Method for improving lunar soil, improved lunar soil and method for planting crops on lunar soil

Abstract

The invention discloses a lunar soil improvement method, improved lunar soil and a lunar soil crop planting method, and relates to the technical field of lunar soil utilization. The lunar soil improvement method comprises the following steps: uniformly mixing diluted urine and simulated lunar soil according to a liquid-solid ratio of 1ml: (2-20) g to obtain a mixture, adding 103-105 diatom strains into each 1ml of the mixture, and continuously culturing under the condition of carbon dioxide to obtain the improved lunar soil. According to the lunar soil improvement method provided by the invention, waste regeneration can be realized, diatom can be rapidly propagated, oxygen can be provided, the concentration of carbon dioxide can be reduced, and the lunar soil can become an effective plant cultivation medium, so that large-scale lunar soil improvement and crop cultivation are realized; therefore, nutrition supply required by long-term stationing and stable operation of bases such as lunar soil and the like is realized. The method has the advantages of high efficiency, easiness in implementation, low cost, easiness in large-scale and large-range application and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of in-situ utilization of lunar soil, and in particular to a method for improving lunar soil, a method for improving lunar soil and a method for planting crops using lunar soil. Background Art

[0002] Lunar soil (abbreviated as lunar soil) refers to the unique soil on the moon. It is the result of space weathering. The mineral powder that makes up the lunar soil is basically formed by the impact and crushing of meteorites.

[0003] The chemical composition, rock type and mineral composition of lunar soil are complex, and each lunar soil sample is composed of a variety of rocks and minerals. The soil is rich in helium-3, which is considered an efficient, clean, safe and cheap fuel for controlled nuclear fusion power generation because it does not produce neutrons during the fusion process and has low radioactivity. Lunar soil does not contain any organic nutrients and is very dry, so plants cannot be grown. However, lunar soil is helpful for studying matter and energy in the solar system, and can help humans better understand the history of the moon and the evolution of the Earth-Moon system. In addition, human understanding and research of lunar soil is an indispensable foundation for lunar exploration, as well as the establishment of a lunar base and the use of the moon in the future.

[0004] my country plans to land on the moon and then build a basic lunar base. The establishment of a lunar base requires the supply of food and vegetables for the safety of aviation personnel. However, the corresponding transportation from the earth is extremely costly and unsustainable. Therefore, the cultivation of crops is the key to the establishment and long-term stable operation of bases such as the moon. However, using local materials and directly using lunar soil cannot achieve crop growth and harvesting. This is because the porosity of lunar soil minerals is low and nutrients are difficult to supply; the lunar soil mineral particles are sharp, which affects the development of crops; the lunar soil minerals have a high content of heavy metals, which are poisonous to crop growth; and there is no microorganism or organic matter, so it is difficult to supply nutrients to crops. Lunar soil improvement is a necessary way to plant crops and needs to be carried out urgently.

[0005] Existing research is to add organic components to the lunar soil, and perform aerobic fermentation at a certain temperature while adding a large amount of water, so as to produce organic nutrients that can be used by plants and make wheat seedlings germinate. However, this improvement has the following problems: 1) This can only improve the problem of lack of organic nutrients in the lunar soil, but cannot improve the problem of sharp minerals that damage the root system; 2) A large amount of fresh water must be added in this process, and it is well known that the most scarce resource on the moon is water. This demand is not only difficult to meet, but may also cause waste; 3) Aerobic fermentation is required, and oxygen is also an important life-essential raw material for space stations and lunar bases. While ensuring the use of personnel, it is difficult to reuse it for other purposes, so it is difficult to support lunar soil improvement; 4) The high content of heavy metals and the inability to supply inorganic nutrients cause the produced fruits, vegetables, grains, etc. to be harmful; the crops and fruits and vegetables grown under the background of high heavy metals contain heavy metals that will cause poisoning to the personnel of the base; 5) A certain temperature is required for fermentation, which leads to the loss of energy in the base. In summary, the above improvement scheme is difficult to carry out and use on a large scale.

