JP2019041582A - Plant production method - Google Patents

Abstract

To provide a plant production method capable of controlling a weight of plants to be harvested to a desired range (in specification) even when there is variation of growth (growth speed) of plants in a plant factory or the like.SOLUTION: The plant production method comprises at least: a greening step for disseminating seeds of a plant group formed of at least one plant, causing to sprout and grow for acquiring young seedlings; a seedling raising step for transplanting the young seedlings to a seedling raising chamber for causing the young seedlings to grow, for acquiring fix planted seedlings; and a main cultivation step for transplanting the fix planted seedlings and causing to grow, then harvesting the fix planted seedlings. For each plant forming the plant group, pieces of data of a weight at plural time points in the seedling raising step are collected, and based on the collected weight data, a relational expression between a total cultivation period which is a total period of the greening period, the seedling raising period and main cultivation period, and the weight of the plant group, is generated, then, based on the relational expression, for the plant group, the total cultivation period is adjusted so that, a ratio of the plants having a weight in a prescribed range out of the harvested plants, is optimized.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a method of producing a plant.

  Plant plants (for example, artificial light plant plants and solar light plant plants) are positioned as one pillar to realize agricultural industrialization and business management, and have high expectations as an export industry, so plant plant technology Development attracts industry attention.

  However, in the production of plants in plant factories, the growth of plants is uneven (due to growth variation), and there is a problem that the production is not stable (the profit is not stable due to growth variation). For example, there are two types of vegetable sales: weight sale (non-standard) and bag sale (separate items in the standard). When plant growth variation is large, non-standard ones increase and the ratio of low-sales weight sellers increases, which lowers the profitability of the plant factory.

  Several systems or software have already been proposed to predict the yield, harvest time, etc. (see, for example, Patent Document 1 (WO 2013/088539)). However, in these cases, the first approximation / quasi-static model based on population average or time average is used, and individual dynamic characteristics are not sufficiently analyzed (weight measurement of individual plants, etc. is performed). Production instability (the phenomenon in which the growth suddenly becomes poor) is not sufficiently analyzed. Therefore, it is considered that these conventional systems can not sufficiently avoid the production instability and the like in the plant factory.

International Publication No. 2013/0888539

  An object of the present invention is to provide a method of producing a plant capable of controlling the weight of a plant to be harvested within a desired range (within specification) even when plant growth (growth rate) varies in a plant factory or the like. It is to provide.

[1] A greening step, wherein a seedling is obtained by sowing a seed of a plant group consisting of at least one plant, and germinating and growing the seedling;
A seedling raising process, wherein fixed seedlings are obtained by transplanting the seedlings in a nursery room and growing them;
And a main cultivation step of harvesting the planted seedlings after transplanting them into a cultivation room and growing them, and producing the plant,
Collecting data of weights at multiple time points of the raising step for individual plants constituting the group of plants;
From the collected weight data, a total of a greening period which is a period to carry out the greening step, a breeding period which is a period to carry out the seedling raising step, and a main cultivation period which is a period to carry out the main cultivation step Create a relational expression between the total cultivation period, which is the period, and the weight of the plant group,
The plant production method, wherein the total cultivation period is adjusted based on the relational expression such that a proportion of plants having a weight within a predetermined range among plants to be harvested is optimized for the plant group.

[2] The relational expression is an expression obtained by fitting the following equation (1) to the data of the weight and determining the coefficients K and W ₁ related to growth in the following equation (1), [1 ] The production method of the plant as described in.

[In the formula (1),
t is the total cultivation period (day),
t ₁ is the greening period (day),
W (t) is an average value of the weight of the plant group when the total cultivation period t (day) has passed,
W _max is the assumed maximum weight (g) of the plant,
W ₁ is the weight (g) of the seedling of the plant,
K is the growth rate. ]

  [3] The method of producing a plant according to [1] or [2], wherein the data of weight is obtained by estimation based on a measured value of leaf area.

