CN106187451A - A kind of method preparing selenium-rich crops cultivation matrix with marc biomass carbon - Google Patents

Abstract

A method for preparing a selenium-enriched crop cultivation substrate with pomace biochar, characterized in that: the following steps are sequentially included: the first step, preparing pomace biochar; the second step, preparing selenium nutrient solution; the third step, Preparation of selenium-enriched biochar: (1) preparation of heated selenium-enriched biochar; (2) preparation of normal temperature selenium-enriched biochar; (3) mixing of heated selenium-enriched biochar with normal temperature selenium-enriched biochar Make selenium-enriched biochar; the fourth step, prepare modified starch binder; the fifth step, prepare selenium biochar granules; the sixth step, take selenium-enriched biochar and selenium biochar granules, and mix the two Sending it into a granulator for granulation; in the seventh step, stirring evenly the granules prepared in the sixth step with the crop soilless cultivation substrate filler to obtain a selenium-enriched crop cultivation substrate. The selenium-enriched cultivation substrate prepared by the method of the invention can improve the absorption and transformation rate of selenium element by crops, and the selenium element can be released slowly and uniformly in the whole growth cycle of crops.

Description

A method for preparing selenium-enriched crop cultivation substrate with pomace biochar

technical field

The invention relates to a soilless cultivation substrate and a preparation method thereof, in particular to a method for preparing a selenium-enriched crop cultivation substrate by using pomace biochar.

Background technique

Selenium is an essential trace element for the human body, and it is the active center of glutathione peroxidase (GSH-Px). Supplementing selenium in an appropriate amount can enhance the body's immunity, delay aging, and prevent and fight cancer. However, my country is a selenium-deficient country, and selenium-enriched agricultural products are an effective way for the human body to supplement selenium. Selenium in vegetables is divided into two categories: inorganic selenium and organic selenium. The former includes selenate, selenite, etc. Inorganic selenium is poorly absorbed by humans and animals, and has a high risk of toxicity. Improper use can easily cause selenium poisoning The latter mainly includes selenoamino acids, selenoproteins, selenium polysaccharides and other forms, which have good absorption effect and low toxicity for humans and animals, and are more suitable for the requirements of selenium supplementation. Therefore, applying selenium to crops to convert inorganic selenium into organic selenium and increasing the selenium content in humans or animals is a recognized safe and effective way to supplement selenium, which has important practical significance for the prevention and treatment of selenium deficiency in humans. At present, there are mainly the following ways to apply selenium to crops:

One is to plant crops with strong enrichment ability in natural selenium-rich areas. This method is difficult to quantitatively control selenium content, and there are geographical limitations, which is not conducive to large-scale standardized production, especially in most areas of my country that are selenium-deficient areas , do it unconditionally.

The second is to spray the inorganic selenium solution before the crops are harvested, so that the crops can quickly absorb the inorganic selenium to reach the selenium-enriched level. Such as Chinese patents CN1594234A, CN101182246A and so on. In this method, the implementation of the selenium-enriched nutrient is relatively complicated, and it needs to be sprayed 5 to 6 times, and the residual amount of inorganic selenium in the final crops is large. Before the absorption of inorganic selenium, it must be combined with the organic ligand in the intestinal tract before it can be absorbed by the body. However, there are a variety of elements in the intestinal tract that compete with selenium for limited ligands, which is not conducive to the absorption and utilization of the human body, and inorganic selenium has obvious toxic effects on the body.

The 3rd, topdressing selenium-enriched fertilizer, as Chinese patent CN101734971A. The method can ensure that the crops can reach the selenium-rich standard without inorganic selenium residues, and can increase the organic selenium content of vegetables. However, due to the fertilization of crops in large fields, the utilization rate of selenium fertilizer is low, and a large amount of selenium is easy to drip into the deep soil or rivers with irrigation water and rainwater, and the lost selenium is easy to increase the burden of selenium in the soil and water environment, and long-term use is easy to cause selenium. pollute.

According to relevant statistics, the input of chemical fertilizers accounts for about 50% of the total input of farmers in planting production, and 50% of the increase in grain production in developing countries comes from the role of chemical fertilizers. But at present, the utilization rate of nitrogen fertilizer in the current season in my country is only 20%-35%, the utilization rate of phosphorus fertilizer is 10%-20%, and the utilization rate of potassium fertilizer is 30%-60%, which is far lower than the utilization level of developed countries in the world. Selenium is a trace element, and the improvement of its utilization rate is also an urgent problem to be solved by agricultural science and technology workers in our country.

