / light discrimination section 13, 13A Sunlight related value amount discrimination section

Claims

1. An information providing device that provides information on top dressing for rice fields, a sunlight-related value amount discrimination unit that discriminates the amount of a first sunlight-related value that is an index of the amount of sunlight for a target period from a reference point 30 days before the heading period to the heading period, and discriminates the amount of a second sunlight-related value that is an index of the amount of sunlight for a transplanting period from the transplanting period to a predetermined timing at or before 30 days before the heading period; When the sunlight-related value magnitude determining unit determines that the first sunlight-related value is large and the sunlight-related value magnitude determining unit determines that the second sunlight-related value is large, information is provided recommending that a first top dressing be applied at an early stage within a period from a reference point 35 days before the heading date to a reference point 15 days before the heading date, When the sunlight-related value magnitude determining unit determines that the first sunlight-related value is large and the sunlight-related value magnitude determining unit determines that the second sunlight-related value is small, providing information recommending that a first top dressing be applied between a time point based on 35 days before the heading date and a time point based on 15 days before the heading date, and an information providing unit that, when the sunlight-related value amount determining unit determines that the first sunlight-related value is small, provides information that recommends that a first top dressing be performed between a time point set as 15 days before the heading date and a time point set as 5 days after the heading date. An information providing device characterized by:

2. The sunlight-related value amount determining unit uses an index value indicating the amount of sunlight in the target period or an index value indicating the amount of sunlight in the target period as the first sunlight-related value.

2. The information providing device according to claim 1.

3. The sunlight-related value magnitude determining unit uses an index value indicating whether the temperature is high or low during the target period as the first sunlight-related value.

2. The information providing device according to claim 1.

4. The sunlight-related value amount determining unit uses an index value indicating the amount of sunlight in the transplantation period-related period or an index value indicating the amount of sunlight in the transplantation period-related period as the second sunlight-related value.

2. The information providing device according to claim 1.

5. The sunlight-related value amount determining unit uses an index value indicating whether the temperature is high or low during the transplantation period as the second sunlight-related value.

2. The information providing device according to claim 1.

6. The sunlight-related value amount determining unit uses, as the second sunlight-related value, an index value indicating the dry matter weight of rice at a predetermined timing 30 days or earlier before the heading date or a growth-related trait correlated with the dry matter weight, or an index value indicating the dry matter increase amount of rice from the heading date to a predetermined timing 30 days or earlier before the heading date or a change amount correlated with the dry matter increase amount.

2. The information providing device according to claim 1.

7. The sunlight-related value amount determining unit uses an index value indicating whether the transplantation period is early or late as the second sunlight-related value.

2. The information providing device according to claim 1.

8. The method further includes a leaf color density discrimination unit that acquires information indicating the leaf color of rice plants in the field and determines whether the leaf color is darker than a reference value, The information providing unit provides information that recommends not applying additional fertilizer when the leaf color density determining unit determines that the leaf color is darker than a reference value.

2. The information providing device according to claim 1.

9. The system further includes a variety discrimination unit that acquires information indicating the variety of rice in the field and determines whether the variety is a predetermined specific variety, When the variety discrimination unit determines that the variety is the specific variety, the information provision unit provides information recommending that additional fertilization be performed on the specific variety at a predetermined time.

2. The information providing device according to claim 1.

10. An information providing method using an information providing device that provides information about top dressing for a rice field, comprising: a sunlight-related value amount discrimination unit discriminating the amount of a first sunlight-related value that is an index of the amount of sunlight for a target period from a reference point 30 days before the heading period to the heading period, and discriminating the amount of a second sunlight-related value that is an index of the amount of sunlight for a transplanting period from the transplanting period to a predetermined timing 30 days before the heading period; The information department When the sunlight-related value magnitude determining unit determines that the first sunlight-related value is large and the sunlight-related value magnitude determining unit determines that the second sunlight-related value is large, information is provided recommending that a first top dressing be applied at an early stage within a period from a reference point 35 days before the heading date to a reference point 15 days before the heading date, When the sunlight-related value magnitude determining unit determines that the first sunlight-related value is large and the sunlight-related value magnitude determining unit determines that the second sunlight-related value is small, providing information recommending that a first top dressing be applied between a time point based on 35 days before the heading date and a time point based on 15 days before the heading date, and providing information that recommends applying a first top dressing between a time point set as 15 days before the heading date and a time point set as 5 days after the heading date when the first sunlight-related value is determined to be low by the sunlight-related value amount determining unit.

1. An information providing method comprising:

Images