[4] A price per weight of a plant having a threshold weight or more, which is a minimum value of the weight of a plant sold in a bag among the plant group, and a price per weight of a plant less than the threshold weight in the plant group. To maximize the profit margin gained by the production and sale of said plant groups based on the ratio of
The method for producing a plant according to any one of [1] to [3], wherein the proportion of plants having a weight within a predetermined range among the plants to be harvested is optimized for the group of plants.

  [5] The method for producing a plant according to any one of [1] to [4], wherein the total cultivation period is adjusted by adjusting the main cultivation period.

[6] The total cultivation period is adjusted by adjusting the main cultivation period,
The method for producing a plant according to [4], wherein the main cultivation period is adjusted based on the following formula (2) so as to maximize the profit margin.

[In formula (2),
Y (t, w ^* , λ) is the profit ratio per plant (/ strain),
w ^* is the threshold weight (g),
r ^* is the percentage of stocks with a weight of w ^* or more (bag-selling stocks) (/ stock)
λ is the ratio of the price per weight of the heavy sale item to the price per weight of the bag sale item,
<W> is the average weight (g) of stocks less than w ^* (weight-selling stocks),
P is the purchase rate, which is the rate at which consumers buy bag-selling products,
α is fixed cost (/ stock),
β is the utility cost (/ (day, stock)) in the greening step and the seedling step for each strain per day per day,
γ is the cost of utilities (/ (day, stock)) in the main cultivation process per share per day,
t ₁ is the greening period (day),
t _2, said a nursery period (day). ]

  [7] The method for producing a plant according to any one of [1] to [4], wherein the total cultivation period is adjusted by adjusting the nursery period.

[8] The total cultivation period is adjusted by adjusting the nursery period,
The method for producing a plant according to [4], wherein the main cultivation period is adjusted based on the following formula (3) so that the profit margin is maximized.

[In formula (3),
Y (t, w ^* , λ) is the profit ratio per plant (/ strain),
w ^* is the threshold weight (g),
r ^* is the percentage of stocks with a weight of w ^* or more (bag-selling stocks) (/ stock)
λ is the ratio of the price per weight of the heavy sale item to the price per weight of the bag sale item,
<W> is the average weight (g) of stocks less than w ^* (weight-selling stocks),
P is the purchase rate, which is the rate at which consumers buy bag-selling products,
α is fixed cost (/ stock),
β is the utility cost (/ (day, stock)) in the greening step and the seedling step for each strain per day per day,
γ is the cost of utilities (/ (day, stock)) in the main cultivation process per share per day,
t _3, the is present cultivation period (day). ]

  According to the plant production method of the present invention, even when plant growth (growth rate) is uneven in a plant factory etc., the weight of the plant to be harvested can be controlled within a desired range (within specification). .

It is a flowchart which shows each process of the production method of the plant of this invention. It is a schematic diagram which shows an example of the system used for the production method of the plant of this invention. It is a schematic diagram for demonstrating an example of the system used for the production method of the plant of this invention. It is a graph which shows the relationship between the threshold weight w ^{* of a} plant, and the purchase rate P. It is a graph for demonstrating adjustment of the main cultivation period in Embodiment 1. FIG. (A) is a graph mainly for demonstrating a seedling raising period, (b) is a graph for mainly demonstrating a main cultivation period. It is a graph for demonstrating adjustment of the nursery seeding period in Embodiment 2. FIG. (A) is a graph mainly for demonstrating a seedling raising period, (b) is a graph for mainly demonstrating a main cultivation period. (A) is a graph showing the correlation between leaf area and weight. (B) is a photograph for demonstrating the measurement of the leaf area by image processing. It is a graph for demonstrating the measurement of the leaf area in a raising seedling process. (A) is a graph up to 240 hours of nursery period, (b) is a graph up to 336 hours of nursery period. 10 is a graph showing the relationship between the threshold weight w ^* and the total cultivation period t and the profit ratio Y in Embodiment 1. It is a schematic diagram for demonstrating the production method of the conventional plant. It is a schematic diagram for demonstrating the production method of the plant of Embodiment 1. FIG. 15 is a graph showing the relationship between the threshold weight w ^* and the total cultivation period t and the profit rate Y in Embodiment 2. It is a schematic diagram for demonstrating the production method of the conventional plant. It is a schematic diagram for demonstrating the production method of the plant of Embodiment 2. FIG.