[0006] In view of this, the present invention is proposed. Summary of the invention

[0007] The purpose of the present invention is to provide a method for improving lunar soil, a method for improving lunar soil and a method for planting crops using lunar soil.

[0008] The present invention is achieved in that:

[0009] In a first aspect, the present invention provides a method for improving lunar soil, comprising: mixing diluted urine and simulated lunar soil at a liquid-solid ratio of 1 ml: 2-10 g to obtain a mixture, and adding 10 3 ~10 5 Diatom strains were added in a ratio of 1 diatom strain to 2 diatom strains, and continuous culture was carried out under carbon dioxide conditions to obtain improved lunar soil.

[0010] In an optional embodiment, the diatom strain is marine algae and / or brackish water diatom that has been acclimated to tolerance.

[0011] In an optional embodiment, the tolerance domestication method comprises mixing urine diluted 5 to 10 times with a diatom culture solution in a first volume ratio, culturing diatoms, and obtaining corresponding algae species after continuous culturing for 5 to 10 generations; then placing the algae species in urine diluted 5 to 10 times and mixing it with a diatom culture solution in a second volume ratio, culturing for 5 to 10 generations to obtain corresponding algae species, repeating the above process, wherein the volume of urine in the first volume ratio is smaller than the volume of the diatom culture solution, and the volume ratio of the concentration of urine diluted 5 to 10 times to the diatom culture solution is gradually increased until the diatom culture solution is not used for culturing, and the diatoms that can still grow normally are the domesticated diatoms;

[0012] Preferably, the changing trend of the volume ratio gradually changes from 1:9-11, 1:4-6, 1:2-3, 1:1, 1.5-2.5:1, 4-6:1, 9-11:1 and diatom-free culture solution.

[0013] In an optional embodiment, the seaweed and / or brackish water diatoms include silicon-rich Centroidea diatoms and Pennate diatoms;

[0014] Preferably, the Centroidea diatoms include Thalassiosira;

[0015] Preferably, the Pinnate diatoms include at least one of Nitzschia and Navicula.

[0016] In an optional embodiment, the culture temperature is 20-30° C., and the culture time is 60-90 days.

[0017] In an optional embodiment, the diluted urine is obtained by diluting excreted urine 5 to 10 times.

[0018] In an optional embodiment, the organic matter content in the improved lunar soil is 0.5-1.4%, and the passivation rate of heavy metal ions is greater than 20%.

[0019] In a second aspect, the present invention provides a modified lunar soil, which is prepared using the lunar soil improvement method as described in any of the aforementioned embodiments.

[0020] In a third aspect, the present invention provides a method for planting crops in lunar soil, wherein crop seeds are planted in the improved lunar soil as described in the aforementioned embodiment, and the crop seeds germinate in 12 to 30 days.

[0021] In an alternative embodiment, the crop seeds include rice seeds.

[0022] The present invention has the following beneficial effects:

[0023] The method for improving lunar soil provided by the present invention is aimed at the problems that the existing lunar base cannot achieve self-sufficiency in food and vegetables, and the existing lunar soil improvement method still cannot achieve crop cultivation. A method is provided based on diatoms to destroy lunar soil rock minerals and provide organic nutrition to form a cultivable soil for crops. Specifically, the present invention uses a mixture of waste (urine) excreted by aviation personnel and simulated lunar soil as a diatom culture medium, wherein diatoms can destroy lunar soil rock minerals and provide organic nutrition during the growth process to form cultivable soil for crops, etc. In addition, diatoms can also increase pH to precipitate heavy metals, thereby reducing the entry of heavy metals into crops and fruits. In the present invention, using diluted urine as a culture medium can not only achieve waste regeneration, but also enable diatoms to reproduce rapidly and release oxygen. Therefore, the present invention not only does not consume oxygen, but also provides an oxygen source for air travel and lunar soil bases, reduces carbon dioxide concentration, and can also make lunar soil an effective plant cultivation matrix, thereby achieving large-scale lunar soil improvement and crop cultivation, so as to achieve the long-term personnel garrison and stable operation of lunar soil and other bases. The nutritional supply required. The invention has the advantages of high efficiency, ease of implementation, low cost, and easy large-scale and wide-range application. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0025] Figure 1 This is a morphological image of the simulated lunar soil before improvement provided in Example 8;

