A method of improving lunar soil, improved lunar soil and a method of growing crops in lunar soil

Abstract

The application discloses a lunar soil improvement method, improved lunar soil and a lunar soil planting crop method, and relates to the technical field of lunar soil utilization. The lunar soil improvement method comprises the following steps: mixing diluted urine and simulated lunar soil according to a liquid-solid ratio of 1ml:2-20g to obtain a mixture, adding 10 3 ~10 5 silica fungus strains into 1ml of the mixture, continuously culturing under a carbon dioxide condition, and obtaining improved lunar soil. The lunar soil improvement method provided by the application can not only realize waste regeneration, but also can make the silica fungus breed rapidly, provide oxygen, reduce the carbon dioxide concentration, and make the lunar soil become an effective plant cultivation substrate, so that large-scale lunar soil improvement and crop cultivation are realized, and the required nutrition supply for long-term personnel garrison and stable operation of a base such as the lunar soil is realized. The application has the advantages of high efficiency, low cost, easy large-scale and wide-range application, and the like.

Description

Technical Field

[0001] This invention relates to the field of in-situ utilization of lunar soil, and more specifically, to a method for improving lunar soil, a method for improving lunar soil, and a method for planting crops on lunar soil. Background Technology

[0002] Lunar soil (or lunar soil for short) refers to the soil unique to the moon. It is the result of space weathering, and the mineral powder that makes up lunar soil is mainly formed by the impact and breakup of meteorites.

[0003] Lunar soil has a complex chemical composition, rock types, and mineral composition; each sample consists of a variety of rocks and minerals. It is rich in helium-3, which, because it does not produce neutrons during fusion and has low radioactivity, is considered a highly efficient, clean, safe, and inexpensive fuel for controlled nuclear fusion power generation. Lunar soil contains no organic nutrients and is extremely dry, making it unsuitable for growing plants. However, lunar soil is helpful for studying the matter and energy of the solar system, allowing humanity to better understand the history of the moon and the evolution of the Earth-Moon system. Furthermore, human understanding and research of lunar soil is an indispensable foundation for lunar exploration, as well as the future establishment of lunar bases and the utilization of the moon.

[0004] The establishment of a lunar base necessitates the supply of food and vegetables for the safety of astronauts. However, transporting these supplies from Earth is extremely costly and unsustainable. Therefore, crop cultivation is crucial for the establishment and long-term stable operation of lunar bases. However, directly utilizing lunar soil for crop growth and harvesting is not feasible. This is because lunar soil has low mineral porosity, making nutrient supply difficult; sharp mineral particles hinder crop development; high heavy metal content toxicizes crops; and the lack of microorganisms and organic matter makes nutrient supply challenging. Lunar soil improvement is an essential step in crop cultivation and urgently needs to be implemented.

[0005] Existing research involves adding organic components to lunar soil and conducting aerobic fermentation at a certain temperature while adding a large amount of water to produce organic nutrients usable by plants, which can also promote wheat seedling germination. However, this improvement has the following problems: 1) It only improves the lack of organic nutrients in lunar soil, but cannot address the problem of sharp minerals that damage the root system; 2) This process requires the addition of a large amount of fresh water, which is well known to be the scarcest resource on the moon, making it difficult to meet and potentially wasteful; 3) Aerobic fermentation is required, and oxygen is an essential raw material for life support in space stations and lunar bases. While ensuring the use of personnel, oxygen is difficult to reuse, thus hindering lunar soil improvement; 4) High heavy metal content and the inability to supply inorganic nutrients pose risks to the produced fruits, vegetables, and grains; crops and fruits grown in a high-heavy-metal environment will cause toxicity to personnel on the base; 5) The need for a certain temperature for fermentation leads to energy depletion at the base. In conclusion, the above improvement scheme is difficult to implement and use on a large scale.