(Plant production method)
Referring to FIG. 1, the method for producing a plant of the present invention is
Planting a seed of a group of plants consisting of at least one plant, sprouting and growing to obtain seedlings;
The seedling raising process, obtaining fixed planted seedlings by transplanting the seedlings into the nursery room and growing them.
And a main cultivation step of harvesting the planted seedlings after transplanting and growing them in a cultivation room.

  From the viewpoint of enhancing the production efficiency of plants, it is preferable that seedlings selected by a seedling sorting robot or the like be transplanted for the young seedlings and the fixed planted seedlings.

  The plant to be cultivated (produced) of the present invention is not particularly limited, and examples thereof include edible plants, medicinal plants, ornamental plants and the like. The plants are preferably edible plants. As edible plants, for example, leaf vegetables such as lettuce, Komatsuna, spinach, sanchu, minced vegetables, chrysanthemum, herbs (rucola, basil, perilla, perianthus, dokudami, etc.), real products such as eggplant, cucumber, tomato, sweet pepper Fruits such as vegetables, strawberries, tangerines, mangoes, grapes and pears; grains such as rice, wheat, barley, rye, oats, corn, sorghum, millet, barnyard millet and the like. Leafy vegetables are preferred in that it is easy to estimate the weight (raw weight) from the leaf area of the seedlings. Examples of ornamental plants include, for example, flower plants such as roses, carnations, orchids, gerberas, boobs and the like; potted plants such as potos, selom and asian tam. The plant may be a genetically modified plant.

  The present inventors have found that variation in the growth of seedlings in the step of raising seedlings is one of the factors that make plant plant production unstable. In the seedling raising process, it is thought that the variation in the growth of the seedling tends to occur due to individual differences in species and slight differences in cultivation conditions in the greening step and the seedling raising step. In addition, in the seedling raising process, there is a tendency that the variation in growth tends to be large, accompanied by a qualitative change in growth such as the formation of young leaves to true leaves.

  For this reason, in the method of producing a plant of the present invention, first, for individual plants constituting a plant group, data (for example, data of weight and weight distribution) of weight (raw weight) at plural time points of the raising step collect. Then, from the collected weight data, the growth amount (weight) of plants (plant group) in the main cultivation step is predicted.

  The plant group is not particularly limited as long as it is a group consisting of at least one plant (preferably a plurality of plants), and for example, it comprises at least one plant sown on a predetermined area in a plant factory A group etc. are mentioned.

  Specifically, a relational expression of the total cultivation period and the weight of the plant group can be created, and the predicted value of the weight of the plant harvested after the elapse of a certain total cultivation period can be calculated from the relational expression. Here, from the collected weight data, the total cultivation period is a greening period which is a period for carrying out the greening step, a nursery period for which the seedling raising step is carried out, and a period for which the main cultivation step is carried out. This is the total period of the main cultivation period.

The relational expression is not particularly limited as long as it is possible to calculate the predicted value of the weight of the plant, but preferably, the following formula (1) is fitted to the data of weight and the growth in the following formula (1) is related. It is an equation obtained by determining the coefficients K and W ₁ .

Each symbol in the said Formula (1) is as follows.
t: Total cultivation period (day) [total period from sowing to (harvest)]
t ₁ : Greening period (day) [period from sowing to transplanting to nursery room]
W (t): Plant weight (g) [weight of plant when total cultivation period t (day) has passed]
W _max : Maximum weight (g) [maximum value of weight usually assumed per plant species]
W ₁ : Seedling weight (g) [Weight of plant (seedling) at the time of transplantation to the nursery room (at time t ₁ )]
K: Growth rate In addition, when a plant group consists of several plants, W (t) is an average value about a certain plant group.

  Weight data can be obtained, for example, by estimation based on measurement of leaf area of plant when leaf area of individual plant is correlated with plant weight (raw weight of above-ground part) Can.