[0026] Figure 2 This is a morphological diagram of the improved simulated lunar soil provided in Example 8;

[0027] Figure 3 The state diagram of the rice seed application on day 0 in the improved simulation provided in Example 8;

[0028] Figure 4 The state diagram of the rice seeds on the 12th day in the improved simulation provided in Example 8. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.

[0030] The present invention provides a method for improving lunar soil, which comprises: mixing diluted urine and simulated lunar soil at a liquid-solid ratio of 1 ml: 2-10 g to obtain a mixture, and adding 10 3 ~10 5 Diatom strains were added in a ratio of 1 diatom strain to 2 diatom strains, and continuous culture was carried out under carbon dioxide conditions to obtain improved lunar soil.

[0031] The culture temperature is 20-30° C., and the culture time is 60-90 days. During the culture process, the fluorescent lamp is used for 24 hours of irradiation and then turned off for 24 hours for culture.

[0032] The present invention uses a mixture of human excrement (urine) and simulated lunar soil (standard simulated lunar soil provided by the Institute of Geochemistry, Chinese Academy of Sciences) as a diatom culture medium, wherein diatoms are a silicon-requiring organism that has a unique preference for silicon, and therefore must obtain silicon sources from the environment in order to grow normally. In addition, based on photosynthesis, diatoms can form organic components and provide sufficient nutrition. Therefore, diatoms can destroy lunar soil rock minerals, provide organic nutrition, and form soil that can be cultivated for crops, and with the help of their unique pH-raising function, heavy metals and the like are precipitated, thereby reducing the entry of heavy metals into crops and fruits. In the present invention, diluted urine is obtained by diluting excreted urine by 5 to 10 times. Using diluted urine as a culture medium can not only achieve waste regeneration, but also enable diatoms to reproduce rapidly, provide oxygen, provide an oxygen source for air travel and lunar soil bases, and reduce carbon dioxide concentrations.

[0033] Therefore, by using the waste excreted by aviation personnel and lunar soil to cultivate diatoms, it is not only possible to effectively purify the environment of aircraft, lunar bases, etc., provide oxygen, and reduce carbon dioxide concentration, but also to make the lunar soil an effective plant cultivation matrix, thereby realizing large-scale lunar soil improvement and crop cultivation, so as to achieve the long-term personnel stationing and stable operation of lunar soil and other bases. The preparation method of the present invention has the advantages of high efficiency, low cost, and easy large-scale and wide-range application. In addition, the carbon dioxide condition in the present invention uses the waste gas exhaled by astronauts as the carbon dioxide source.

[0034] In other embodiments of the present invention, the liquid-solid ratio of diluted urine and simulated lunar soil is 1 ml: 2 to 20 g, for example, it can be any one of 1 ml: 2 g, 1 ml: 3 g, 1 ml: 5 g, 1 ml: 8 g, 1 ml: 10 g, 1 ml: 15 g, 1 ml: 20 g or a range value between any two of them. Preferably, the liquid-solid ratio of diluted urine and simulated lunar soil is 1 ml: 2 to 10 g, more preferably, the liquid-solid ratio of diluted urine and simulated lunar soil is 1 ml: 2 to 5 g.

[0035] In other embodiments of the present invention, 103 ~10 5 Diatom strains, for example, 10 3 , 10 4 , 10 5 Any one of them or the range between any two, preferably 10 4 , 10 5 When the amount of diatom strain added is too small, the diatom population will grow slowly and be easily affected by environmental microorganisms. When the amount of diatom strain added is too large, it will lead to resource competition among individuals in the population and growth will be restricted.