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

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

[0008] This invention is implemented as follows:

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

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

[0011] In an optional embodiment, the tolerance acclimatization method includes mixing urine diluted 5-10 times with diatom culture medium at a first volume ratio, culturing diatoms, and obtaining the corresponding algal species after 5-10 generations of continuous cultivation; then placing the algal species in urine diluted 5-10 times with diatom culture medium at a second volume ratio, culturing for 5-10 generations to obtain the corresponding algal species, and repeating the above process. In the first volume ratio, the volume of urine is smaller than the volume of diatom culture medium, and the volume ratio of urine diluted 5-10 times to diatom culture medium is gradually increased until no diatom culture medium is used for cultivation. Diatoms that can still grow normally are acclimatized diatoms.

[0012] Preferably, the volume ratio changes gradually 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 medium.

[0013] In an optional embodiment, the marine algae and / or brackish water diatoms include silicon-rich centroclass diatoms and pinnate class diatoms;

[0014] Preferably, the central diatom includes *Strombocybene natans*;

[0015] Preferably, the feathery diatoms include at least one of rhomboid algae and nautiloid algae.

[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 the excreted urine by 5 to 10 times.

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

[0019] Secondly, the present invention provides an improved lunar soil, which is prepared by the lunar soil improvement method described in any of the foregoing embodiments.

[0020] Thirdly, 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 foregoing embodiments, and the crop seeds germinate in 12 to 30 days.

[0021] In an optional implementation, the crop seed includes rice seeds.

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

[0023] This invention provides a method for improving lunar soil that addresses the problems of existing lunar bases being unable to achieve self-sufficiency in food and vegetables, and existing lunar soil improvement methods still being unable to support crop cultivation. It offers a method based on diatoms breaking down lunar soil rocks and minerals, providing organic nutrients, and transforming it into cultivable soil for crops. Specifically, this invention uses a mixture of astronaut excrement (urine) and simulated lunar soil as a diatom culture medium. During its growth, the diatoms break down lunar soil rocks and minerals, providing organic nutrients to create cultivable soil for crops. Furthermore, the diatoms can raise the pH, causing heavy metals to precipitate, thereby reducing the amount of heavy metals entering crops and fruits. Using diluted urine as a culture medium in this invention not only achieves waste regeneration but also allows for rapid diatom reproduction and oxygen release. Therefore, this 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 makes lunar soil an effective plant cultivation substrate. This enables large-scale lunar soil improvement and crop cultivation, ensuring the nutrient supply required for long-term personnel presence and stable operation of lunar soil bases. This invention has the advantages of high efficiency, low cost, and ease of large-scale and wide-ranging application. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a morphological diagram of simulated lunar soil before improvement, provided in Example 8.

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

[0027] Figure 3 A state diagram of day 0 in the improved simulation provided in Example 8, in which rice seeds were applied;

[0028] Figure 4 A state diagram of rice seeds applied on day 12 in the improved simulation provided in Example 8. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0030] This invention provides a method for improving lunar soil, comprising: mixing diluted urine with simulated lunar soil at a liquid-to-solid ratio of 1 ml: 2-10 g to obtain a mixture, and adding 10 g of [unspecified substance] per 1 ml of the mixture. 3 ~10 5 Diatom strains were added at a ratio of 1:1, and the mixture was continuously cultured under carbon dioxide conditions to obtain improved lunar soil.

[0031] The cultivation temperature was 20–30℃, and the cultivation time was 60–90 days. During the cultivation process, the plants were irradiated with fluorescent lamps for 24 hours, followed by a 24-hour cooling period.

[0032] This 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. Diatoms are silicon-dependent organisms with a unique preference for silicon, thus requiring silicon sources from the environment for normal growth. Furthermore, they can form organic components and provide ample nutrition through photosynthesis. Therefore, diatoms can disrupt lunar soil rocks and minerals, provide organic nutrients, and create cultivable soil for crops. Their unique pH-raising function also helps precipitate heavy metals, thereby reducing their entry into crops and fruits. In this invention, the diluted urine is obtained by diluting excreted urine 5-10 times. Using diluted urine as a culture medium not only achieves waste regeneration but also allows diatoms to multiply rapidly, providing oxygen for air travel and lunar soil bases, while reducing carbon dioxide concentration.