  However, since the leaf area is obtained by analysis of a two-dimensional image, when the plant grows and the number of leaves increases, overlapping of leaves occurs, and it becomes impossible to obtain an accurate leaf area from the two-dimensional image. For this reason, it is necessary to approximate growth of a plant, for example, with a logistics curve (the above-mentioned formula (1)), and to obtain a growth curve (curve showing an expected value of the weight of a plant).

In order to determine plant growth, both W ₁ and K of the growth parameters of equation (1) are required. In order to determine both W ₁ and K, time series data as shown in FIG. 8A is required.

Equation (1) is fitted to the time-series data of leaf area Li (mm ² ) in FIG. 8 (a) to obtain the coefficients K and W _1, and an approximate curve as shown by a dotted line in FIG. You can get it. In addition, _Wmax in Formula (1) was made into the constant (180 g) here based on the experimental result so far.

  The approximate curve can be obtained using non-linear GRG (non-linear programming). For non-linear GRG, for example, URL [http://www.orsj.or.jp/archive2/or57-04/or57_4_175.pdf#search=%27GRG%E9%9D%9E%E7%B7%9A%E5% See, for example, p. 181 of BD% A2% 27].

  In addition, it is not necessary to measure the weight (leaf area) of a seedling about all the strains of a plant group, it measures about some strains of a plant group, and estimates the measured value of the whole plant group from those measured values. You may In addition, since the growth variation (dispersion) in a plant factory is very large, for example, it is preferable to measure the weight (leaf area) of at least about 10% of the whole production. For example, in the case of a plant plant of 5000 stocks of Nissan, it is preferable to carry out the measurement for at least 500 stocks.

  And, in the method of producing a plant of the present invention, further, based on the relational expression, in the plant group, the ratio of plants having a weight within a predetermined range among the plants to be harvested is optimized. Cultivation period is adjusted.

“The proportion of plants having a weight within a predetermined range among the plants to be harvested is optimized” means, for example, the price per weight of plants having a predetermined threshold weight w ^* or more of plant groups, and the plant group The profit ratio obtained by the production and sale of the plant group is maximized on the basis of the ratio of the price per weight of the plant below the threshold weight. That is, by minimizing the cost required for the production of plants in as short a total cultivation period as possible, the proportion of plants having a weight above the predetermined threshold weight w ^* among the harvested plant groups is made as high as possible. , The profit margin can be maximized.

For example, in consideration of different sales forms (bag sale and weight sale) according to plant growth amount (weight), construct a diagram for obtaining profitability (profit ratio) for each sale form, and all sales Formulas (for example, the above formulas (2) and (3)) for finding the total rate of return of the form are prepared. In the above equations (2) and (3), the threshold weight w ^* (shipment threshold) which is the minimum value of the weight of the plant sold as a bag is one parameter of the formula. Then, using such a formula, a total cultivation period t (optimum cultivation period) or the like in which the total return rate of all the sales forms is maximized is determined.

  By adjusting the total cultivation period of the plant group according to the optimal cultivation period thus determined, the profit ratio of the plant group can be maximized. In addition, for example, as in the first embodiment described later, the total cultivation period may be adjusted by adjusting the main cultivation period, and as in the second embodiment, the total cultivation period is adjusted by adjusting the nursery period. You may adjust the

  For example, when a plant group is a plant seeded on a predetermined area in a plant factory on the same day, and a plurality of plant groups are grown in the plant factory, the total cultivation period by the above process for each plant group By continuously making adjustments, it is possible to continuously maximize the profitability of plant factories and the like. In addition, it is possible to minimize the fluctuation range of the profitability (profit rate) of each plant group in a plant factory or the like, and it is possible to stabilize the profitability.

  As described above, according to the plant production method of the present invention, the weight of the plant to be harvested is controlled within the desired range (within the specification) even when there is variation in plant growth (growth rate) in a plant factory or the like. Production stability can be improved. Therefore, there is an advantage that sales can be forecasted and a sales plan can be made (for example, a plan after one month three weeks after sowing can be made). For this reason, the method for producing a plant of the present invention is particularly advantageous in the case of contract sales and the like.

