An observation device for evaluating in situ absorption of fertilizer nutrients by crops

Abstract

The utility model discloses a kind of observation devices for in-situ evaluation crop absorption fertilizer nutrient, from below to above sequentially include solution collection layer, agar layer, soil layer and gel layer;Wherein soil layer is inserted with first ion concentration sensor, solution collection layer is inserted with second ion concentration sensor.The utility model directly determines nutrient concentration (such as potassium, nitrogen ion) in soil layer and solution collection layer by ion concentration sensor, compared with the mode of traditional determination nutrient concentration, without destroying crop or harvesting plant, realize dynamic, continuous in-situ evaluation.Determination nutrient content in soil extract (not direct soil), avoid the error caused by traditional method because of soil uneven, significantly improve data accuracy.

Description

Technical Field

[0001] This utility model relates to the field of fertilization, and in particular to an in-situ observation device for evaluating crop nutrient absorption. Background Technology

[0002] Plant roots are not only the main organs for water and nutrient absorption but also important sites for the synthesis of various hormones, organic acids, and amino acids. The traditional method for calculating crop nutrient use efficiency involves setting up unfertilized and fertilized zones, calculating the nutrient absorption in the fertilized zone minus the nutrient absorption in the unfertilized zone, and then dividing by the amount of fertilizer nutrients artificially applied to the soil. This traditional method cannot evaluate the crop's utilization efficiency of a specific fertilizer in situ; it requires measuring the nutrient content after harvesting the crop. Typically, it can only measure the nutrient use efficiency of a single growth stage of the plant at a time. Therefore, it requires removing the plant and collecting soil samples from both unfertilized and fertilized zones for nutrient testing. Since the absorption efficiency of different nutrients varies at different growth stages, testing the nutrient use efficiency of different plants at different growth stages is time-consuming, labor-intensive, and prone to significant errors due to individual plant differences. Therefore, improvements are needed. Currently, no methods or devices for in-situ evaluation of crop nutrient absorption efficiency have been reported. In order to evaluate the efficiency of crop nutrient absorption in situ without damaging the crop, this utility model introduces a device for in situ determination of crop nutrient absorption efficiency. Utility Model Content

[0003] To address the aforementioned technical problems, this utility model proposes an in-situ observation device for evaluating crop nutrient uptake by fertilizer.

[0004] The objective of this utility model is achieved through the following technical solution:

[0005] An in-situ observation device for evaluating crop nutrient uptake includes, from bottom to top, a solution collection layer, an agar layer, a soil layer, and a gel layer; wherein a first ion concentration sensor is inserted into the soil layer, and a second ion concentration sensor is inserted into the solution collection layer.

[0006] In a further improvement, the solution collection layer includes a collection basin that is closed at the bottom and open at the top, with an insertion hole on the side of the collection basin for inserting a second ion concentration sensor.

[0007] In a further improvement, the upper part of the collecting basin is a frustum-shaped cone, wider at the bottom and narrower at the top, and the collecting basin is made of transparent material.

[0008] In a further improvement, the agar layer includes a cylindrical third growth basin filled with agar, a mesh surface fixed to the bottom of the third growth basin, and the third growth basin is made of transparent material.

[0009] In a further improvement, the soil layer includes a cylindrical second growth basin that is open at both ends, with soil inside the second growth basin; a water inlet pipe is connected to the upper part of the second growth basin; the second growth basin and the third growth basin are integrally formed; and the second growth basin is made of transparent material.

[0010] In a further improvement, the gel layer includes a cylindrical first growth basin filled with gel, a mesh surface fixed to the bottom of the first growth basin, and the first growth basin is made of transparent material; a porous water layer is formed between the gel and the top of the soil.

[0011] As a further improvement, elastic sealing rings are fitted at the junctions of the solution collection layer and the agar layer, as well as at the junctions of the soil layer and the gel layer.

[0012] In a further improvement, the sides of the soil layer and the solution collection layer are respectively provided with insertion holes for the first ion concentration sensor and the second ion concentration sensor.

[0013] A further improvement is that the diameter of the socket is 1 cm.

[0014] The beneficial effects of this utility model are as follows:

[0015] This invention directly measures nutrient concentrations (such as potassium and nitrogen ions) in the soil and solution collection layers using an ion concentration sensor. Compared to traditional methods of nutrient concentration measurement, it eliminates the need to damage crops or harvest plants, enabling dynamic and continuous in-situ evaluation. By measuring the nutrient content in the soil extract (rather than directly measuring the soil), it avoids errors caused by soil inhomogeneity in traditional methods, significantly improving data accuracy. The gel and solution collection layers are made of transparent materials, allowing direct observation of root growth and simultaneous analysis of the relationship between absorption efficiency and root development in conjunction with nutrient data. The device employs a layered structure design, with clearly defined functions for the gel, soil, agar, and solution collection layers. The gel layer supports early root growth; the soil layer provides a fertilization environment; the agar layer stabilizes the soil and allows the extract to permeate; and the solution layer collects leached nutrients for easy sensor detection. This device is simple to operate and low in cost. Its modular design facilitates disassembly and reuse; it requires only conventional sensors and transparent containers, eliminating the need for complex equipment. This device has a wide range of applications and is suitable for studying the utilization efficiency of various nutrients (such as nitrogen ions and potassium ions) in a variety of crops (such as rice and wheat). It overcomes the limitations of traditional destructive sampling, achieving non-destructive, real-time, and high-precision in-situ monitoring while also allowing for root growth observation, providing an efficient and convenient tool for fertilization efficiency research. Attached Figure Description

[0016] The present invention will be further described with reference to the accompanying drawings, but the content of the drawings does not constitute any limitation on the present invention.

[0017] Figure 1 This is a schematic diagram of the overall structure of this utility model.

[0018] Among them, 1 is the gel layer, 11 is the first growth basin, 2 is the soil layer, 21 is the second growth basin, 3 is the agar layer, 31 is the third growth basin, 4 is the first ion sensor, 5 is the elastic sealing ring, 6 is the solution collection layer, 61 is the collection basin, 7 is the second ion sensor, and 8 is the water inlet pipe. Detailed Implementation

[0019] To make the purpose, technical solution and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and examples.

[0020] The specific embodiments of this utility model will now be described with reference to the accompanying drawings.

[0021] Example 1

[0022] The apparatus consists of a gel layer, a fertilized soil layer, an agar layer supporting the soil, and a solution collection layer (root observation layer). Both the gel layer and the solution collection layer are transparent, and both the fertilized soil layer and the agar layer supporting the soil are wrapped in transparent material to facilitate observation of plant root growth by researchers or operators.

[0023] An agar layer supporting the soil is placed on top of a solution collection layer, a soil fertilization layer is placed on top of the agar layer supporting the soil, and a gel layer is placed on top of the soil fertilization layer. Plants are planted in the gel layer, and as the plant's roots grow, they gradually penetrate from the gel layer into the soil fertilization layer, the agar layer supporting the soil, and the solution collection layer.

[0024] In a preferred embodiment, a small hole with a diameter of approximately 1 cm is provided on the side wall at the bottom of the fertilized soil layer and on the side walls on both sides of the bottom of the solution collection layer, allowing the soft needle of the ion concentration sensor to enter the device, thereby detecting the residual nutrient content in the soil and the ion concentration in the soil leachate in situ. The bottom of the soil layer is located above the agar layer supporting the soil; the bottom of the solution collection layer is located 1 cm away from the bottom of the device.

[0025] In this embodiment, the solution collection layer includes a collection basin, a plant growth nutrient solution, and an ion concentration sensor. The collection basin is a combination of a transparent frustum and a flat cylinder, open at the top and sealed at the bottom. Each of the two side walls at the bottom of the collection basin has a small hole approximately 1 cm in diameter to allow the soft needle of the ion concentration sensor to enter the device. The collection basin contains the plant growth nutrient solution, which is primarily a soil extract that has seeped downwards from the fertilized soil layer.

[0026] In this embodiment, the gel layer includes a first growth pot, a mesh surface, and the gel. A hydroponic transparent medium method is used, with the gel serving as the initial root growth and observation component. The first growth pot is a transparent cylindrical body open at both ends. The gel is mixed with an appropriate amount of water and nutrient solution, heated to dissolve, and then poured into the growth pot. The lower end of the first growth pot has a mesh surface that supports the gel layer. Seeds or seedlings are planted in the transparent medium, ensuring that the roots can fully contact the medium. The nutrient solution is determined by the nutrients required by the crop being grown.

[0027] In a preferred embodiment, the diameters of the joints between the gel layer, the fertilized soil layer, the agar layer supporting the soil, and the solution collection layer are all the same, and adjacent layers are sealed with elastic sealing rings. The elastic sealing rings tighten the connections between the gel layer and the fertilized soil layer, between the fertilized soil layer and the agar layer supporting the soil, and between the agar layer supporting the soil and the solution collection layer, thereby preventing water and fertilizer leakage from the entire underground root system at the junctions of adjacent layers.