[0033] Therefore, using astronaut excrement and lunar soil for diatom cultivation can not only effectively purify the environment of spacecraft and lunar bases, providing oxygen and reducing carbon dioxide concentration, but also make lunar soil an effective plant cultivation substrate. This enables large-scale lunar soil improvement and crop cultivation, ensuring the nutrient supply needed for long-term personnel presence and stable operation of lunar bases. The preparation method of this invention has advantages such as high efficiency, low cost, and ease of large-scale and wide-ranging application. Furthermore, the carbon dioxide condition in this invention uses astronaut exhaled waste gas as the carbon dioxide source.

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

[0035] In other embodiments of the invention, 10 ppm is added to every 1 ml of mixture.3 ~10 5 10 diatom strains, for example, can be 10 3 10 4 10 5 The range of values ​​between any one or any two of them is preferably 10. 4 10 5 When too few diatom strains are added, the diatom population grows slowly and is easily affected by environmental microorganisms. When too many diatom strains are added, it leads to resource competition among individuals in the population, thus limiting growth.

[0036] Specifically, the diatom strains used in the lunar soil improvement method provided by this invention are marine algae and / or brackish water diatoms that have undergone tolerance acclimatization. Since diatoms cannot survive if directly introduced into urine due to its high salt content, the diatom strains provided by this invention are acclimatized strains that have become tolerant over a long period.

[0037] The tolerance acclimatization method includes mixing urine diluted 5-10 times with diatom culture medium at a first volume ratio of 1:10, culturing diatoms, and obtaining the corresponding algal species after 5-10 generations of continuous cultivation; then placing the algal species in urine diluted 5-10 times with diatom culture medium at a second volume ratio of 1:5, culturing for 5-10 generations to obtain the corresponding algal species, and repeating the above process. In the first volume ratio, the volume of urine is smaller than the volume of diatom culture medium. The volume ratio of the concentration of urine diluted 5-10 times to the concentration of diatom culture medium is gradually increased until there is no diatom culture medium for cultivation, up to 1:2.5, 1:1, 2:1, 5:1, 10:1 and no diatom culture medium. The diatoms that can still grow normally at this point are the acclimatized diatoms.

[0038] Preferably, the volume ratio changes gradually 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 medium.

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

[0040] Furthermore, the marine algae and / or brackish water diatoms in this invention include silicon-rich centrodiatoms and pinnate diatoms; preferably, centrodiatoms include *Strombyx mori*; pinnate diatoms include at least one of *Rhizophora* and *Navicula*. The marine algae and / or brackish water diatoms in this invention are directly collected natural diatoms, specifically collected using planktonic nets, and collected in the Kaozhou Bay and Daya Bay areas of Huizhou.

[0041] In this invention, marine algae and / or brackish water diatoms are selected as the source of diatom strains. Freshwater algae cannot be used. When freshwater algae are added to a mixture of diluted urine and simulated lunar soil, the survival time of freshwater algae is short, and they cannot effectively play a role in improvement.

[0042] By modifying lunar soil using the methods described above, the organic matter content of the improved lunar soil can reach 0.5-1.4%, and the heavy metal ion passivation rate can be greater than 20%. By increasing the organic matter content and reducing the heavy metal ion content, the improved lunar soil becomes more suitable for crop growth. In addition, it is worth noting that this invention utilizes the growth of diatoms to destroy the rock minerals in the lunar soil. Diatoms etch the surface of the rock minerals, transforming the sharp, blade-like lunar soil minerals into fluffy minerals that no longer pose a threat to roots.