Biochar is a kind of highly aromatized refractory solid material formed by pyrolysis and carbonization of biomass at a low temperature of 300 ° C to 700 ° C. It has a high specific surface area, pore structure, certain mechanical strength and small accumulation. Density, which gives biochar a high adsorption performance. Biochar can increase soil carbon storage, improve soil, improve soil fertility, promote crop production and maintain the balance of soil ecosystem. Not only that, high stability, economy, carbon sequestration and emission reduction, and the specific adsorption and retention characteristics of N, P and other nutrients make it an ideal fertilizer adsorbent. On the other hand, my country is rich in crop straw biomass resources, but it is mainly treated and disposed of by open-air simple incineration, which leads to extremely serious waste of resources and environmental pollution. If the cheap and easy-to-get crop straw biomass raw material can be properly processed into an adsorbent suitable for selenium, and then selenium-containing biochar can be incorporated into the substrate material to prepare an environmentally friendly selenium-rich vegetable cultivation substrate, not only can Effectively solve the problem of crop straw disposal, make efficient use of crop straw waste resources, and can promote the efficient transformation and enrichment of selenium in vegetables.

The journal paper "Effects of Selenium Fertilizer on Potato Selenium Absorption, Transformation, Yield and Quality" (Yin Jinyan, Geng Zengchao, Li Zhiying et al. 2015, 35(3): 823-829) reported a biochar-based selenium fertilizer and its application effect, When the appropriate amount of selenium (0.379kg/hm ² ) was applied, the potato yield increased by 4.87%-5.44%, the crude protein content increased by 12.18%-20.03%, the reducing sugar increased by 6.45%-12.90%, and the vitamin C content increased- 0.54%~3.1l%, the conversion rate of organic selenium increased by 13.00%~15.10%, and the starch content increased by -0.73%~1.12%. Biochar-based selenium fertilizer is prepared by adsorption reaction of sodium selenate and biochar in the laboratory. The ratio of biochar to selenium is 176:1. Among them, biochar is produced by batch pyrolysis pilot equipment and passed through a 1mm sieve. The selenium source is analytically pure Na ₂ Se0 ₄ ·10H ₂ 0. The biochar-based selenium fertilizer reported in this article is essentially a fertilizer applied to the soil. It can only be used after scientific experiments to determine the application amount and application technology applied to various vegetable crops. Difficulty of application.

The Chinese patent "A group of far-infrared functional selenium-rich chromium-rich microbial fertilizers and its preparation method" (publication number 104692903A) provides a cultivation substrate (i.e. leftovers) and biochar of artificially cultivated selenium-rich chromium-rich Cordyceps militaris (Charcoal fired from waste such as bamboo charcoal, charcoal, and orange stalks) is a microbial fertilizer that is compatible with the main raw materials.

Chinese patent CN104177194A discloses a method for preparing a carbon-based selenium fertilizer. The cultured microorganisms are filtered from the culture medium to attach the microorganisms to the surface of the biochar, and then the nutrient solution rich in selenium is immersed in the biochar to make the Crop probiotics and biochar can fully contact and absorb selenium in nutrient solution and other elements needed by crops, and in situ reduce selenium to elemental selenium, and finally produce carbon-based selenium fertilizer rich in selenium.

Above-mentioned 3 examples all adopt active ingredient selenium to make a kind of selenium fertilizer for soil application. However, the biggest problem with selenium fertilizer is that it is difficult to master the application technology. It is usually necessary to propose the application amount, application method, etc. after conducting special experiments on various crops, and then recommend them to users. Secondly, even if farmers have mastered the application technology, due to fertilization of vegetables in large fields, the utilization rate of selenium fertilizer is low, and a large amount of selenium is easy to drip into the deep soil or rivers with irrigation water and rainwater, and the lost selenium is easy to increase the amount of selenium in the soil and water environment. The burden of long-term use can easily lead to selenium pollution. Thirdly, due to the different depths of the cultivated layers, it is difficult to apply selenium fertilizer accurately and quantitatively, and it is easy to cause waste of fertilizer.

Chinese patent CN104585001A discloses a soilless cultivation method for increasing the organic selenium content of eggplant. The operation steps of the method are firstly preparing a soilless cultivation substrate containing nano-selenium, and then selecting robust eggplant seedlings, disinfecting the roots of the eggplant seedlings and transplanting them to The custom-made tanks in the greenhouse are filled with soilless cultivation substrates containing nano-selenium, and the eggplants are managed by conventional methods such as pruning, disease control, flower promotion and fruit preservation, and the fruits are picked after ripening to obtain eggplants with high organic selenium content.

Chinese patent CN104591866A discloses a soilless cultivation substrate containing nano-selenium and a preparation method thereof. The disclosed content of the invention is that a soilless cultivation substrate containing nano-selenium includes raw materials such as animal urine, crop straw, industrial and agricultural by-products, selenium dioxide, and machine-made sand. The fermented material and selenium dioxide are mixed to obtain decomposed organic matter containing nano-selenium, and the decomposed organic matter is mixed with machine-made sand to make a soilless culture substrate containing nano-selenium.