[0036] Specifically, the diatom strain used in the method for improving lunar soil provided by the present invention is a marine algae and / or brackish water diatom that has been domesticated for tolerance. Since urine has too high a salt content, diatoms cannot survive if directly placed in it. Therefore, the diatom strain provided by the present invention is a tolerant strain formed after long-term domestication.

[0037] Among them, the method of tolerance domestication includes mixing urine diluted 5 to 10 times with diatom culture solution in a first volume ratio of 1:10, culturing diatoms, and obtaining corresponding algae species after continuous culture for 5-10 generations; then placing the algae species in urine diluted 5 to 10 times and diatom culture solution (mixed in a second volume ratio of 1:5), culturing for 5-10 generations to obtain corresponding algae species, repeating the above process, the volume of urine in the first volume ratio is less than the volume of the diatom culture solution, and the volume ratio of the concentration of urine diluted 5 to 10 times to the concentration of diatom culture solution is gradually increased until there is no diatom culture solution for culture, to 1:2.5, 1:1, 2:1, 5:1, 10:1 and no diatom culture solution. At this time, the diatoms that can still grow normally are the domesticated diatoms.

[0038] Preferably, the changing trend of the volume ratio gradually changes from 1:9-11, 1:4-6, 1:2-3, 1:1, 1.5-2.5:1, 4-6:1, 9-11:1 and diatom-free culture solution.

[0039] The diatom culture medium was purchased from Shanghai Guangyu.

[0040] Further, the seaweed and / or brackish water diatoms in the present invention include silicon-rich Centrodiatoms and Pennate diatoms; preferably, the Centrodiatoms include Thalassiosira; the Pennate diatoms include at least one of Nitzschia and Navicula. The seaweed and / or brackish water diatoms in the present invention are natural diatoms collected directly, and the specific collection method includes a plankton net, and the collection area includes Huizhou Kaozhouyang and Daya Bay.

[0041] In the present invention, seawater algae and / or brackish water diatoms are selected as the source of diatom strains, and freshwater algae cannot be used. When freshwater algae are put into a mixture of diluted urine and simulated lunar soil, the survival time of freshwater algae is short and it cannot effectively play an improvement role.

[0042] By modifying the lunar soil through the above-mentioned lunar soil modification method, the organic matter content in the obtained modified lunar soil can reach 0.5-1.4%, and the heavy metal ion passivation rate is greater than 20%. By increasing the organic matter content in the modified lunar soil and reducing the heavy metal ion content, the modified lunar soil is more suitable for crop growth. In addition, it is worth noting that the present invention utilizes the growth of diatoms to destroy the rock minerals in the lunar soil. It etches the surface of the rock minerals and turns the sharp, blade-like lunar soil minerals into fluffy minerals, which no longer pose a threat to the root system.

[0043] The modified lunar soil obtained after modification can be used as a planting matrix for crops. Therefore, the present invention also provides a method for planting crops in lunar soil, which comprises planting crop seeds in the modified lunar soil, and the crop seeds germinate in 12 to 30 days. The crop seeds include but are not limited to rice seeds.

[0044] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

[0045] Example 1

[0046] This embodiment provides a method for improving lunar soil, which includes diluting urine 5 times to obtain diluted urine, mixing the diluted urine with simulated lunar soil at a liquid-solid ratio of 1 ml:20 g to obtain a mixture, and adding 10 3 Diatom strains were added in a ratio of 1.5 diatom strains (Navicula), and continuous culture was carried out under carbon dioxide conditions at a temperature of 20°C and a culture time of 60 days to obtain improved lunar soil.

