Precision irrigation method for factory tomato seedlings based on substrate porosity

Abstract

The present invention belongs to the technical field of tomato seedling cultivation, and relates to a precise watering method for tomato industrialized seedling cultivation based on the porosity of the substrate, comprising the following steps: preparing a seedling cultivation substrate and loading it into a seedling tray, sowing tomato seeds, and setting the porosity of the selected seedling cultivation substrate as x; watering the sown seedling cultivation substrate and keeping it moist until the tomato seeds germinate; after the tomato seeds germinate, using the equation y = 0.49x<supgt;2< / supgt; - 0.28x + 0.12 as a guiding method to quantitatively water the seedling cultivation substrate, where y (L) is the optimal watering amount per liter of the seedling cultivation substrate, until the tomato seedlings meet the requirements for transplantation. The present invention obtains the correlation between the porosity, the watering amount and the strong seedlings, forms a precise irrigation technology that can support the automatic control of the Internet of Things, and realizes the precise irrigation of tomato industrialized seedling cultivation.

Description

Technical Field

[0001] The present invention belongs to the technical field of tomato seedling raising, and particularly relates to a precise irrigation method for tomato industrialized seedling raising based on substrate porosity. Background Art

[0002] China is the country with the largest tomato planting area and the highest output in the world. Before planting tomatoes, intensive seedling raising can shorten the planting cycle of tomatoes, promote early maturity and market of tomatoes, thus improving production efficiency. Cultivating high-quality and strong seedlings is the basis for obtaining a bumper harvest of tomatoes. The existing technologies mainly focus on the research of the physical and chemical property ratio of the substrate, nutrient supply and pest control. The key link to obtain high-quality seedlings is to control the precise watering time and watering amount during seedling cultivation. At the same time, precise irrigation technology can save resources, reduce space humidity, reduce the occurrence of diseases, and support the operation of the Internet of Things technology. Therefore, how to formulate a scientific, reasonable and feasible irrigation method during the seedling raising process is a direction worthy of research by those skilled in the art. Summary of the Invention

[0003] In order to solve the problems existing in the above-mentioned prior art, the present invention provides a precise irrigation method for tomato industrialized seedling raising based on substrate porosity, researches the correlation between the porosity of the seedling raising substrate, the watering amount and strong seedlings, and forms a precise irrigation technology that can support the automatic control of the Internet of Things to obtain high-quality and strong seedlings.

[0004] The specific technical solution adopted by the present invention is as follows:

[0005] A precise irrigation method for tomato industrialized seedling raising based on substrate porosity, which is characterized by including the following steps:

[0006] S1. Sowing: Prepare the seedling raising substrate and load it into the seedling raising tray, and sow tomato seeds. The porosity of the selected seedling raising substrate is set as x;

[0007] S2. Water the sown seedling raising substrate and keep it moist until the tomato seeds germinate;

[0008] S3. Use a soil moisture sensor to measure the relative water content of the seedling raising substrate. When the relative water content of the seedling raising substrate reaches 54-66%, water it, or water it when the leaves of the tomato seedlings begin to wilt. When the relative water content of the seedling raising substrate is the relative water content at the time of watering + (4-5), issue a watering warning, and use the equation as the guiding method to quantitatively water the seedling raising substrate. The equation is y = 0.49x 2 -0.28x + 0.12, where y (L) is the optimal watering amount per liter of the seedling raising substrate. Then the watering amount (L) of the seedling raising substrate with the same porosity = total volume of the seedling raising substrate (V) * (0.49x 2-0.28x + 0.12); until the tomato seedlings meet the requirements for transplanting.

[0009] In the step S1 described above, the seedling-raising substrate includes one or a mixture of two of garden soil and soilless seedling-raising substrate.

[0010] The formula of the soilless seedling-raising substrate includes peat, perlite, and vermiculite with a volume ratio of 2:1:1.

[0011] In the step S2 described above, the seedling-raising substrate after sowing is watered to a saturated state, and under the moisturizing state, wait until more than 85% of the tomato seeds germinate.