The commonality of the above technologies is that the nano-selenium plant nutrient is combined with other matrix materials, and the effect is average.

The journal paper "Effect of Substrate Selenium Application on Selenium Enrichment Effect and Quality of Lettuce" (Shanxi Agricultural Sciences 2013, 41(1):57-59) reported a method of adding selenium to vegetable cultivation substrate. The tested selenium is analytically pure sodium selenite (Na ₂ SeO ₃ ) reagent. First, peat and perlite are prepared into a mixed matrix at a volume ratio of 2:1. There are 5 gradients of sodium selenite treatment, the amount of selenium applied to the substrate is 0, 0.3, 0.6, 1.2, 2.5 mg/kg respectively, after sodium selenite is formulated into a solution, it is sprayed into the substrate with a small sprayer, and Mix well with base. The matrix prepared by this technology has a relatively simple process, and the matrix has limited slow-release ability of selenium. Selenium is easy to be released quickly in a short period of time, which is not coordinated with the absorption mechanism of crops. Therefore, the effect is general and the conversion rate of selenium is low.

Therefore, how to provide a method for preparing a selenium-enriched vegetable cultivation substrate with high absorption rate and high conversion rate and slow release of selenium element throughout the whole growth cycle of crops by using crop straw biochar has become the research topic of the present invention.

Contents of the invention

The invention provides a method for preparing a selenium-enriched crop cultivation substrate by using pomace biomass charcoal, and aims to solve the problem that the existing vegetable cultivation substrate has a low absorption conversion rate of selenium element.

In order to achieve the above object, the technical solution adopted in the present invention is: a method for preparing selenium-enriched crop cultivation substrate with pomace biochar, said method comprising the following steps in turn:

The first step is to prepare pomace biochar,

After drying the pomace, put it into the pyrolysis furnace, pass in argon gas to get rid of the oxygen in the pyrolysis furnace, quickly raise the temperature in the pyrolysis furnace to 95°C~105°C within 5 minutes, and then Heating at a heating rate of 1°C/min to 550°C~600°C, and keeping it for 25~35 minutes, after natural cooling to room temperature, collect the biomass, crush it, and pass it through a 60-mesh sieve to obtain pomace biochar;

The second step is to prepare selenium nutrient solution,

Dissolve Na ₂ Se0 ₄ ·10H ₂ O or Na ₂ SeO ₃ and water at a weight ratio of 1:20~1:40 to make a selenium salt solution, and then add an acid agent to the selenium salt solution to adjust the pH of the selenium salt solution to 4.5 ~5.5, the selenium nutrient solution was prepared;

The third step is to prepare selenium-enriched biochar:

(1) Heating a part of the pomace biochar prepared in the first step to 70°C to 100°C, immediately spraying the selenium nutrient solution evenly on the pomace biochar, the selenium nutrient solution and the pomace biochar The volume of material charcoal is 1:15~1:30, while spraying and stirring, the heated selenium-enriched biochar is obtained;

(2) Take the pomace biochar prepared in the first step described in the other part, and evenly spray the selenium nutrient solution on the pomace biochar at 10°C~40°C, the selenium nutrient solution and the pomace biomass The volume of charcoal is 1:15~1:30, and it is stirred while spraying to obtain selenium-enriched biochar at normal temperature;

(3) Mixing the heated selenium-enriched biochar and the normal temperature selenium-enriched biochar to make selenium-enriched biochar, wherein the volume ratio of the heated selenium-enriched biochar to the normal temperature selenium-enriched biochar is 7:3~6:4;

The fourth step is to prepare modified starch binder,

First, 50 parts by weight of corn or tapioca starch are dissolved in 90 to 100 parts by weight of water, 2 to 3 parts by weight of concentrated sulfuric acid are added under constant stirring for catalysis, and then 5 parts by weight of potassium permanganate solution is added to oxidize for 1 to 1.5 hours and Stir continuously, then add 4 parts by weight of sodium hydroxide for gelatinization for 20-30 minutes, add 1 part by weight of borax for cross-linking for 15-20 minutes, and finally add water to fully stir and cool to obtain a starch viscose with a mass concentration of 0.2-0.5%. Binder;

The fifth step is to prepare selenium biochar granules,

The selenium-enriched biochar prepared in the third step is sent into a mixer with a nozzle above, and the starch binder with a mass concentration of 0.2 to 0.5% is evenly sprayed while stirring the material, and the selenium-enriched biochar is bonded to the starch. The volume ratio of the binder is 95-90:5-10 to prepare selenium biochar granules;

The sixth step is to take the selenium-enriched biochar prepared in the third step and the selenium biochar granules prepared in the fifth step, and mix the two evenly to obtain a wet material, selenium-enriched biochar and selenium biochar granules The volume ratio of the agent is 2~4:8~6, and then the wet material is sent to a granulator with a hot air blower for granulation, the set speed is 250~300r/min, and the temperature is 70~120°C. After granulation for 30~40 minutes, pass through a 30-mesh sieve;

In the seventh step, the granules prepared in the sixth step and the crop soilless cultivation substrate filler are evenly stirred at a weight ratio of 1:100 to 1:200 to obtain the selenium-enriched crop cultivation substrate.