[0047] The tolerance domestication method of Navicula comprises: mixing urine diluted ten times with a Navicula culture solution at a volume ratio of 1:10, culturing, and obtaining the corresponding Navicula species after continuous culturing for 5-10 generations; then placing the algae species in urine diluted ten times and a diatom culture solution (mixed at a volume ratio of 1:5), and obtaining the corresponding Navicula species after culturing for 5-10 generations, repeating the above process, and gradually increasing the concentration of the urine diluted ten times and the diatom culture solution to 1:2.5, 1:1, 2:1, 5:1, 10:1 and no diatom culture solution. The Navicula that can still grow normally at this time is the domesticated Navicula.

[0048] Example 2

[0049] This embodiment provides a method for improving lunar soil, which includes diluting urine 5 times to obtain diluted urine, mixing the diluted urine with simulated lunar soil at a liquid-solid ratio of 1 ml:10 g to obtain a mixture, and adding 10 3 Diatom strains were added in a ratio of 1.5 diatom strains (Navicula), and continuous culture was carried out under carbon dioxide conditions at a temperature of 20°C and a culture time of 60 days to obtain improved lunar soil.

[0050] Example 3

[0051] This embodiment provides a method for improving lunar soil, which includes diluting urine 5 times to obtain diluted urine, mixing the diluted urine with simulated lunar soil at a liquid-solid ratio of 1 ml:5 g to obtain a mixture, and adding 10 3 Diatom strains were added in a ratio of 1.5 diatom strains (Navicula), and continuous culture was carried out under carbon dioxide conditions at a temperature of 20°C and a culture time of 60 days to obtain improved lunar soil.

[0052] Example 4

[0053] This embodiment provides a method for improving lunar soil, which includes diluting urine 5 times to obtain diluted urine, mixing the diluted urine with simulated lunar soil at a liquid-solid ratio of 1 ml:2 g to obtain a mixture, and adding 10 3 Diatom strains were added in a ratio of 1.5 diatom strains (Navicula), and continuous culture was carried out under carbon dioxide conditions at a temperature of 20°C and a culture time of 60 days to obtain improved lunar soil.

[0054] Example 5

[0055] This embodiment provides a method for improving lunar soil, which includes diluting urine 10 times to obtain diluted urine, mixing the diluted urine with simulated lunar soil at a liquid-solid ratio of 1 ml:2 g to obtain a mixture, and adding 10 3 Diatom strains were added in a ratio of 1.5 diatom strains (Navicula), and continuous culture was carried out under carbon dioxide conditions at a temperature of 20°C and a culture time of 60 days to obtain improved lunar soil.

[0056] Example 6

[0057] This embodiment provides a method for improving lunar soil, which includes diluting urine 5 times to obtain diluted urine, mixing the diluted urine with simulated lunar soil at a liquid-solid ratio of 1 ml:2 g to obtain a mixture, and adding 10 3 Diatom strains were added in a ratio of 1.5 diatom strains (Navicula), and continuous culture was carried out under carbon dioxide conditions at a temperature of 20°C and a culture time of 90 days to obtain improved lunar soil.

[0058] Example 7

[0059] This embodiment provides a method for improving lunar soil, which includes diluting urine 5 times to obtain diluted urine, mixing the diluted urine with simulated lunar soil at a liquid-solid ratio of 1 ml:2 g to obtain a mixture, and adding 10 4 Diatom strains were added in a ratio of 1.5 diatom strains (Navicula), and continuous culture was carried out under carbon dioxide conditions at a temperature of 20°C and a culture time of 90 days to obtain improved lunar soil.

[0060] Example 8

[0061] This embodiment provides a method for improving lunar soil, which includes diluting urine 5 times to obtain diluted urine, mixing the diluted urine with simulated lunar soil at a liquid-solid ratio of 1 ml:2 g to obtain a mixture, and adding 10 5 Diatom strains were added in a ratio of 1.5 diatom strains (Navicula), and continuous culture was carried out under carbon dioxide conditions at a temperature of 20°C and a culture time of 90 days to obtain improved lunar soil.