[0043] The modified lunar soil can be used as a planting substrate for crops. Therefore, this invention also provides a method for planting crops in lunar soil, which includes planting crop seeds in the modified lunar soil, and the crop seeds germinating 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 will be further described in detail below with reference to embodiments.

[0045] Example 1

[0046] This embodiment provides a method for improving lunar soil, which includes diluting urine five times to obtain diluted urine, mixing the diluted urine with simulated lunar soil at a liquid-to-solid ratio of 1 ml: 20 g to obtain a mixture, and adding 10 g of [unspecified substance] per 1 ml of the mixture. 3 A certain proportion of diatom strains (Navicula) were added to the diatom strains, and the mixture was continuously cultured under carbon dioxide conditions at a temperature of 20°C for 60 days to obtain improved lunar soil.

[0047] The tolerance acclimatization method for *Navicula* includes: mixing urine diluted 10 times with *Navicula* culture medium at a volume ratio of 1:10, culturing for 5-10 generations to obtain the corresponding *Navicula* species; then placing the species in urine diluted 10 times with diatom culture medium (mixed at a volume ratio of 1:5), culturing for 5-10 generations to obtain the corresponding *Navicula* species, repeating the above process, gradually increasing the concentration of urine diluted 10 times with diatom culture medium to 1:2.5, 1:1, 2:1, 5:1, 10:1 and no diatom culture medium, and the *Navicula* species that can still grow normally at this point are the acclimatized *Navicula*.

[0048] Example 2

[0049] This embodiment provides a method for improving lunar soil, which includes diluting urine five times to obtain diluted urine, mixing the diluted urine with simulated lunar soil at a liquid-to-solid ratio of 1 ml: 10 g to obtain a mixture, and adding 10 g of [unspecified substance] per 1 ml of the mixture. 3 A certain proportion of diatom strains (Navicula) were added to the diatom strains, and the mixture was continuously cultured under carbon dioxide conditions at a temperature of 20°C for 60 days to obtain improved lunar soil.

[0050] Example 3

[0051] This embodiment provides a method for improving lunar soil, which includes diluting urine by 5 times to obtain diluted urine, mixing the diluted urine with simulated lunar soil at a liquid-to-solid ratio of 1 ml: 5 g to obtain a mixture, and adding 10 g of iodine per 1 ml of the mixture. 3 A certain proportion of diatom strains (Navicula) were added to the diatom strains, and the mixture was continuously cultured under carbon dioxide conditions at a temperature of 20°C for 60 days to obtain improved lunar soil.

[0052] Example 4

[0053] This embodiment provides a method for improving lunar soil, which includes diluting urine five times to obtain diluted urine, mixing the diluted urine with simulated lunar soil at a liquid-to-solid ratio of 1 ml: 2 g to obtain a mixture, and adding 10 g of [unspecified substance] per 1 ml of the mixture. 3 A certain proportion of diatom strains (Navicula) were added to the diatom strains, and the mixture was continuously cultured under carbon dioxide conditions at a temperature of 20°C for 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 g of iodine per 1 ml of the mixture. 3 A certain proportion of diatom strains (Navicula) were added to the diatom strains, and the mixture was continuously cultured under carbon dioxide conditions at a temperature of 20°C for 60 days to obtain improved lunar soil.

[0056] Example 6

[0057] This embodiment provides a method for improving lunar soil, which includes diluting urine five times to obtain diluted urine, mixing the diluted urine with simulated lunar soil at a liquid-to-solid ratio of 1 ml: 2 g to obtain a mixture, and adding 10 g of [unspecified substance] per 1 ml of the mixture. 3 A certain proportion of diatom strains (Navicula) were added to the diatom strains, and the mixture was continuously cultured under carbon dioxide conditions at a temperature of 20°C for 90 days to obtain improved lunar soil.