The relevant content in the above-mentioned technical scheme is explained as follows:

1. In the above scheme, the pomace is selected from at least one of apple pomace, pear pomace, peach pomace, strawberry pomace, kiwi pomace, grape pomace, watermelon pomace, banana pomace and pineapple pomace; Before, the pomace is air-dried until the water content is less than 40%, and crushed until the average diameter of the particles is not greater than 10 cm.

2. In the above scheme, the acid agent added in the second step is acetic acid or dilute hydrochloric acid.

3. In the above scheme, "parts by weight" in the fourth step refers to a content unit expressed by taking any weight as 1 part.

4. In the above solution, the raw material of the crop soilless culture matrix filler is a mixture of at least two of peat, perlite, coconut shell, sandstone, vermiculite, sawdust, slag and corn stalk. The selection of soilless culture matrix filler is an existing technology, which can be purchased or self-made, and can also be made from other wastes, and is suitable for plant growth. The formula of soilless culture matrix filler is as follows:

(1) 7 parts peat, 3 parts perlite; (2) 1 part coconut shell, 1 part sand; (3) 1 part peat, 1 part vermiculite, 1 part sawdust; (4) 1 part peat, 1 part Sawdust; (5) 1 part peat, 1 part perlite, 1 part sand; (6) 2 parts peat, 2 parts vermiculite, 5 parts slag, 1 part perlite; (7) 1 part peat, 1 part slag ; (8) 1 part of peat, 1 part of bark; (9) 3 parts of corn stalk, 2 parts of slag; (10) 1 part of corn stalk, 1 part of peat, 3 parts of slag.

The design principle of the present invention is: the present invention proposes a crop soilless culture substrate rich in selenium element, which is characterized in that the selenium element slow-release technology is used to make the cultivated crops have a higher absorption and utilization rate of selenium element throughout the growth cycle , and the user does not need to apply selenium fertilizers, but only needs to apply a large number of elements such as nitrogen, phosphorus, potassium or cultivation nutrient solution according to routine management, so it is easier to master the application method, and the selenium content of vegetables is controlled within a safe range to produce safe, high-quality vegetables. , clean green selenium-rich vegetables, and will not cause pollution to the environment.

In the second step of the method of the present invention, the purpose of adjusting the selenium nutrient solution to acidity is that the pH of the crop straw biochar is about 8-10, and after the subsequent spraying of the selenium nutrient solution on the crop straw biochar, It is beneficial to adjust the pH of crop straw biochar from 8 to 10 to a neutral value of about 7.0, which is beneficial to plant growth.

In the third step, the heated selenium-enriched biochar and the normal-temperature selenium-enriched biochar are prepared respectively, with the purpose of increasing the porosity of the biochar under the heating condition of 70°C to 100°C, and more selenium is absorbed. Retained in the micropores of the biochar, the release time of selenium in the cultivation medium of the heated selenium-enriched biochar prepared under heating conditions is longer than that of the selenium-enriched biochar at normal temperature. Therefore, Mixing the heated selenium-enriched biochar with the normal-temperature selenium-enriched biochar can ensure that the selenium release period is extended and the selenium is evenly released in different growth periods of the crops.

In the sixth step, since the selenium-enriched biochar in the third step is not bonded by a starch binder, and the selenium biochar granules in the fifth step are wrapped by a starch binder, the two are separated in the absence of a starch binder. The release rate of selenium in the soil cultivation substrate is different. The selenium release rate of the selenium biochar granule in the fifth step is slower, and the selenium release rate of the selenium-enriched biochar in the third step is relatively fast. Mix the two evenly to make The grains can effectively control the release rate of selenium in the soilless culture substrate, ensuring that the selenium can be released evenly in different growth periods of the crops for absorption and utilization of the crops, and ensure the extension of the selenium release period;

Due to the use of the above-mentioned technical solutions, the present invention has the following advantages and effects compared with the prior art:

1. The present invention comprehensively uses the adsorption principle of biochar and the bonding performance of the modified starch binder to improve the absorption and slow release ability of selenium element, which can ensure that the selenium element can be maintained within a long vegetable growth cycle of 3 to 7 months. Selenium supply, thus ensuring a high conversion rate of selenium in crops, because the characteristics of biochar, such as porosity, huge specific surface area, surface negative charge and charge density, can absorb and hold nutrients in fertilizers , to achieve its slow-release effect, significantly reduce the loss of selenium, improve soil fertility, promote crop production and maintain the balance of the soil ecosystem.