[0012] In the step S1 described above, 0.45 ≤ x ≤ 0.69.

[0013] In the step S1 described above, x = 0.56.

[0014] In the step S3 described above, a soil moisture sensor is used to measure the relative water content of the seedling-raising substrate; when the relative water content of the seedling-raising substrate reaches 65 - 66%, a watering warning is given, and when the relative water content of the seedling-raising substrate reaches 61 - 62% or the leaves of the tomato seedlings begin to wilt, watering is carried out.

[0015] The beneficial effects of the present invention are:

[0016] The present invention prepares a seedling-raising substrate, sows tomato seeds into the seedling-raising substrate, conducts initial saturated irrigation and moisturizing on the seedling-raising substrate after sowing to ensure the smooth germination of tomato seeds. When the watering standard is reached after emergence, according to the equation y = 0.49x 2 -0.28x + 0.12, quantitative watering is carried out on the seedling-raising substrate, where y (L) is the optimal watering amount per liter of the seedling-raising substrate, and x is the porosity of the seedling-raising substrate. The present invention provides guidance on the accurate watering amount for tomato seedling raising using seedling-raising substrates with different porosities, can quickly determine the optimal watering amount suitable for the current seedling-raising substrate, significantly improves the proportion of high-quality and strong seedlings, effectively saves resources, reduces the space humidity, reduces the occurrence of diseases, and supports the operation of the Internet of Things technology, providing data support for the industrialized seedling raising of tomatoes. Description of the Drawings

[0017] Figure 1 It is a scree plot of principal component analysis. Detailed Embodiments

[0018] The present invention will be further described below in combination with experiments, drawings, and specific embodiments:

[0019] I. Experimental Design

[0020] 1. Experimental Materials and Methods Tomato was selected as the experimental material, and plug trays were used for seedling raising. Four experimental substrates with different porosities were selected, namely garden soil, soilless seedling substrate (peat: vermiculite: perlite = 2:1:1), 1 / 2 garden soil + 1 / 2 soilless seedling substrate, and 1 / 3 garden soil + 2 / 3 soilless seedling substrate. Four different water content treatments were set for each experimental substrate, with a total of 16 treatments. The specific treatments are shown in Table 1 below. After preparing the experimental substrates according to the experimental design, fill the plugs, weigh them, and ensure that the volumes of the experimental substrates filled in the plug trays with the same experimental substrate are the same. After sowing, unified management was carried out. Until before emergence, unified watering management (water thoroughly) was carried out, and the number of watering times and the amount of water were recorded.

[0021] Before sowing the seedlings, the volumes and porosities of the four experimental substrates were measured uniformly. The measurement method was calculated according to the method in the reference (Wang Yingmei, Shen Yaodong, Yang Zongxian, etc. Changes in the physical and chemical properties of organic fermentation substrates and their effects on the emergence of melon seedlings [J]. Journal of Tarim University, 2022, 34(03): 53 - 60.). The porosities of the four experimental substrates, namely garden soil, soilless seedling substrate, 1 / 2 garden soil + 1 / 2 soilless seedling substrate, and 1 / 3 garden soil + 2 / 3 soilless seedling substrate, calculated were 0.45, 0.69, 0.56, and 0.61 respectively.

[0022] The soil water content was calculated through the porosity. 100% water volume = experimental substrate volume × porosity × 100%, 90% water volume = experimental substrate volume × porosity × 90%, 80% water volume = experimental substrate volume × porosity × 80%, 70% water volume = experimental substrate volume × porosity × 70%. A 50 - hole seedling tray with a single - hole top side length × bottom side length × height = 5×3×6 cm was selected, and the single - hole volume was about 60 ml. Then, the experimental substrate required to fill the seedling tray was 50×60 ml = 3 L. The water content gradients of different experimental substrates are shown in Table 1 below.