[0058] Example 7

[0059] This embodiment provides a method for improving lunar soil, which includes diluting urine five times to obtain diluted urine, mixing the diluted urine with simulated lunar soil at a liquid-to-solid ratio of 1 ml: 2 g to obtain a mixture, and adding 10 g of [unspecified substance] per 1 ml of the mixture. 4 A certain proportion of diatom strains (Navicula) were added to the diatom strains, and the mixture was continuously cultured under carbon dioxide conditions at a temperature of 20°C for 90 days to obtain improved lunar soil.

[0060] Example 8

[0061] This embodiment provides a method for improving lunar soil, which includes diluting urine five times to obtain diluted urine, mixing the diluted urine with simulated lunar soil at a liquid-to-solid ratio of 1 ml: 2 g to obtain a mixture, and adding 10 g of [unspecified substance] per 1 ml of the mixture. 5 A certain proportion of diatom strains (Navicula) were added to the diatom strains, and the mixture was continuously cultured under carbon dioxide conditions at a temperature of 20°C for 90 days to obtain improved lunar soil.

[0062] Example 9

[0063] This embodiment provides a method for improving lunar soil, which includes diluting urine five times to obtain diluted urine, mixing the diluted urine with simulated lunar soil at a liquid-to-solid ratio of 1 ml: 2 g to obtain a mixture, and adding 10 g of [unspecified substance] per 1 ml of the mixture. 5 A certain proportion of diatom strains (Navicula) were added to the diatom strains, and the mixture was continuously cultured under carbon dioxide conditions at a temperature of 20°C for 60 days to obtain improved lunar soil.

[0064] Example 10

[0065] This embodiment provides a method for improving lunar soil, which includes diluting urine five times to obtain diluted urine, mixing the diluted urine with simulated lunar soil at a liquid-to-solid ratio of 1 ml: 2 g to obtain a mixture, and adding 10 g of [unspecified substance] per 1 ml of the mixture. 5 A certain proportion of diatom strains (rhomboid algae) were added to the diatom strains, and the mixture was continuously cultured under carbon dioxide conditions at a temperature of 20°C for 90 days to obtain improved lunar soil.

[0066] Example 11

[0067] This embodiment provides a method for improving lunar soil, which includes diluting urine five times to obtain diluted urine, mixing the diluted urine with simulated lunar soil at a liquid-to-solid ratio of 1 ml: 2 g to obtain a mixture, and adding 10 g of [unspecified substance] per 1 ml of the mixture. 5A certain proportion of diatom strains (sea chain algae) were added to the diatom strains, and the mixture was continuously cultured under carbon dioxide conditions at a temperature of 20°C for 90 days to obtain improved lunar soil.

[0068] Comparative Example 1

[0069] This comparative example is basically the same as Example 8, except that no diatom strains were added in this comparative example. The specific steps include: diluting urine by 5 times to obtain diluted urine, mixing the diluted urine with simulated lunar soil at a liquid-solid ratio of 1ml:2g to obtain a mixture, and continuously culturing it under carbon dioxide conditions at a culture 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, except that the dilution factor of the urine is different in this comparative example. The specific steps include: diluting the urine by 10 times to obtain diluted urine, mixing the diluted urine with simulated lunar soil at a liquid-solid ratio of 1ml:2g to obtain a mixture, and continuously culturing it under carbon dioxide conditions at a culture temperature of 20℃ for 90 days to obtain improved lunar soil.

[0072] Comparative Example 3

[0073] This comparative example uses only one type of lunar soil.

[0074] Comparative Example 4

[0075] This comparative example is basically the same as Example 8, except that the diatom strain is different in this comparative example. The specific steps include: diluting the urine by 5 times to obtain diluted urine, mixing the diluted urine with simulated lunar soil at a liquid-solid ratio of 1ml:2g to obtain a mixture, and adding 10g of diatomaceous earth per 1ml of the mixture. 5 A certain proportion of diatom strains (Menecium moniliforme (monaquatic algae)) were added to the diatom strains, and the mixture was continuously cultured under carbon dioxide conditions at a temperature of 20°C for 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, the *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 algae in this comparative example are selected from freshwater areas and acclimatized according to the tolerance acclimatization method of Example 8.