2. The effective carrier of selenium used in the present invention is Na ₂ SeO ₄ •10H ₂ O or sodium selenite (Na ₂ SeO ₃ ), Na ₂ SeO ₄ •10H ₂ O or sodium selenite (Na ₂ SeO ₃ ) It is an effective carrier that is more easily absorbed by crops and more environmentally friendly.

3. The substrate prepared by this method can be precisely customized according to the lifetime selenium demand of different vegetable crops. The cultivation substrate provided by the present invention does not need to add selenium again manually, and can be directly put into the cultivation container to plant various vegetables, and After planting, it only needs to be managed according to the routine, and a large number of elements such as nitrogen, phosphorus, and potassium or cultivation nutrient solution are applied, so it is easier to master the application method, and the selenium content of vegetables is controlled within a safe range to produce safe, high-quality, clean green rich Selenium vegetables, and will not cause pollution to the environment.

4. The crop cultivation substrate prepared by this method is a directly applicable crop cultivation carrier, and the journal article "Selenium Fertilizer Effects on Potato Selenium Absorption, Transformation, Yield, and Quality" (Yin Jinyan, Geng Zengchao, Li Zhiying, etc. 2015, 35( 3): 823-829) reported a biochar-based selenium fertilizer, which is a kind of trace element fertilizer. It can only be used after scientific experiments are carried out to determine the application amount and application technology for various vegetable crops. Increase application difficulty.

5. The selenium element in the selenium-enriched matrix of the present invention is not easy to lose, and the utilization rate is obviously improved, which is more suitable for facility cultivation.

6. After applying the method of the present invention, when the selenium content in the cultivation medium is 2-10 mg/kg, the organic selenium content in the harvested tomato is 5-200 μg/kg, and the organic selenium accounts for ≥85% of the total selenium.

In a word, the selenium-enriched crop cultivation substrate prepared by the method of the present invention can improve the absorption and conversion rate of selenium element by crops, and the selenium element in the selenium-enriched crop cultivation substrate can be released slowly and evenly during the whole growth cycle of vegetable crops, The vegetable crops can effectively absorb the selenium element in each growth period, therefore, the organic selenium content in the cultivated vegetable crops is relatively high, which greatly improves the added value of the commodity.

Description of drawings

Accompanying drawing 1 is the technical road map of the inventive method;

Accompanying drawing 2 is the dynamic variation diagram of selenium element dissolution rate in the selenium-enriched cucumber cultivation substrate of embodiment one and common soilless cultivation substrate;

Accompanying drawing 3 is the comparison diagram of the content of organic selenium in the cucumber after the cucumber is harvested between the selenium-enriched cucumber cultivation substrate of Example 1 and the common soilless cultivation substrate.

detailed description

The present invention will be further described below in conjunction with embodiment:

Embodiment 1: A kind of method of preparing selenium-enriched crop cultivation substrate with pomace biochar

The method comprises the following steps in turn:

The first step is to prepare pomace biochar,

Put the fruit pomace into the pyrolysis furnace after drying, pass in argon gas to get rid of the oxygen in the pyrolysis furnace, rapidly raise the temperature in the pyrolysis furnace to 100°C within 5 minutes, and then increase the temperature at 1°C/ Heating at a heating rate of 1 minute to 550°C and maintaining it for 30 minutes, after naturally cooling to room temperature, collecting the biomass, pulverizing, and passing through a 60-mesh sieve to obtain pomace biochar; the pomace is selected from apple pomace, pear pomace at least one of pomace, peach pomace, strawberry pomace, kiwi fruit pomace, grape pomace, watermelon pomace, banana pomace and pineapple pomace; before being put into the pyrolysis furnace, the pomace is air-dried until the water content is less than 40%, and crushed The average diameter of the particles is not more than 10cm;

The second step is to prepare selenium nutrient solution,

Dissolving Na ₂ Se0 ₄ ·10H ₂ O or Na ₂ SeO ₃ with water at a weight ratio of 1:20 to make a selenium salt solution, and then adding acetic acid to the selenium salt solution to adjust the pH of the selenium salt solution to 4.5~5.5 to obtain Selenium nutrient solution;

The third step is to prepare selenium-enriched biochar:

(1) Heating a part of the pomace biochar prepared in the first step to 70°C, and immediately spraying the selenium nutrient solution evenly on the pomace biochar, the difference between the selenium nutrient solution and the pomace biochar The volume is 1:20, while spraying and stirring, the heated selenium-enriched biochar is obtained;