[0028] When implementing the above observation device, the width radius of the growth pot is 7.5 cm, and the width radius of the lower part of the collection pot is 10 cm. The heights from top to bottom are as follows: a 4 cm gel layer, a 1.5 cm water layer between the gel layer and the fertilized soil layer (because after watering, the water cannot immediately penetrate all into the soil and will form a water layer on top of the soil; the 1.5 cm gap is designed based on the total weight of the soil, the soil water holding capacity, and the volume of the device to allow sufficient space for the water to slowly penetrate into the soil), a 3.5 cm fertilized soil layer, a 2 cm agar layer supporting the soil, and a 15 cm solution collection layer. A mesh is installed at the bottom of the growth pot with the gel layer. Specifically, first, the bottom of the growth pot containing the gel layer and the fertilized soil layer is simply sealed with plastic wrap or other similar materials. The heated and dissolved agar is poured into the growth pot containing the fertilized soil layer to a thickness of about 2 cm to form an agar layer supporting the soil. According to the selected crop, the appropriate amount of nutrient solution, water, and gel required for its growth is mixed, heated and dissolved, and then poured into the growth pot containing the gel layer. After cooling and solidification, the plastic wrap is removed. Then, the treated 1kg of soil is filled into the growth pots of the fertilized soil layer, and each growth pot is fixed in place with an elastic sealing ring to complete the installation of the device.

[0029] Next, crop seeds or cultivated plant seedlings (such as rice seedlings) are transplanted into the gel layer. Rice is cultivated and managed according to conventional methods, and root growth is observed through the upper gel layer. Before the roots penetrate the soil layer, the nutrient content in the soil layer is detected and recorded using an ion concentration sensor. Once the rice roots have grown to the fertilized soil layer, fertilization and watering are carried out through the water inlet pipe. Fertilizer is dissolved in water and then applied to the soil layer. When the rice roots reach the solution collection layer and the total root length is approximately 20 cm, the nutrient content in the fertilized soil layer and soil extract is detected and recorded using an ion concentration sensor. The efficiency of nutrient absorption by the crop is then evaluated in situ using a formula. The number of roots can be observed through the transparent growing pot containing the gel layer and solution collection layer.

[0030] In this embodiment, taking the evaluation of nitrogen fertilizer absorption efficiency as an example, two groups of devices were used to grow the same rice crop. Both groups used soil from the same source, and considering the influence of soil microorganisms, the selected soil was sterilized. One group received normal fertilization, while the other group received no fertilization, allowing the crops to grow normally. One group received Wg of nitrogen fertilizer, while the other group received no fertilizer. Before fertilization, an ion concentration sensor was used to measure the nitrogen content in the soil of both groups, which was W1g. After the total root length reached approximately 20 cm, the ion concentration sensor was used to detect the nitrogen ion content in the soil extract, and the nitrogen content in the two solutions was measured to be W2 and W'2g, respectively. The ion concentration sensor was also used to detect the residual nitrogen ion content in the fertilized soil layer, and the nitrogen content in the two soils was measured to be W3 and W'3g, respectively. At this point, the nitrogen content absorbed by the two crops was W4 and W'4g, respectively. Therefore, W4 = W + W1 - W2 - W3; W'4 = W'1 - W'2 - W'3. The calculation results of the two devices are compared. The difference between W4 and W'4 is the nitrogen content in the fertilizer absorbed by the crop. The efficiency of the crop in absorbing fertilizer nutrients can be obtained by (W4-W'4) / W*100%. The differences in the root system and aboveground growth of the crops under different treatments of the two devices are combined to evaluate the efficiency of the crop in absorbing fertilizer nutrients in situ.

[0031] In this embodiment, considering the influence of soil microorganisms on changes in soil nutrient content, a control experiment with sterilization and non-sterilization was designed for research. Soil from homogeneous farmland (avoiding recent fertilization) was selected, passed through a 2mm sieve, mixed thoroughly, and then packaged. The sterilized group was sterilized by high-pressure steam at 121℃ for 1 hour, while the non-sterilized group was subjected to the same conditions but without sterilization, only simulating the operation. Each pot contained 500g of soil and 10 seeds of Chinese cabbage were sown, ensuring consistent light / temperature / humidity for both groups. Only deionized water was used for irrigation (consistent irrigation amount and frequency). Seven days later, five mixed soil samples were taken from each pot, passed through a 2mm sieve, and the contents of nitrate nitrogen and ammonium nitrogen in the two soil groups were measured. The results showed that the ammonium nitrogen content in the sterilized group was significantly higher than that in the non-sterilized group, while the nitrate nitrogen content was lower; in the non-sterilized group, the ammonium nitrogen content decreased slightly, while the nitrate nitrogen content increased. To avoid bias caused by differences in the types and quantities of soil microorganisms, all selected soils underwent sterilization treatment.

[0032] In this embodiment, fertilizer is dissolved in water and then applied to the soil layer for fertilization. Experiments showed that when the soil moisture content was about 15% to 20%, the soil extract began to leach out. According to the requirements of this embodiment, the dry weight of the soil used was about 1 kg, so about 200 ml of fertilizer solution was added. Based on the radius of the device, the remaining height of the water layer was about 1.5 cm.