[0080] Comparative Example 7

[0081] This comparative example is basically the same as Example 8, except that 10 mg of [unspecified ingredient] is added to every 1 ml of mixture in this comparative example. 6 A certain proportion of diatom strains (Navicula) were added.

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

[0083]

[0084]

[0085] The above embodiments and comparative examples provide the organic matter content and heavy metal ion passivation rate of the improved lunar soil. Rice seeds were also applied to the improved lunar soil, and the time required for seed germination was recorded.

[0086] The organic matter content was determined using the potassium dichromate method: approximately 0.1 g of powdered sample was weighed and added to 25 ml of 0.4 mol / L potassium dichromate solution. The solution was placed in a 100°C water bath for 30 minutes, shaking several times every 10 minutes. Concentrated hydrochloric acid and o-phenanthroline indicator were added, and the mixture was shaken thoroughly before titration 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 solution. - -1 The above-mentioned CaCl2 extractant was used at a constant temperature of 25℃ for 200 rpm. -1 Oscillate for 2 hours under these conditions, then at 3000 rpm. -1 Centrifuge for 20 minutes, filter the supernatant and test for active cadmium.

[0088] Take 0.10g of air-dried soil that has passed through a 100-mesh sieve and place it in an Erlenmeyer flask. Add 0.1mL of deionized water, 3mL of HCl, and 1mL of HNO3. Let it stand for 12 hours, then heat it at 350℃ for 1 hour. Add 1mL of HClO4 and cook until the solid turns white. Filter the solution and then measure the total cadmium content.

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

[0090] The test results are as follows:

[0091]

[0092] As can be seen from the table above, in Examples 1-4, when the amount of diatoms added is constant, the smaller the amount of lunar soil added, the better the modification effect of diluted urine and diatoms on the mixture of lunar soil and diluted urine. Examples 4-5 show that when the amounts of diatoms and lunar soil added are constant, the higher the dilution factor of urine, the lower the organic matter content in the improved lunar soil, but the passivation rate of heavy metals is somewhat increased. Examples 1-5 show that although they cannot effectively induce rice seed germination, they can improve lunar soil to some extent. Furthermore, in Example 6, by increasing the diatom cultivation time in Example 4, it can be seen that the organic matter content and heavy metal passivation rate in the lunar soil are significantly increased, and rice begins to germinate 21 days after planting. Subsequent Examples 7-8 gradually increased the concentration of diatoms based on Example 6. It can be seen that the organic matter content and heavy metal passivation rate in the lunar soil increase with the increase of diatom concentration, while the germination time of rice after planting is also shortened. In Example 9, the cultivation time of Example 8 was shortened, and it can be seen that the effect was reduced, but it still had a good effect. In Examples 10-11, other diatoms were selected, and they still had excellent effects. In Comparative Examples 1 and 2, no diatoms were added, and Comparative Example 3 only provided lunar soil. It can be seen that directly mixing lunar soil with diluted urine, no matter how many times the urine was diluted, had no effect on improving the lunar soil. In Comparative Examples 4-6, other algae were selected, such as freshwater algae that had undergone tolerance acclimation, unacclimated Navicula, or Navicula from freshwater areas. It was found that they still could not effectively modify the lunar soil. In Comparative Example 7, the concentration of acclimated Navicula was too high. At this time, a certain improvement effect could be achieved, but the effect was reduced compared to Example 8. This fully demonstrates that the concentration of diatoms is not necessarily better the higher it is.