[0062] Example 9

[0063] This embodiment provides a method for improving lunar soil, which includes diluting urine 5 times to obtain diluted urine, mixing the diluted urine with simulated lunar soil at a liquid-solid ratio of 1 ml:2 g to obtain a mixture, and adding 10 5 Diatom strains were added in a ratio of 1.5 diatom strains (Navicula), and continuous culture was carried out under carbon dioxide conditions at a temperature of 20°C and a culture time of 60 days to obtain improved lunar soil.

[0064] Example 10

[0065] This embodiment provides a method for improving lunar soil, which includes diluting urine 5 times to obtain diluted urine, mixing the diluted urine with simulated lunar soil at a liquid-solid ratio of 1 ml:2 g to obtain a mixture, and adding 10 5 Diatom strains were added in a ratio of 1.5 diatom strains (Nitzschia algae), and continuous culture was carried out under carbon dioxide conditions at a temperature of 20°C and a culture time of 90 days to obtain improved lunar soil.

[0066] Embodiment 11

[0067] This embodiment provides a method for improving lunar soil, which includes diluting urine 5 times to obtain diluted urine, mixing the diluted urine with simulated lunar soil at a liquid-solid ratio of 1 ml:2 g to obtain a mixture, and adding 10 5Diatom strains were added in a ratio of 100 μg / cm2 and 100 μg / cm2, and continuous culture was carried out under carbon dioxide conditions at a temperature of 20°C and a culture time of 90 days to obtain improved lunar soil.

[0068] Comparative Example 1

[0069] This comparative example is basically the same as Example 8, with the only difference being that no diatom strain is added in this comparative example, and the specific steps include: diluting urine 5 times to obtain diluted urine, mixing the diluted urine with simulated lunar soil at a liquid-solid ratio of 1 ml:2 g to obtain a mixture, and continuously culturing the mixture under carbon dioxide conditions at a temperature of 20°C for 90 days to obtain improved lunar soil.

[0070] Comparative Example 2

[0071] This comparative example is basically the same as comparative example 1, with the only difference being that the dilution multiple of urine in this comparative example is different. The specific steps include: diluting urine 10 times to obtain diluted urine, mixing the diluted urine with simulated lunar soil at a liquid-solid ratio of 1 ml:2 g to obtain a mixture, and continuously culturing the mixture under carbon dioxide conditions at a temperature of 20°C for 90 days to obtain improved lunar soil.

[0072] Comparative Example 3

[0073] Only one type of lunar soil is provided in this comparative example.

[0074] Comparative Example 4

[0075] This comparative example is basically the same as Example 8, except that in this comparative example, the diatom strain is different. The specific steps include: diluting urine 5 times to obtain diluted urine, mixing the diluted urine with simulated lunar soil at a liquid-solid ratio of 1 ml:2 g to obtain a mixture, and adding 10 5 Diatom strains were added in a ratio of 100 μg / cm2 (Cyclotella meni (monoaquatic algae)), and continuous culture was carried out under carbon dioxide conditions at a temperature of 20°C and a culture time of 90 days to obtain improved lunar soil.

[0076] Comparative Example 5

[0077] This comparative example is basically the same as Example 8, except that in this comparative example, Navicula was not subjected to tolerance acclimatization.

[0078] Comparative Example 6

[0079] This comparative example is basically the same as Example 8, except that the Navicula in this comparative example is selected from freshwater areas and is domesticated according to the tolerance domestication method of Example 8.

[0080] Comparative Example 7

[0081] This comparative example is basically the same as Example 8, except that 10 6 Diatom strains were added in a ratio of 1:1 diatom strain (Navicula).

[0082] In order to more clearly illustrate the above embodiments and comparative examples, the statistics are as follows:

[0083]

[0084]

[0085] The above examples and comparative examples provide the organic matter content and heavy metal ion passivation rate of the improved lunar soil. Rice seeds are planted in the above improved lunar soil and the time required for seed germination is recorded.