[0023] Table 1 Water content gradients of different experimental substrates

[0024]

[0025] Before emergence, water thoroughly (100% water volume). After more than 85% of the tomato seeds emerged in each experimental substrate, watering was carried out according to the water content gradients of 100%, 90%, 80%, and 70% respectively according to different porosities. The experimental design is shown in Table 2 below. When watering each treatment, water according to the specific conditions of different treatments of different experimental substrates, that is, water again when the leaves of the crop begin to show wilting, which needs to be determined according to the actual situation (Note: There will be differences in the watering time for each treatment).

[0026] Table 2 Experimental design

[0027]

[0028] 2. Measurement of indicators

[0029] 2.1 Measurement of growth indicators

[0030] After the seedlings meet the requirements for field planting, measure the plant height, stem diameter, fresh weight of the underground part, fresh weight of the above-ground part, dry weight of the underground part, dry weight of the above-ground part, number of leaves, root diameter, root length, and SPAD value (relative chlorophyll content) of the plants in each treatment. Calculate the strong seedling index = (stem diameter / plant height + dry weight of the underground part / dry weight of the above-ground part) * (dry weight of the underground part + dry weight of the above-ground part)

[0031] 2.2 Statistics of the watering frequency and amount of water for each treatment:

[0032] Record the unified amount of water before emergence, and record the number of times of watering according to the specified amount of water after emergence.

[0033] 3. Data analysis

[0034] Summarize the data of each index obtained from each treatment, analyze using Excel, and perform principal component analysis using SPSS 22.0.

[0035] II. Test results

[0036] 1. Principal component analysis of main agronomic traits

[0037] Through principal component analysis of 10 main agronomic traits of tomato seedlings in 16 treatments, and using SPSS software for KMO and Bartlett tests, it can be seen from Table 1 that: KMO is 0.625, greater than 0.6, meeting the prerequisite requirements for principal component analysis, indicating that the data can be used for principal component analysis research. And the data passes the Bartlett sphericity test (p < 0.05), indicating that the research data is suitable for principal component analysis.

[0038] Table 3 KMO and Bartlett tests

[0039]

[0040] Figure 1 It is the scree plot for principal component analysis. The scree plot can help determine the optimal number of principal components. The abscissa in the figure represents the number of principal components, and the ordinate represents the eigenvalue. It can be seen that as the number of principal components increases, the eigenvalue gradually decreases. The eigenvalues of the first 3 principal components are all greater than 1, and the connection is relatively steep, that is, the first 3 principal components contribute the most to explaining the variables. Therefore, extract the first 3 principal components.

[0041] As can be seen from Table 4, the variance interpretation rates of the three principal components are 48.798%, 16.025%, and 13.697% respectively, and the cumulative variance interpretation rate is 78.520%. In addition, a total of three principal components were extracted in this analysis, and their corresponding weighted variance interpretation rates, that is, weights, are as follows: 48.798 / 78.520 = 62.15%; 16.025 / 78.520 = 20.41%; 13.697 / 78.520 = 17.44%.

[0042] Table 4 Variance Interpretation Rate Table

[0043]

[0044] As can be seen from Table 5: The communality values corresponding to all research items are higher than 0.4, which means that there is a strong correlation between the research items and the principal components, and the principal components can effectively extract information. After ensuring that the principal components can extract most of the information of the research items, then analyze the corresponding relationship between the principal components and the research items (when the absolute value of the loading coefficient is greater than 0.4, it indicates that there is a corresponding relationship between this item and the principal component).

[0045] Table 5 Loading Coefficient Table

[0046]

[0047]

[0048] When using the principal component scores for comprehensive evaluation, it is necessary to use the "linear combination coefficient matrix" to establish the relationship equation between the principal components and the research items. As shown in Table 6 below, based on the standardized data, the relationship expression is established as follows:

[0049] Component Score 1 = 0.213 * SPAD value + 0.264 * plant height + 0.390 * stem diameter + 0.358 * number of leaves + 0.422 * aboveground fresh weight + 0.393 * underground fresh weight + 0.410 * aboveground dry weight + 0.238 * underground dry weight - 0.215 * dry root-shoot ratio + 0.048 * fresh root-shoot ratio;

