CN111362744A

CN111362744A - Method for stabilizing pH value of plant water culture nutrient solution

Info

Publication number: CN111362744A
Application number: CN202010191242.9A
Authority: CN
Inventors: 周相助; 龚化勤; 汪锐
Original assignee: Fujian Sanan Sino Science Photobiotech Co Ltd
Current assignee: Fujian Sanan Sino Science Photobiotech Co Ltd; Fujian Province Sino Science Biological Co Ltd
Priority date: 2020-03-18
Filing date: 2020-03-18
Publication date: 2020-07-03
Also published as: WO2021185093A1

Abstract

The invention discloses a method for stabilizing the pH value of a plant water culture nutrient solution, which is characterized in that citric acid or citrate is added on the basis of the water culture nutrient solution, and the pH value of the nutrient solution is stabilized by utilizing the buffer property of the citric acid or citrate. The method can keep the pH value of the nutrient solution in the whole growth period of the hydroponic leafy vegetables in the plant factory condition within a safe range without manual intervention, thereby greatly simplifying the planting process.

Description

Method for stabilizing pH value of plant water culture nutrient solution

Technical Field

The invention relates to the technical field of soilless culture of plants, in particular to a method for stabilizing the pH value of a water culture nutrient solution of a plant.

Background

The water culture is nutrient solution culture, the normal growth and development of crops are directly influenced by the pH value in the nutrient solution, and the pH value of the nutrient solution fluctuates due to unbalanced cation and anion content caused by different absorption rates of plant root systems to cations and anions in the nutrient solution, so that the growth and development of the plants are influenced. Therefore, the regulation and control of the pH value of the nutrient solution in soilless culture are of great importance, most of the prior production adopts pH compounds to regulate the pH value of the nutrient solution, the nutrient solution needs to be monitored and manually regulated every day, and the method is complicated and greatly improves the labor cost.

Disclosure of Invention

In view of the above, the technical problem to be solved by the present invention is to provide a method for stabilizing the pH value of a plant hydroponic nutrient solution, which can keep the pH value of the nutrient solution within a safe range without manual intervention during the whole growth cycle of hydroponic leafy vegetables under plant factory conditions, thereby greatly simplifying the planting process.

The invention adopts the specific technical scheme that:

a method for stabilizing pH value of plant water culture nutrient solution is characterized by adding citric acid or citrate on the basis of existent water culture nutrient solution, and utilizing buffer property of citric acid or citrate to stabilize pH value of nutrient solution.

In order to better realize the invention, the content of citric acid or citrate in the nutrient solution formula is 40-120 mg/L.

In order to better realize the invention, the method for stabilizing the pH value of the plant water culture nutrient solution by adding citric acid or citrate can be used for adding citric acid or citrate into the nutrient solution dry powder, the storage mother solution or the culture working solution, so that the concentration of citric acid or citrate in the prepared culture working solution is 40-120 mg/L.

The invention also provides application of the method for stabilizing the pH value of the plant water culture nutrient solution in plant water culture.

The invention has the beneficial effects that:

1. the method for stabilizing the pH value of the plant water culture nutrient solution enables the pH value of the nutrient solution to be stabilized within an ideal range of 5.5-6.5 meeting the plant growth requirement in a water culture process for a long time, reduces the manual intervention and adjustment force, and saves the labor cost;

2. the method for stabilizing the pH value of the plant water culture nutrient solution avoids adding a large amount of acid-base substances by artificially adjusting the pH value, thereby avoiding interference on plant growth;

3. the invention simplifies the operation of nutrient solution regulation and control in the process of water planting, saves labor cost and is convenient for popularization of corresponding plant factory systems.

Drawings

FIG. 1 shows the effect of citric acid at different concentrations on the pH during lettuce cultivation in the Hoagland's nutrient solution;

FIG. 2 shows the effect of citric acid of different concentrations on pH during the cultivation of Chinese cabbage as a Chinese leafy vegetable nutrient solution;

FIG. 3 shows the effect of sodium citrate at different concentrations on pH during lettuce cultivation in garden test hydroponic nutrient solution.