  In adjustment of the total cultivation period, information on future market (demand situation) may be fed forward to the profit margin diagram. For example, the information such as the price of bags decreases and the price of weight sale goes up after one week is reflected in λ (the ratio of the price per weight of weight sale item to the price per weight of sale item). You may leave it. Further, by performing feedback control on parameters with fluctuations such as the purchase rate P, it is possible to improve the profitability with higher accuracy.

(system)
FIG. 2: is a schematic diagram which shows an example of the system used for the production method of the plant of this invention.

  Referring to FIG. 2 and FIG. 3A, in order to measure the leaf area, for example, an imaging device group (MPI: 30) comprising 30 imaging devices (PI: Plant Imager) comprising an ultra-small PC and a camera Multi Plant Imager) is used. MPI is capable of imaging a total of 500 plants. In addition, since monitoring a leaf area in the main cultivation step requires a large area and a complicated imaging device, there is also an advantage that when monitoring the leaf area in a seedling raising process, the device configuration such as the imaging device can be simplified.

  Image data obtained by MPI is transmitted to, for example, a main PC for analysis and a file server for data storage (or NAS: network hard disk) via a wireless LAN access point and a HUB. Note that transmission of image data is not limited to wireless transmission in particular, and may be implemented by wired transmission.

  Then, by performing individual recognition and image processing (leaf area measurement) on the images of individual plants obtained by MPI in the main PC, it is possible to measure leaf areas of individual plants (see FIG. 3 (b)). Next, the main PC calculates an estimated value of the weight of each individual plant (raw weight of the above-ground part) from the measured value of the leaf area.

  Referring to FIG. 7, as shown in FIG. 7 (b), the measured values of the leaf area Li of the individual plants measured by the image analysis process are as shown in FIG. 7 (a). It can be seen that there is a correlation (correlation coefficient R = 0.87) to the measured value of the weight (raw weight of the ground part). Therefore, the estimated value of the weight of each plant can be calculated from the measured value of the leaf area using a calibration curve as shown in FIG. 7 (a).

  Furthermore, the main PC constructs an algorithm for determining the growth rate of the plant group (weight prediction value of the plant group at the end of a certain total cultivation period) based on weight data etc. of individual plants obtained as described above. Do.

  On the main PC, an algorithm for determining the profit margin obtained by the production and sales of plant groups and a profit maximization algorithm for finding the optimum harvest period etc. that maximizes the profit margin (Fig. 3 (c)) are implemented. ing. The profit maximization algorithm calculates the optimal harvest date. Note that, for example, a function may be implemented on the main PC to alert the plant manager of such an optimal harvest date.

  The profit maximization algorithm has a large number of parameters, which are unique values that differ from plant factory to plant factory. For example, crop variety, power cost, standard cultivation period, etc. Although these precise figures are important for constructing a profit maximization algorithm, the power cost etc. also depend on the weather (for example, the cooling cost on a hot summer day) and it is generally complicated. It is desirable to obtain precise parameter values through precise on-site surveys in conjunction with plant factory operation companies.

  The above-described system may include a light source that emits light for cultivating a plant, and a light source control unit that controls lighting of the light source. In addition, the system may be equipped with an air conditioning facility that controls the humidity and temperature in the space that accommodates a plant, a culture facility that supplies a culture medium for plant cultivation, and the like.

  A light source is comprised from LED, a fluorescent lamp, etc., and irradiates the light of the wavelength required for the growth of a plant. The light source may be a light source emitting light of a fixed wavelength or a light source emitting light of a plurality of wavelengths. A light source capable of controlling the wavelength of light to be irradiated is preferably used. It is also known that the growth of plants is influenced by the wavelength of light to be irradiated, and the wavelength of light is appropriately selected.

  In the plant factory, the time corresponding to "night" is dark in the plant factory. For this reason, in order to obtain a clear plant image in a time corresponding to "night", it is necessary to turn on the LED lighting for cultivation (light source). However, the LED for cultivation is relayed by the LED proof control device. It is preferable to control the lighting of the proof not to interfere with the growth of plants (see FIG. 2).