[0033] In this embodiment, the bottom of the device layer was selected to determine the residual nutrient content in the soil. A growth pot identical to the device layer was set up, and approximately 1 kg of soil was added. A small hole with a diameter of about 1 cm was made at the top, middle, and bottom layers. Nitrogen fertilizer solution was added until leaching began. After all the soil extract had leached out, the nitrogen content was measured using an ion concentration sensor. The results showed that the nitrogen content in the bottom soil was higher than in the other two layers. Therefore, the bottom layer was chosen as the location for measuring the residual nutrient content in the soil using an ion concentration sensor.

[0034] In this example, the stability and penetration ability of the agar layer supporting the soil need to be considered, thus requiring the definition of agar concentration and thickness. A grouped experiment with concentration gradients was conducted. 0.6, 0.8, 1.0, 1.2, and 1.4 g of agar powder were added to every 100 ml of water, adjusting the pH between 5.5 and 6.5 to avoid high salt concentrations inhibiting root growth. After boiling and dissolving, the solution was poured into molds, resulting in concentration gradients of 0.6%, 0.8%, 1.0%, 1.2%, and 1.4% (w / v), corresponding to thicknesses of 1.0, 1.5, 2.0, 2.5, and 3.0 cm. A 3.5 cm layer of moist soil was evenly spread on top of the agar layer. The concentration selection was evaluated by the degree of agar layer settling. The time (in days) for 50% of the seedling roots to penetrate the agar layer was observed. After 7 days, the proportion of seedlings that successfully penetrated was counted. The thickness selection was evaluated by comparing the time taken and the proportion of seedlings that penetrated the agar layer in each group. The optimal concentration is 1.0%–1.2% (w / v) with a thickness of approximately 2 cm. If penetration remains difficult, try pre-setting fine holes (1–2 mm in diameter) in the center of the agar layer to guide root growth.

[0035] Agar supports the soil without hindering the free flow of the soil extract between the soil and liquid layers. Rubber gaskets between the sealing ring and the growing pot prevent fertilizer and water leakage, ensuring reliable experimental data. An elastic sealing ring facilitates assembly and disassembly. Observing the roots through the transparent walls of the transparent gel layer and solution collection layer provides a more direct view of root growth.

[0036] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of this utility model and are not intended to limit the scope of protection of this utility model. Although this utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solution of this utility model without departing from the essence and scope of the technical solution of this utility model.

Claims

1. An in-situ observation device for evaluating crop nutrient uptake, characterized in that, From bottom to top, it includes a solution collection layer (6), an agar layer (3), a soil layer (2), and a gel layer (1); wherein a first ion concentration sensor (4) is inserted in the soil layer (2), and a second ion concentration sensor (7) is inserted in the solution collection layer (6).

2. The in-situ observation device for evaluating crop nutrient uptake as described in claim 1, characterized in that, The solution collection layer (6) includes a collection basin (61) that is closed at the bottom and open at the top, and the side of the collection basin (61) has an insertion hole for the second ion concentration sensor (7) to be inserted.

3. The in-situ observation device for evaluating crop nutrient uptake as described in claim 2, characterized in that, The upper middle part of the collecting basin (61) is a frustum-shaped cone that is wider at the bottom and narrower at the top, and the collecting basin (61) is made of transparent material.

4. The in-situ observation device for evaluating crop nutrient uptake as described in claim 1, characterized in that, The agar layer (3) includes a cylindrical third growth basin (31), which is filled with agar. A mesh is fixed to the bottom of the third growth basin (31), and the third growth basin (31) is made of transparent material.

5. The in-situ observation device for evaluating crop nutrient uptake as described in claim 4, characterized in that, The soil layer (2) includes a cylindrical second growth basin (21) that is open at both ends, and the inside of the second growth basin (21) is soil; the upper part of the second growth basin (21) is connected to a water inlet pipe (8); the second growth basin (21) and the third growth basin (31) are integrally formed; the second growth basin (21) is made of transparent material.

6. The in-situ observation device for evaluating crop nutrient uptake as described in claim 5, characterized in that, The gel layer (1) includes a cylindrical first growth basin (11), which is filled with gel. A mesh is fixed to the bottom of the first growth basin (11), and the first growth basin (11) is made of transparent material. A porous water layer is formed between the gel and the top of the soil.

7. The in-situ observation device for evaluating crop nutrient uptake as described in claim 1, characterized in that, Elastic sealing rings (5) are fitted at the junction of the solution collection layer (6) and the agar layer (3), as well as at the junction of the soil layer (2) and the gel layer (1).

8. The in-situ observation device for evaluating crop nutrient uptake as described in claim 1, characterized in that, The sides of the soil layer (2) and the solution collection layer (6) are respectively provided with insertion holes for the first ion concentration sensor (4) and the second ion concentration sensor (7).

9. The in-situ observation device for evaluating crop nutrient uptake as described in claim 8, characterized in that, The diameter of the socket is 1 cm.

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