Detailed Description

The present invention will be described in further detail with reference to examples, but the embodiments of the present invention are not limited thereto, and various substitutions and alterations can be made without departing from the technical idea of the present invention as described above, according to the common technical knowledge and the conventional means in the field.

Example 1

The embodiment provides a nutrient solution formula for stabilizing the pH value of a hydroponic vegetable working solution on the basis of a Hoagland nutrient solution formula, wherein each nutrient element in the nutrient solution formula comprises 15.0mmol/L of nitrogen, 6.0mmol/L of potassium, 1.0mmol/L of phosphorus, 5.0mmol/L of calcium, 2.0mmol/L of magnesium, 0.0897mmol/L of iron, 0.00792mmol/L of manganese, 0.00032mmol/L of copper, 0.04627mmol/L of boron, 0.000765mmol/L of zinc, 0.000208mmol/L of molybdenum, 2.0mmol/L of sulfur and 0-160mg/L (excluding 0) of citric acid or citrate.

Using the nutrient solution, lettuce cultivation test is carried out in plant factory under full artificial light environment, 4 treatments are designed, 1 control, namely 5 gradient citric acid concentrations are 0mg/L CK (control), 40mg/L, N2N 1 is 80mg/L, N3 is 120mg/L, N4 is 160mg/L citric acid, and the ratio of citric acid: sodium hydroxide ═ 1: 3 sodium hydroxide was added to adjust the pH of the nutrient solution for each treatment group, with 6 replicates per treatment set. Setting the conductivity of the initial nutrient solution to be about 2.0mS/cm and the initial pH to be 6.0, and in order to monitor the pH autonomous change condition of the nutrient solution from the post-planting to the pre-harvest, the pH value of the nutrient solution is not interfered after the planting, namely the pH is not adjusted, and when the EC of the nutrient solution is reduced to be below 1.7mS/cm, the nutrient solution containing citric acid with corresponding concentration is supplemented.

The daily pH monitoring is shown in FIG. 1, and the results of the experiments show that the pH fluctuation is large in the treatment without citric acid addition (CK, 0mg/L) and small in the control, wherein the pH of the working solution is maintained within the desired range of 5.5-6.5 when the citric acid concentration is 40-120mg/L (N1-N3).

Example 2

The embodiment provides a nutrient solution formula for stabilizing the pH value of a hydroponic vegetable working solution on the basis of a Chinese leafy vegetable nutrient solution formula, wherein each nutrient element in the nutrient solution formula comprises 6.8-7.1mmol/L of nitrogen, 4.9-5.1mmol/L of potassium, 0.95-1.0mmol/L of phosphorus, 1.22-1.28mmol/L of calcium, 0.95-1.0mmol/L of magnesium, 0.12-0.14mmol/L of iron, 0.009-0.01mmol/L of manganese, 0.0002-0.0003mmol/L of copper, 0.048-0.053mmol/L of boron, 0.005-0.0055mmol/L of zinc, 0.0003-0.00033mmol/L of molybdenum, 1.0mmol/L of sulfur, and 0-150mg/L (excluding 0) of citric acid or citrate.

In this case, the cultivation test of pakchoi was carried out in a plant factory in a total artificial light environment, 3 treatments were designed, and 1 control, i.e., 4 gradient citric acid concentrations, i.e., 0mg/L of T1 (control), 100mg/L of T2 (50mg/L, T3) and 150mg/L of T4, were respectively calculated according to the following citric acid: sodium hydroxide ═ 1: 3 sodium hydroxide was added to adjust the pH of the nutrient solution for each treatment group, with 3 replicates per treatment set. Setting the conductivity of the initial nutrient solution to be about 2.0mS/cm, setting the initial pH to be 6.0, and monitoring the pH value of the nutrient solution after field planting to be changed automatically before harvesting, so that the pH value of the nutrient solution is not interfered after field planting, namely the pH value is not adjusted.