(2) Take the pomace biochar prepared in the first step described in the other part, and evenly spray the selenium nutrient solution on the pomace biochar at room temperature (that is, at room temperature, about 10°C~40°C). Above, the volume of selenium nutrient solution and pomace biochar is 1:20, and they are sprayed and stirred to prepare selenium-enriched biochar at normal temperature;

(3) Mixing the heated selenium-enriched biochar and the normal temperature selenium-enriched biochar to make selenium-enriched biochar, wherein the volume ratio of the heated selenium-enriched biochar to the normal temperature selenium-enriched biochar is 7:3;

The fourth step is to prepare modified starch binder,

First, 50 parts by weight of corn or tapioca starch are dissolved in 100 parts by weight of water, 2 parts by weight of concentrated sulfuric acid is added under constant stirring for catalysis, then 5 parts by weight of potassium permanganate solution is added to oxidize for 1 hour and continuously stirred, then 4 parts by weight of potassium permanganate are added. The sodium hydroxide gelatinization of weight part is 20 minutes, add 1 weight part of borax cross-linking 15 minutes, add the starch binder that the mass concentration is 0.3% after adding water fully to stir finally;

The fifth step, preparing selenium biochar granules

The selenium-enriched biochar prepared in the third step is sent into the mixer with a nozzle above, and the starch binder with a mass concentration of 0.3% is uniformly sprayed while stirring the material, and the selenium-enriched biochar and the starch binder The volume ratio is 90:10 to prepare selenium biochar granules;

The sixth step is to take the selenium-enriched biochar prepared in the third step and the selenium biochar granules prepared in the fifth step, and mix the two evenly to obtain a wet material, selenium-enriched biochar and selenium biochar granules The volume ratio of the agent is 3:7, and then the wet material is sent into a drum granulator with a hot air blower, the set speed is 300r/min, the temperature is 70°C, after 30-40 minutes of granulation, after 30 Mesh sieve;

The seventh step is to mix the granules prepared in the sixth step with the vegetable soilless culture matrix filler in a weight ratio of 1:100, wherein the soilless culture matrix filler is made of peat and perlite in a volume ratio of 3: 1 prepared by uniform mixing, and finally, the selenium-enriched vegetable cultivation substrate is prepared.

In the eighth step, put the selenium-enriched vegetable cultivation substrate into an 8L cultivation bag, and add the same amount of Na ₂ Se0 ₄ ·10H to the common soilless cultivation substrate (peat and perlite in a volume ratio of 3:1) The matrix of ₂ O was used as a control, and the content of selenium in the two kinds of matrix was the same, and the content of selenium was 5.2mg/kg. Plant one cucumber per bag, and regularly water with conventional NPK nutrient solution (Hoagland nutrient solution) and water. Determination after harvesting the cucumber at the mature stage shows that, referring to the accompanying drawings 2 and 3, the organic selenium content of the biochar selenium-enriched matrix treatment is 5.9 μ g/kg, and the organic selenium accounts for 86.4% of the total selenium content, while sodium selenate (Na ₂ Se0 ₄ ·10H ₂ O) was directly added to the commercial matrix (control) with a content of 3.3 μg/kg, and organic selenium accounted for 65.1% of the total selenium. It shows that the slow-release effect of selenium in biochar selenium-enriched matrix is obvious, and it has been fully absorbed and utilized by crops.

Embodiment 2: A kind of method of preparing selenium-enriched strawberry cultivation substrate with pomace biochar

The method comprises the following steps in turn:

The first step is to prepare pomace biochar,

Put the fruit pomace into the pyrolysis furnace after drying, feed argon gas to get rid of the oxygen in the pyrolysis furnace, rapidly raise the temperature in the pyrolysis furnace to 105°C within 5 minutes, and then increase the temperature at 1°C/ Heat up to 600°C at a heating rate of 1 minute, and keep it for 25 minutes. After naturally cooling to room temperature, collect the biomass, pulverize it, and pass it through a 60-mesh sieve to obtain pomace biochar;

The second step is to prepare selenium nutrient solution,

Dissolve analytically pure Na ₂ SeO ₃ and water at a weight ratio of 1:30 to make a selenium salt solution, and then add dilute hydrochloric acid to the selenium salt solution to adjust the pH of the selenium salt solution to 4.5-5.5 to obtain a selenium nutrient solution;

The third step is to prepare selenium-enriched biochar:

(1) Heating a part of the pomace biochar prepared in the first step to 100°C, and immediately spraying the selenium nutrient solution evenly on the pomace biochar, the difference between the selenium nutrient solution and the pomace biochar The volume is 1:30, while spraying and stirring, the heated selenium-enriched biochar is obtained;

(2) Take the pomace biochar prepared in the first step described in the other part, and evenly spray the selenium nutrient solution on the pomace biochar at room temperature (about 10°C~40°C), the selenium nutrient solution and The volume of pomace biochar is 1:20, and it is stirred while spraying to prepare selenium-enriched biochar at normal temperature;