[0086] Among them, the potassium dichromate method is used to determine the organic matter content: weigh about 0.1g of powder sample and add 25ml of 0.4mol / L potassium dichromate solution. Place it in a 100℃ water bath for 30 minutes, shake it several times every ten minutes or so. Add concentrated hydrochloric acid and o-phenanthroline indicator and shake it evenly, and titrate it with ferrous sulfate solution.

[0087] The method for detecting the passivation rate of heavy metal Cd includes: weighing 5.000 g of soil sample into a 100 mL centrifuge tube, adding 50 mL of 0.1 mol L - -1 CaCl2 extractant, at 25℃, 200r min -1 Oscillate for 2 h and then at 3000 r min -1 Centrifuge for 20 min and filter the supernatant to detect active cadmium.

[0088] Take 0.10g of air-dried soil that has passed through a 100-mesh sieve and put it in a conical flask, add 0.1mL of deionized water, 3mL of HCl and 1mL of HNO3, let it stand for 12h and then heat it at 350℃ for 1h, then add 1mL of HClO4 to boil until the solid is white, filter it and measure the total cadmium content.

[0089] The Cd content was measured using a Shimadzu AA-6880 atomic absorption spectrophotometer.

[0090] The test results are as follows:

[0091]

[0092] As can be seen from the above table, in Examples 1-4, when the amount of diatoms added is constant, in the mixture of lunar soil and diluted urine, the amount of lunar soil added is about 0.01%, and the modified effect of diluted urine and diatoms is better. It can be seen from Examples 4-5 that when the amount of diatoms and lunar soil added is constant, the greater the dilution multiple of urine, the lower the organic matter content in the modified lunar soil, but the passivation rate of heavy metal examples is improved to a certain extent. It can be seen from the above Examples 1-5 that although Examples 1-5 cannot effectively germinate rice seeds, they can improve lunar soil to a certain extent. Further, in Example 6, by increasing the cultivation time of diatoms in Example 4, it can be seen that the organic matter content and the passivation rate of heavy metal examples in the lunar soil are significantly improved, and rice begins to germinate 21 days after planting. Subsequent Examples 7-8 gradually increase the concentration of diatoms on the basis of Example 6. It can be seen that the organic matter content and the passivation rate of heavy metal examples in the lunar soil increase with the increase of diatom concentration, and the germination time after rice planting is also shortened. In Example 9, the culture time of Example 8 was shortened, and it can be seen that the effect is reduced, but it still has a better effect. Other diatoms were selected in Examples 10-11, and they still have excellent effects. In Comparative Examples 1 and 2, no diatoms were added, and in Comparative Example 3, only one lunar soil was provided. By comparison, it can be seen that the lunar soil and diluted urine were directly mixed. It can be seen that no matter how many times the diluted urine was diluted, it had no improvement effect on the lunar soil. In Comparative Examples 4-6, other algae were selected, such as freshwater algae that had been domesticated with tolerance, undomesticated boat algae, or boat algae in freshwater areas, and it was found that they still could not effectively modify the lunar soil. In Comparative Example 7, the concentration of tolerant domesticated boat algae was too high. At this time, a certain improvement effect could be achieved, but compared with Example 8, its effect was reduced. This fully proves that the concentration of diatoms is not the higher the better.

[0093] from Figure 1 and Figure 2 It can be seen that the mineral particle morphology of the simulated lunar soil has changed before and after modification. Figure 1 The minerals in the unmodified simulated lunar soil are extremely sharp, like blades, and can easily damage organs such as roots; but after being modified by diatoms, its surface is fully etched, becoming fluffy and no longer posing a threat to roots.

[0094] from Figure 3 and Figure 4 It can be seen that after the rice seeds were planted in the above-mentioned improved lunar soil, the rice seeds grew smoothly and began to germinate after 12 days.