[0093] from Figure 1 and Figure 2 It can be seen that the morphology of mineral particles in the simulated lunar soil changed before and after modification. Figure 1 The minerals in the unmodified simulated lunar soil are extremely sharp, similar to blades, and easily damage the roots and other organs; however, after being modified by diatoms, its surface is fully etched, forming a fluffy texture, and no longer poses a threat to the roots.

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

[0095] In summary, the lunar soil improvement method provided by this invention addresses the problems of existing lunar bases being unable to achieve self-sufficiency in food and vegetables, and existing lunar soil improvement methods still being unable to support crop cultivation. It provides a method based on diatoms breaking down lunar soil rocks and minerals, providing organic nutrients, and transforming it into cultivable soil for crops. Specifically, this invention uses a mixture of astronaut excrement (urine) and simulated lunar soil as a diatom culture medium. During its growth, the diatoms break down lunar soil rocks and minerals, providing organic nutrients to create cultivable soil for crops. Furthermore, the diatoms can raise the pH, causing heavy metals to precipitate, thereby reducing the amount of heavy metals entering crops and fruits. Using diluted urine as a culture medium in this invention not only achieves waste regeneration but also allows for rapid diatom reproduction, providing oxygen for air travel and lunar soil bases, reducing carbon dioxide concentration, and making lunar soil an effective plant cultivation substrate. This enables large-scale lunar soil improvement and crop cultivation, ensuring the nutrient supply required for long-term personnel presence and stable operation of lunar soil bases. This invention has the advantages of high efficiency, ease of implementation, low cost, and suitability for large-scale and wide-ranging application.

[0096] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for improving lunar soil, characterized in that, It includes: Diluted urine and simulated lunar soil were mixed at a liquid-to-solid ratio of 1 ml: 2-20 g to obtain a mixture. 10 g of the mixture was added per 1 ml of the mixture. 3 ~10 5 Diatom strains were added at a ratio of 1:1, and the mixture was continuously cultured 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 strains are marine algae and / or brackish water diatoms that have undergone tolerance acclimatization.

3. The method for improving lunar soil according to claim 2, characterized in that, The method for tolerance acclimatization includes mixing urine diluted 5-10 times with diatom culture medium at a first volume ratio, culturing diatoms, and obtaining the corresponding algal species after 5-10 generations of continuous cultivation; then placing the algal species in urine diluted 5-10 times with diatom culture medium at a second volume ratio, culturing for 5-10 generations to obtain the corresponding algal species, and repeating the above process. In the first volume ratio, the volume of urine is smaller than the volume of diatom culture medium. The concentration of urine diluted 5-10 times and the volume ratio of diatom culture medium are gradually increased until no diatom culture medium is used for cultivation. Diatoms that can still grow normally are acclimatized diatoms.

4. The method for improving lunar soil according to claim 3, characterized in that, The volume ratio gradually changed 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 medium.

5. The method for improving lunar soil according to claim 2, characterized in that, The marine algae and / or brackish water diatoms include silicon-rich centroclass and pinnate class diatoms.

6. The method for improving lunar soil according to claim 5, characterized in that, The central class of diatoms includes *Chaetoceros*.

7. The method for improving lunar soil according to claim 5, characterized in that, The feathery diatoms include at least one of rhomboid algae and nautiloid algae.

8. The method for improving lunar soil according to claim 1, characterized in that, The culture temperature is 20~30℃, and the culture time is 60~90 days.

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

10. The method for improving lunar soil according to claim 1, characterized in that, The improved lunar soil contains 0.5-1.4% organic matter and has a heavy metal ion passivation rate of more than 20%.

11. An improved lunar soil, characterized in that, It is prepared using the improved lunar soil method as described in any one of claims 1-10.

12. A method for cultivating crops in lunar soil, characterized in that, Crop seeds are planted in the improved lunar soil as described in claim 11, and the crop seeds germinate in 12 to 30 days.

13. The method for planting crops in lunar soil according to claim 12, characterized in that, The crop seeds include rice seeds.

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