  In addition, as a culture medium of a plant, if it is a culture medium which can grow a plant (main cultivation), it will not be specifically limited, For example, various well-known culture media used for hydroponic cultivation etc. can be used. The cultivation medium is housed, for example, in a cultivation container provided with a recording medium for recording identification information for identifying a transplanted plant. The MPI or main PC can perform individual recognition of a plant by reading identification information of such a recording medium.

  The plurality of cultivation containers are placed, for example, on a cultivation rack provided with a plurality of shelf plates with a predetermined gap therebetween. The above-described system may further include a transport device or the like that transports the cultivation container between the plurality of shelf boards.

  Hereinafter, specific examples of the method for producing a plant of the present invention (in particular, adjustment of the total cultivation period) will be described by way of embodiments.

First Embodiment
In the present embodiment, the total cultivation period is adjusted by adjusting the main cultivation period.

  In the present embodiment, for example, the following formula (2) is used as a formula of the profit ratio Y used to adjust the main cultivation period.

Each symbol in the said Formula (2) is as follows.
Y (t, w ^* , λ): Per share of plant (/ stock)
w ^* : Threshold weight (g) [minimum value of bag-packed weight]
r ^* : Percentage of shares with a weight of w ^* or more (bag-selling stocks) (/ stock)
λ: Ratio of price per weight of weight sale item (cut vegetables etc.) to price per weight of bag sale item
<W>: Average weight (g) of stocks with weight less than w ^* (weight-selling stocks)
P: The rate at which consumers buy bag-selling products Purchase rate α: Fixed cost (In the case of a fixed number of sowings, all except utility costs are included) (/ stock)
β: The cost of utilities in the planting and raising process (from sowing to planting) for each strain per day per day (/ (day, stock))
γ: The cost of utilities in the main cultivation process (from fixed planting to harvest) for each share per day (/ (day, stock))
t ₁ is the greening period (day) [period from seeding to transplantation]
t ₂ is the seedling raising period (day) [period from transplanting to fixed planting]

  Here, <W> can be calculated, for example, using the following equation (4). In the following formula (4), σ (t) is the standard deviation of W (t).

Further, r ^* can be calculated, for example, using the following equation (5).

  P can be calculated, for example, using the following equation (6). In equation (6), w 'is the minimum weight standard that a consumer sees an actual commodity (plant) and purchases 100%.

The relationship between the threshold weight w ^* of the plant of the above formula (6) and the purchase rate P is shown in the graph of FIG. In addition, in FIG. 4, the parameter of Formula (6) is a = 0.02, b =-0.5, w '= 75 (g). In FIG. 4, it is shown that if the threshold weight w ^{* is set} to w ′ (in FIG. 4, w ′ = 75 g) or more, the purchase rate P of the bagged products becomes 100%.

  In the present embodiment, the optimum total cultivation period (optimum cultivation period) of the plant group can be determined based on the graph of the profit ratio Y of the above-mentioned formula (2) as shown in FIG.

In FIG. 9, W _max = 178.25 (g), W ₁ = 0.15 (g), and K = 0.20 in the above equation (1), and α in the above equation (2). = 0.552, β = 0.00082, γ = 0.00558, λ = 0.30, t 1 = 6 ( _{day) is} a graph when set t 2 = 14 and (day). In addition, c. v. The (coefficient of variation) was 0.234. And in FIG. 9, the optimal value (optimal cultivation period) of the total cultivation period t in case threshold weight w ^* is 75 g is 47 days, and the profit ratio Y at that time is 2.259 (25.9%) Met.

  By adjusting the main cultivation period (adjusting the total cultivation period at the stage of the main cultivation step) based on the optimum cultivation period, it becomes possible to realize equal growth among the plant groups (FIG. 5 ( see a) and (b)). That is, when main cultivation is started in the same raising period (transplanting to the cultivation room on the same day), adjustment of the main cultivation period (period from planting to harvesting) allows the plant to have a desired weight. Harvesting is possible (see FIG. 5 (b)).