(3) Mixing the heated selenium-enriched biochar and the normal temperature selenium-enriched biochar to make selenium-enriched biochar, wherein the volume ratio of the heated selenium-enriched biochar to the normal temperature selenium-enriched biochar is 6:4;

The fourth step is to prepare modified starch binder,

First, 50 parts by weight of corn or tapioca starch are dissolved in 100 parts by weight of water, 3 parts by weight of concentrated sulfuric acid is added under constant stirring for catalysis, then 5 parts by weight of potassium permanganate solution is added to oxidize for 1.5 hours and continuously stirred, and then 4 parts by weight of potassium permanganate are added. The sodium hydroxide gelatinization of weight part is 20 minutes, add 1 weight part borax cross-linking 15 minutes, add water and fully stir at last and cool down to obtain the starch binder that mass concentration is 0.2%;

The fifth step, preparing selenium biochar granules

The selenium-enriched biochar prepared in the third step is sent into the mixer with a nozzle above, and the starch binder with a mass concentration of 0.2% is evenly sprayed while stirring the material, and the selenium-enriched biochar and the starch binder The volume ratio is 95:5 to prepare selenium biochar granules;

The sixth step is to take the selenium-enriched biochar prepared in the third step and the selenium biochar granules prepared in the fifth step, and mix the two evenly to obtain a wet material, selenium-enriched biochar and selenium biochar granules The volume ratio of the agent is 2:8, and then the wet material is sent into a drum granulator with a hot air blower, the set speed is 250r/min, the temperature is 70°C, and after 40 minutes of granulation, pass through a 30-mesh sieve ;

In the seventh step, the granules prepared in the sixth step and the soilless vegetable cultivation substrate filling material are evenly stirred at a weight ratio of 1:150 to obtain the selenium-enriched vegetable cultivation substrate.

Wherein, the preparation of soilless culture substrate filler:

(1) Use a feed grinder or a straw rubbing machine to crush the rice straw into 5-10cm long;

(2) Edible fungus residue is the discarded culture substrate after the production of edible fungi, such as Coprinus comatus and Flammulina velutipes residue, crushed to 2~5mm;

(3) The cassava residue is the fermentation waste after making wine in the alcohol factory, with a diameter of 1~3mm;

Mix the above-mentioned rice straw, edible fungus residue, and cassava residue in a volume ratio of 4:1:5 to obtain a mixture;

The above mixture is stacked into strips for aerobic compost fermentation. The stacks are 1-3 meters high, 2-8 meters wide, and 30-100 meters long; the water content of the stacks is controlled at 50%-65%. Ventilation and oxygen supply during production; control the temperature of the pile in the range of 65°C to 45°C, turn over the pile in time when the temperature exceeds this range, and complete the fermentation of the pile when the temperature of the mixture is equal to the ambient temperature (generally about 30 days). The obtained decomposed matter is air-dried until the water content is 30-40%, which is the matrix filler.

In the eighth step, put the selenium-enriched cultivation substrate into an 8L cultivation bag, and set a substrate in which the same amount of sodium selenite (Na ₂ SeO ₃ ) was applied to the ordinary soilless cultivation substrate filler as a control, and the two substrates The selenium content is the same, and the selenium content is 6.1mg/kg. Plant one strawberry in each bag, and regularly irrigate the conventional NPK nutrient solution (Hoagland nutrient solution) and water. After harvesting the strawberries at the mature stage, the measurement shows that the organic selenium content of the biochar selenium-enriched substrate is 4.1 μg/kg, organic Selenium accounted for 67.3% of the total selenium content, while the content of sodium selenite (Na ₂ SeO ₃ ) directly added to the matrix filler (control) was 1.8 μg/kg, and organic selenium accounted for 45.2% of the total selenium content. It shows that the slow-release effect of selenium in biochar selenium-enriched matrix is obvious, and it has been fully absorbed and utilized by crops.

The above-mentioned embodiments are only to illustrate the technical concept and characteristics of the present invention, and its purpose is to allow those familiar with this technology to understand the content of the present invention and implement it accordingly, and cannot limit the protection scope of the present invention with this. The selenium-enriched crop cultivation substrate prepared by the method can be used to grow various crops, including vegetables and fruits, such as cabbage, eggplant, tomato, lettuce, konjac, Chinese cabbage, broccoli, asparagus, lettuce, radish, spinach, green pepper, etc. . All equivalent changes or modifications made according to the spirit of the present invention shall fall within the protection scope of the present invention.