[0050] Component Score 2 = 0.404 * SPAD value - 0.343 * plant height - 0.116 * stem diameter + 0.036 * number of leaves - 0.043 * aboveground fresh weight + 0.263 * underground fresh weight - 0.098 * aboveground dry weight + 0.287 * underground dry weight + 0.478 * dry root-shoot ratio + 0.559 * fresh root-shoot ratio;

[0051] Component score 3 = 0.119 * SPAD value + 0.359 * plant height - 0.128 * stem diameter - 0.093 * number of leaves + 0.041 * fresh weight of aboveground part - 0.195 * fresh weight of underground part + 0.057 * dry weight of aboveground part + 0.546 * dry weight of underground part + 0.501 * dry root-shoot ratio - 0.490 * fresh root-shoot ratio;

[0052] And the comprehensive score is calculated by accumulating the product of the variance interpretation rate and the component scores. The calculation formula for the current data is: (48.798 * component score 1 + 16.025 * component score 2 + 13.697 * component score 3) / 78.520;

[0053] Final score = 0.621 * component score 1 + 0.204 * component score 2 + 0.174 * component score 3;

[0054] Table 6 Linear combination coefficient matrix

[0055]

[0056] As can be seen from Table 7, the comprehensive ranking order is C3, C2, C4, C1, B3, B4, A2, D3, A3, A1, D2, A4, D1, D4, B1, B2. Among them, the treatments in group C occupy the top four positions in the ranking, indicating that when the porosity is 0.56, the tomato seedlings grown are the best. In addition, among the treatments in group A, the A2 treatment has the highest score, among the treatments in group B, the B3 treatment has the highest score, among the treatments in group C, the C3 treatment has the highest score, and among the treatments in group D, the D3 treatment has the highest score. This shows that when cultivating strong tomato seedlings with experimental substrates of different porosities, the optimal water content is different, but it is all between 80% and 90% water content.

[0057] Table 7 Comprehensive score table

[0058]

[0059]

[0060]

[0061] The values in parentheses in Table 7 represent negative values, e.g., (1.45) = -1.45.

[0062] 2. Establishment of the equation for the porosity of the unit experimental substrate and the optimal water content

[0063] As can be seen from the results of the principal component analysis, the optimal water content corresponding to the experimental substrates with different porosities for a 1L substrate volume is shown in Table 8 below. Let the porosity be x and the optimal water content be y1 (L), and calculate the regression equation. The obtained equation is y1 = 0.61x + 0.12 (R2 = 0.9632), where the porosity x ranges from 0.45 to 0.69.

[0064] Table 8 Porosity and Optimal Water Content of Test Substrates

[0065]

[0066] 3. Determination of Wilting Coefficient of Tomato Seedlings in Different Test Substrates

[0067] When the emergence rate of tomato seeds reaches over 85%, control the watering until the initial wilting of the seedling leaves (it can resume growth after replenishing water again). Measure the soil water content at this time, which is the water content at the whole-plant wilting, and this soil water content is used as the minimum limit for watering the seedlings. During the measurement, randomly select 5 holes in the same seedling tray treated with different test substrates. After thoroughly watering at sowing, measure the weight of the soil at saturated water. When the emergence rate of tomato seeds reaches over 85%, control the watering until the initial wilting, and then measure the soil weight at this time. Then take them out separately and place them in an oven at 115 °C for drying for 24 h, measure the dry weight of the soil, and then calculate the relative soil water content at the initial wilting. According to the relative soil water content = soil water content / soil saturated water content × 100%, the relative soil water content at the initial wilting = (soil weight at the initial wilting - soil dry weight) / (soil weight at saturated water - soil dry weight) × 100%. The specific calculation results are shown in Table 9 below.