In FIG. 5 (a), _{W 0} is the time of sowing weight (g) [the weight of the plant (seed) at the time of t = 0]. Further, _{W 2} is [when porting to cultivation room _(t 1 + _{t 2} elapsed time: FIGS. 5 (a) At 20 days after a lapse) Plant weight (planting seedlings) in] planting seedling weight (g) a. Here, t ₂ is the nursery period (day) [period from the transplantation into the nursery chamber to transplantation into a cultivation room (planting)].

  In the present embodiment, by adjusting the total cultivation period (main cultivation period) according to the variation of the seedling growth index, the average value of the profit rate of the plant group compared to the conventional method (see FIG. 10) Y> is stabilized, and production stabilization is realized (see FIG. 11). In addition, the horizontal axis in FIG. 10 and FIG. 11 has shown the working days of the plant factory. FIG. 10 and FIG. 11 show, for example, how many days after the end of MPI measurement that each plant group sown regularly was harvested when a fixed amount of plant group was sown regularly for 100 days. There is. As described above, by continuously performing adjustment of the total cultivation period for each plant group sowed and cultivated regularly, the profitability of each plant group site etc. can be maximized. In addition, it is possible to minimize the fluctuation range of the profitability (profitability) of each plant group, and it is possible to stabilize the profitability.

Second Embodiment
The second embodiment differs from the first embodiment (in which the total cultivation period is adjusted by adjusting the main cultivation period), in that the total cultivation period is adjusted by adjusting the nursery period. The other points are basically the same as those of the first embodiment, and thus redundant description will not be repeated.

  In the present embodiment, for example, the following formula (3) is used as a formula of the profit ratio Y used to adjust the cultivation period.

  In the present embodiment, the optimum total cultivation period (optimum cultivation period) of the plant group can be determined based on the graph of the profit ratio Y of the above equation (3) as shown in FIG.

In FIG. 12, W _max = 178.25 (g), W ₁ = 0.15 (g), and K = 0.20 in the above equation (1), and α in the above equation (2). = 0.552, β = 0.00082, γ = 0.00558, which is a graph of when lambda = _0.30, is set t 3 = 20 and (day). In addition, c. v. The (coefficient of variation) was 0.234. And in FIG. 12, the optimum value (optimum cultivation period) of the total cultivation period t when the threshold weight w ^* is 75 g is 50 days, and the profit ratio at that time is 0.303 (30.3%) there were.

  By adjusting the seedling raising period based on this optimum cultivation period (adjusting the total cultivation period at the stage of the seedling raising process) (see FIG. 6 (a)), the same (without the need for adjustment of the main cultivation period) Even if harvested in the main cultivation period, it is possible to realize equal growth between plant groups different in growth (see FIG. 6 (b)). The number of days from sowing of plant groups A to C until planting of seedlings was 20-4 days for plant group A, 20 days for plant group B, and 20 + 11 days for plant group C.

Incidentally, in FIG. 6 (b), _{W 3} is at harvest weight (g) [the weight of the plants in the harvest time (t = 40 days + adjustment period α date when the elapsed]].

  In the present embodiment, by adjusting the total cultivation period (seed raising period) according to the variation of the seedling growth index, the average value of the profit rate of the plant group compared with the conventional method (see FIG. 13) <Y Is stabilized, and production stabilization is realized (see FIG. 14). In addition, the horizontal axis in FIG. 13 and FIG. 14 has shown the working days of the plant factory. FIG. 13 and FIG. 14 show, for example, how many days after the end of MPI measurement that each plant group sown regularly was harvested when a fixed amount of plant group was sown regularly for 100 days. There is. As described above, by continuously performing adjustment of the total cultivation period for each plant group sowed and cultivated regularly, the profitability of each plant group site etc. can be maximized. In addition, it is possible to minimize the fluctuation range of the profitability (profitability) of each plant group, and it is possible to stabilize the profitability.

  It should be understood that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is indicated not by the above description but by the claims, and is intended to include all the modifications within the meaning and scope equivalent to the claims.