The daily follow-up monitoring of pH values after colonization is shown in fig. 2, and the experimental results show that in T1 (control) and T2 (50mg/L citric acid), the pH values are reduced to a lower level (about 5.0) in the early stage of colonization and then increased. The pH value of the solution treated by T4 (150mg/L citric acid) rises to about 7.35 after the solution is planted for 2 days, and then the solution is maintained at a higher level (more than 6.5). After the T3 treatment (100mg/L citric acid) for 2 days of field planting, the pH value rises more and then shows a slow descending trend, and the pH value can be well maintained in an ideal range of 5.5-6.5 from the 8 th day after field planting to before harvesting.

Example 3

The embodiment provides a nutrient solution formula for stabilizing the pH value of a hydroponic vegetable working solution on the basis of a Japanese garden test nutrient solution formula, wherein each nutrient element in the nutrient solution formula comprises 17.33mmol/L of nitrogen, 8.0mmol/L of potassium, 1.33mmol/L of phosphorus, 4.0mmol/L of calcium, 2.0mmol/L of magnesium, 0.0897mmol/L of iron, 0.00792mmol/L of manganese, 0.00032mmol/L of copper, 0.04627mmol/L of boron, 0.000765mmol/L of zinc, 0.000208mmol/L of molybdenum, 2.0mmol/L of sulfur and 0-160mg/L (excluding 0) of citric acid or citrate.

In the case, the lettuce cultivation test is carried out in a plant factory under the full artificial light environment, 4 treatments are designed totally, 1 control, namely 5 gradient sodium citrate concentrations are 0mg/L (control) of CK, 40mg/L, N2 of N1, 80mg/L, N3 of N1, 160mg/L of N3556, and 6 repetitions of each treatment are set. Setting the initial nutrient solution EC to be about 2.0mS/cm, setting the initial pH to be 6.0, and in order to monitor the pH autonomous change condition of the nutrient solution from the post-planting to the pre-harvesting, not interfering the pH value of the nutrient solution after the planting, namely not adjusting the pH value, and supplementing the nutrient solution containing sodium citrate with corresponding concentration when the nutrient solution EC is reduced to be below 1.7 mS/cm. The daily pH monitoring is shown in FIG. 3, and the results of the experiments show that the pH fluctuations are larger for the control without addition of sodium citrate (CK, 0mg/L) and smaller for the treatment with addition of citric acid, wherein the pH of the working solution is maintained well within the desired range of 5.5-6.5 when the citric acid concentration is 40-120mg/L (N1-N3).

It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or terminal that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or terminal. Without further limitation, an element defined by the phrases "comprising … …" or "comprising … …" does not exclude the presence of additional elements in a process, method, article, or terminal that comprises the element. Further, herein, "greater than," "less than," "more than," and the like are understood to exclude the present numbers; the terms "above", "below", "within" and the like are to be understood as including the number.

Although the embodiments have been described, once the basic inventive concept is obtained, other variations and modifications of these embodiments can be made by those skilled in the art, so that the above embodiments are only examples of the present invention, and not intended to limit the scope of the present invention, and all equivalent structures or equivalent processes using the contents of the present specification and drawings, or any other related technical fields, which are directly or indirectly applied thereto, are included in the scope of the present invention.

Claims

1. A method for stabilizing the pH value of a plant water culture nutrient solution is characterized in that citric acid or citrate is added on the basis of the plant water culture nutrient solution, and the pH value of the nutrient solution is stabilized by utilizing the buffer property of the citric acid or citrate.

2. The method of claim 1, wherein the working solution of hydroponics is 40-120mg/L citric acid or citrate.

3. The method for stabilizing pH of plant hydroponics nutrient solution by adding citric acid or citrate as claimed in claim 2, wherein citric acid or citrate is added to nutrient solution dry powder, storage mother solution or cultivation working solution, so that the concentration of citric acid or citrate in the formulated cultivation working solution is 40-120 mg/L.

4. Use of the method of stabilizing the pH of a plant hydroponic nutrient solution of claim 1 or 2 or 3 in plant hydroponics.