[0068] Table 9 Relative Soil Water Content at the Initial Wilting of Tomato Seedlings with Different Substrate Types

[0069]

[0070] Establish the Equation between the Porosity of the Unit Test Substrate and the Relative Soil Water Content at the Initial Wilting of Tomato Seedlings

[0071] When the substrate volume is 1 L, set the porosity as x and the relative soil water content at the initial wilting as y2 (%), calculate the regression equation, and the obtained equation is y2 = -49.10x + 88.65 (R 2 = 0.9981), where the porosity x ranges from 0.45 to 0.69.

[0072] 4. Establish the Equation between the Porosity of the Unit Volume Test Substrate and the Actual Optimal Watering Amount

[0073] When the substrate volume is 1 L, the actual optimal watering amount = optimal water content - soil water content at wilting = optimal water content - (substrate volume × porosity × relative water content at the initial wilting), as shown in Table 10. Set the porosity as x and the optimal watering amount as y (L), calculate the regression equation, and the obtained equation is: y = y1 - (1 × x × y2) = 0.61x + 0.12 - (1 × x × (-49.10x + 88.65)) = 0.49x 2 - 0.28x + 0.12.

[0074] Table 10 Substrate Porosity and Actual Optimal Watering Volume

[0075] Test substrate type Porosity Optimal watering amount (L) Garden soil 0.45 0.09 Soilless seedling substrate 0.69 0.16 1 / 2 garden soil + 1 / 2 soilless seedling substrate 0.56 0.12 1 / 3 garden soil + 2 / 3 soilless seedling substrate 0.61 0.13

[0076] The relative water content of the test substrate can be measured using a soil moisture sensor, and when the initial wilting of tomato seedlings occurs or the relative water content reaches 54 - 66%, watering is carried out according to the equation y = 0.49x 2 - 0.28x + 0.12

[0077] The preferred ratio of the nursery substrate used in tomato industrialized seedling raising is 1 / 2 garden soil + 1 / 2 soilless nursery substrate, that is, the nursery substrate with a porosity of 0.56

[0078] Example 1. A precise irrigation method for tomato industrialized seedling raising based on substrate porosity, comprising the following steps:

[0079] S1. Sowing: Use a 50 - hole seedling tray for seedling raising, and the single - hole volume of the seedling tray is about 60 ml; prepare healthy garden soil and soilless nursery substrate, mix the healthy garden soil and soilless nursery substrate evenly at a volume ratio of 1:1 to make the nursery substrate, the porosity of the nursery substrate is 0.56, fill the nursery substrate into the holes of the seedling tray, and then sow tomato seeds into each hole; the formula of the soilless nursery substrate includes peat, perlite, and vermiculite with a volume ratio of 2:1:1

[0080] S2. Water the sown nursery substrate to a saturated state, and under the moisturizing state, wait for more than 85% of the tomato seeds to germinate

[0081] S3. Set a soil moisture sensor in the nursery substrate in the seedling tray, give an early warning when the relative water content of the nursery substrate reaches 67%, and water when it is close to 62%. At this time, the leaves of the tomato seedlings begin to show wilting, and use the equation y = 0.49x 2 - 0.28x + 0.12 as a guiding method to quantitatively water the nursery substrate, where y is the actual optimal watering volume per liter of nursery substrate, x is the porosity, y = 0.49x 2 - 0.28x + 0.12 = 0.49×0.56 2 - 0.28×0.56 + 0.12≈0.12 L, then the actual optimal watering volume (L) of the nursery substrate in one seedling tray = total nursery substrate volume (V)*(0.49x 2 - 0.28x + 0.12) y = 3×0.12 = 0.36 L

[0082] Example 2: The difference from Example 1 is that healthy garden soil and soilless seedling-raising substrate are mixed and stirred evenly at a volume ratio of 1:2 to make the seedling-raising substrate. The porosity of the seedling-raising substrate is 0.61. When the relative water content of the seedling-raising substrate reaches 63%, a warning is given. When the relative water content of the seedling-raising substrate is close to 58%, watering is carried out. Then the actual optimal watering amount y per liter of the seedling-raising substrate is y = 0.49x 2 -0.28x + 0.12 = 0.49×0.61 2 -0.28×0.61 + 0.12 ≈ 0.13L. The actual optimal watering amount of the seedling-raising substrate in a seedling tray is 0.13×3 = 0.39L.