Claims (4)

1. the method preparing selenium-rich crops cultivation matrix with marc biomass carbon, it is characterised in that: described method is wrapped successively Include the following step:

The first step, prepares marc biomass carbon,

Marc is added in pyrolysis oven after drying, is passed through argon, to get rid of the oxygen in pyrolysis oven, pyrolysis in-furnace temperature is existed It is rapidly heated within 5 minutes to 95 DEG C ~ 105 DEG C, is heated to 550 DEG C ~ 600 DEG C with the heating rate of 1 DEG C/min the most again, and Keep 25 ~ 35 minutes, after naturally cooling to room temperature, biomass collection, pulverize, cross 60 mesh sieve, prepare marc biomass carbon；

Second step, prepares selenium nutrient solution,

By Na₂Se0₄·10H₂O or Na₂SeO₃Selenium salt solution is made by weight 1:20 ~ 1:40 dissolving with water, then to selenium salt solution Add the acid agent pH to 4.5 ~ 5.5 with regulation selenium salt solution, prepare selenium nutrient solution；

3rd step, prepares Se-enriched bio charcoal:

(1) the marc biomass carbon that a part of described first step prepares is heated to 70 DEG C ~ 100 DEG C, immediately by described selemium nutrition Liquid is uniformly sprayed on marc biomass carbon, and selenium nutrient solution is 1:15 ~ 1:30 with the volume of marc biomass carbon, and sprinkling limit, limit is stirred Mix, prepare state Se-enriched bio charcoal of heating；

(2) take the marc biomass carbon that the first step described in another part prepares, at 10 DEG C ~ 40 DEG C, selenium nutrient solution is uniformly sprayed On this marc biomass carbon, selenium nutrient solution is 1:15 ~ 1:30 with the volume of marc biomass carbon, and sprinkling limit, limit is stirred, and prepares Normal-temperature Se-enriched bio charcoal；

(3) described state Se-enriched bio charcoal of heating is mixed and made into Se-enriched bio charcoal with described normal-temperature Se-enriched bio charcoal, wherein, adds Temperature state Se-enriched bio charcoal is 7:3 ~ 6:4 with the volume ratio of normal-temperature Se-enriched bio charcoal；

4th step, prepares Modified-Starch Binder,

First Semen Maydis or the tapioca of 50 weight portions are dissolved in the water of 90 ~ 100 weight portions, are stirred continuously lower addition 2 ~ 3 The sulphuric acid catalysis of weight portion, is subsequently adding 5 weight portion potassium permanganate solution oxides 1 ~ 1.5 hour and is stirred continuously, adding 4 The sodium hydroxide gelatinizing of weight portion 20 ~ 30 minutes, adds 1 weight portion Borax and cross-links 15 ~ 20 minutes, finally add and fully stir into water After mixing, cooling obtains the starch adesive that mass concentration is 0.2 ~ 0.5%；

5th step, prepares selenium charcoal granule,

The Se-enriched bio charcoal described 3rd step prepared has in the blender of shower nozzle above sending into, while stirring material uniformly Spraying mass concentration is the starch adesive of 0.2 ~ 0.5%, and described Se-enriched bio charcoal is 95 ~ 90 with the volume ratio of starch adesive: 5 ~ 10, prepare selenium charcoal granule；

6th step, takes the selenium charcoal granule that the prepared Se-enriched bio charcoal of described 3rd step prepares with described 5th step, by two Person's mix homogeneously obtains wet stock, and Se-enriched bio charcoal is 2 ~ 4:8 ~ 6 with the volume ratio of selenium charcoal granule, then by described wet stock Sending into and have pelletize in the comminutor of hot-air blower, setting speed is 250 ~ 300r/min, and temperature is 70 ~ 120 DEG C, pelletize 30 ~ 40 After minute, cross 30 mesh sieves；

7th step, the granule described 6th step prepared and crop soilless culture substrate inserts are by weight 1:100 ~ 1:200 Stir, i.e. prepare described selenium-rich crops cultivation matrix.

A kind of method preparing selenium-rich crops cultivation matrix with marc biomass carbon the most according to claim 1, its feature It is: described marc is selected from pomace, pears slag, Fructus Persicae slag, Fructus Fragariae Ananssae slag, Fructus actinidiae chinensis slag, treaster, Citrullus vulgaris slag, Fructus Musae slag and spinach At least one in trailing plants slag；Put into before pyrolysis oven, by described marc dry in the sun to water content less than 40%, be crushed to granule Average diameter be not more than 10cm.

A kind of method preparing selenium-rich crops cultivation matrix with marc biomass carbon the most according to claim 1, its feature It is: the sour agent added in described second step is acetic acid or dilute hydrochloric acid.

A kind of method preparing selenium-rich crops cultivation matrix with marc biomass carbon the most according to claim 1, its feature It is: the raw material of described crop soilless culture substrate inserts is the peat composed of rotten mosses, perlite, Exocarpium cocois (Cocos nucifera L), sandstone, Vermiculitum, wood sawdust, stove The mixture of at least two in slag and corn straw.