Claims (8)

Planting a seed of a group of plants consisting of at least one plant, sprouting and growing to obtain seedlings;
A seedling raising process, wherein fixed seedlings are obtained by transplanting the seedlings in a nursery room and growing them;
And a main cultivation step of harvesting the planted seedlings after transplanting them into a cultivation room and growing them, and producing the plant,
Collecting data of weights at multiple time points of the raising step for individual plants constituting the group of plants;
From the collected weight data, a total of a greening period which is a period to carry out the greening step, a breeding period which is a period to carry out the seedling raising step, and a main cultivation period which is a period to carry out the main cultivation step Create a relational expression between the total cultivation period, which is the period, and the weight of the plant group,
The plant production method, wherein the total cultivation period is adjusted based on the relational expression such that a proportion of plants having a weight within a predetermined range among plants to be harvested is optimized for the plant group. The relational expression, by fitting the following equation (1) to the weight of the data is a formula obtained by determining the coefficients K, W ₁ on the Growth of the following formulas (1), according to claim 1 Plant production method.

[In the formula (1),
t is the total cultivation period (day),
t ₁ is the greening period (day),
W (t) is an average value of the weight of the plant group when the total cultivation period t (day) has passed,
W _max is the assumed maximum weight (g) of the plant,
W ₁ is the weight (g) of the seedling of the plant,
K is the growth rate. ]   The method for producing a plant according to claim 1, wherein the data of weight is obtained by estimation based on a measurement value of leaf area. To the ratio of the price per plant weight above the threshold weight which is the minimum value of the weight of plants sold in bags among the plant group and the price per plant weight below the threshold weight among the plant group On the basis of which the profit margin obtained by the production and sale of said plant groups is maximized
The method for producing a plant according to any one of claims 1 to 3, wherein the proportion of plants having a weight within a predetermined range among the plants to be harvested is optimized for the group of plants.   The method for producing a plant according to any one of claims 1 to 4, wherein the total cultivation period is adjusted by adjusting the main cultivation period. Adjusting the total cultivation period by adjusting the main cultivation period;
The method for producing a plant according to claim 4, wherein the main cultivation period is adjusted based on the following formula (2) so that the profit margin is maximized.

[In formula (2),
Y (t, w ^* , λ) is the profit ratio per plant (/ strain),
w ^* is the threshold weight (g),
r ^* is the ratio (/ stock) of shares (bag-selling stocks) whose weight is w ^* or more,
λ is the ratio of the price per weight of the heavy sale item to the price per weight of the bag sale item,
<W> is the average weight (g) of stocks less than w ^* (weight-selling stocks),
P is the purchase rate, which is the rate at which consumers buy bag-selling products,
α is fixed cost (/ stock),
β is the utility cost (/ (day, stock)) in the greening step and the seedling step for each strain per day per day,
γ is the cost of utilities (/ (day, stock)) in the main cultivation process per share per day,
t ₁ is the greening period (day),
t _2, said a nursery period (day). ]   The method for producing a plant according to any one of claims 1 to 4, wherein the total cultivation period is adjusted by adjusting the nursery period. Adjusting the total cultivation period by adjusting the nursery period;
The method for producing a plant according to claim 4, wherein the main cultivation period is adjusted based on the following formula (3) such that the profit margin is maximized.

[In formula (3),
Y (t, w ^* , λ) is the profit ratio per plant (/ strain),
w ^* is the threshold weight (g),
r ^* is the percentage of stocks with a weight of w ^* or more (bag-selling stocks) (/ stock)
λ is the ratio of the price per weight of the heavy sale item to the price per weight of the bag sale item,
<W> is the average weight (g) of stocks less than w ^* (weight-selling stocks),
P is the purchase rate, which is the rate at which consumers buy bag-selling products,
α is fixed cost (/ stock),
β is the utility cost (/ (day, stock)) in the greening step and the seedling step for each strain per day per day,
γ is the cost of utilities (/ (day, stock)) in the main cultivation process per share per day,
t _3, the is present cultivation period (day). ]