[0095] In summary, the method for improving lunar soil provided by the present invention is aimed at the problems that the existing lunar base cannot achieve self-sufficiency in food and vegetables, and the existing lunar soil improvement method still cannot achieve crop cultivation. A method is provided based on diatoms to destroy lunar soil rock minerals and provide organic nutrition to form a cultivable soil for crops. Specifically, the present invention uses a mixture of waste (urine) excreted by aviation personnel and simulated lunar soil as a diatom culture medium, wherein diatoms can destroy lunar soil rock minerals and provide organic nutrition during the growth process to form cultivable soil for crops, etc. In addition, diatoms can also increase pH to precipitate heavy metals, thereby reducing the entry of heavy metals into crops and fruits. In the present invention, using diluted urine as a culture medium can not only achieve waste regeneration, but also enable diatoms to reproduce rapidly, provide oxygen, provide an oxygen source for air travel and lunar soil bases, and reduce carbon dioxide concentration. It can also make lunar soil an effective plant cultivation matrix, thereby achieving large-scale lunar soil improvement and crop cultivation, so as to achieve the long-term personnel garrison and stable operation of lunar soil and other bases. The nutrition supply required. The present invention has the advantages of high efficiency, low cost, easy large-scale and wide-range application.

[0096] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for improving lunar soil, characterized in that: It includes: The diluted urine and simulated lunar soil were mixed at a liquid-solid ratio of 1 ml: 2-20 g to obtain a mixture. 10 3 ~10 5 Diatom strains were added in a ratio of 1 diatom strain to 2 diatom strains, and continuous culture was carried out under carbon dioxide conditions to obtain improved lunar soil.

2. The method for improving lunar soil according to claim 1, characterized in that: The diatom strain is marine algae and / or brackish water diatom that has been domesticated for tolerance.

3. The method for improving lunar soil according to claim 2, characterized in that: The tolerance domestication method comprises mixing urine diluted 5 to 10 times with a diatom culture solution in a first volume ratio, culturing diatoms, and obtaining corresponding algae species after continuous culturing for 5 to 10 generations; then placing the algae species in urine diluted 5 to 10 times and mixing it with a diatom culture solution in a second volume ratio, culturing for 5 to 10 generations, obtaining corresponding algae species, and repeating the above process, wherein the volume of urine in the first volume ratio is smaller than the volume of the diatom culture solution, and the volume ratio of the concentration of urine diluted 5 to 10 times to the diatom culture solution is gradually increased until the diatom culture solution is not used for culturing, and the diatoms that can still grow normally are the domesticated diatoms; Preferably, the changing trend of the volume ratio gradually changes from 1:9-11, 1:4-6, 1:2-3, 1:1, 1.5-2.5:1, 4-6:1, 9-11:1 and diatom-free culture solution.

4. The method for improving lunar soil according to claim 2, characterized in that: The seaweed and / or brackish water diatoms include silicon-rich Centroidea diatoms and Pennate diatoms; Preferably, the Centroidea diatoms include Thalassiosira; Preferably, the Pinnate diatoms include at least one of Nitzschia and Navicula.

5. The method for improving lunar soil according to claim 1, characterized in that: The culture temperature is 20-30° C. and the culture time is 60-90 days.

6. The method for improving lunar soil according to claim 1, characterized in that: The diluted urine is obtained by diluting the excreted urine 5 to 10 times.

7. The method for improving lunar soil according to claim 1, characterized in that: The organic matter content in the improved lunar soil is 0.5-1.4%, and the passivation rate of heavy metal ions is greater than 20%.

8. An improved lunar soil, characterized in that: It is prepared by the lunar soil improvement method as described in any one of claims 1-7.

9. A method for planting crops using lunar soil, characterized in that: Crop seeds are planted in the improved lunar soil as described in claim 8, and the crop seeds germinate in 12 to 30 days.

10. The method for planting crops with lunar soil according to claim 9, characterized in that: The crop seeds include rice seeds.

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