[0083] Example 3: The difference from Example 1 is that healthy garden soil is used as the seedling-raising substrate. The porosity of the seedling-raising substrate is 0.45. When the relative water content of the seedling-raising substrate is close to 70%, a warning is given. When the relative water content of the seedling-raising substrate is close to 66%, watering is carried out. Then the actual optimal watering amount per liter of the seedling-raising substrate is y = 0.49x 2 -0.28x + 0.12 = 0.49×0.45 2 -0.28×0.45 + 0.12 ≈ 0.09L. The actual optimal watering amount of the seedling-raising substrate in a seedling tray is 0.09×3 = 0.27L.

[0084] Example 4: The difference from Example 1 is that the soilless seedling-raising substrate is used as the seedling-raising substrate. The porosity of the seedling-raising substrate is 0.69. When the relative water content of the seedling-raising substrate reaches 59%, a warning is given. When the relative water content of the seedling-raising substrate is close to 55%, the watering standard is reached. Then the optimal water content y per liter of the seedling-raising substrate is y = 0.49x 2 -0.28x + 0.12 = 0.49×0.69 2 -0.28×0.69 + 0.12 ≈ 0.16L. The watering amount of the seedling-raising substrate in a seedling tray is 0.16×3 = 0.48L.

[0085] During the conventional tomato seedling-raising process, irrigation depends solely on the subjective judgment of technicians, either watering thoroughly or sprinkling some water to moisten the seedling-raising substrate. However, the present invention breaks the conventional irrigation mode, obtains the correlation among porosity, watering amount and strong seedlings, provides the selection of the optimal porosity for tomato seedling-raising and the guidance of the best watering amount, forms a precise irrigation technology that can support automatic Internet of Things control by controlling different watering amounts for different porosities, realizes precise irrigation for tomato factory seedling-raising, and significantly increases the number of strong seedlings of tomato seedlings obtained from tomato factory seedling-raising, thus significantly improving the economic benefits of factory seedling-raising.

Claims

1. A precise irrigation method for factory tomato seedlings based on substrate porosity, characterized in that, Including the following steps: S1. Sowing: Prepare the seedling-raising substrate and fill it into the seedling tray, and sow tomato seeds. The porosity of the selected seedling-raising substrate is set to x; x = 0.56; S2. Water the sown seedling-raising substrate and keep it moist until the tomato seeds germinate; S3. Use a soil moisture sensor to measure the relative water content of the seedling-raising substrate. Issue a watering warning when the relative water content of the seedling-raising substrate reaches 65 - 66%. Water when the relative water content of the seedling-raising substrate reaches 61 - 62% or when the leaves of tomato seedlings begin to wilt. Use the equation as a guiding method to quantitatively water the seedling-raising substrate. The equation is y = 0.49x 2 - 0.28x + 0.12, where y is the optimal watering amount per liter of the seedling-raising substrate. Then the watering amount of the seedling-raising substrate with the same porosity = total volume of the seedling-raising substrate * (0.49x 2 - 0.28x + 0.12); until the tomato seedlings meet the requirements for transplanting.

2. The precision irrigation method for tomato factory seedling raising based on matrix porosity according to claim 1, characterized in that: In the step S1, the seedling-raising substrate includes one or a mixture of two of garden soil and soilless seedling-raising substrate.

3. The precise irrigation method for tomato industrialized seedling raising based on matrix porosity according to claim 2, characterized in that: The formula of the soilless seedling-raising substrate includes peat, perlite and vermiculite with a volume ratio of 2:1:

1.

4. The precise irrigation method for tomato industrialized seedling raising based on matrix porosity according to claim 1, characterized in that: In the step S2, water the sown seedling-raising substrate to the saturated state, and under the moist state, wait until more than 85% of the tomato seeds germinate.

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