Yield-increasing and nitrogen-preserving agent for transforming hermetia illucens into livestock manure and application thereof

Abstract

The invention discloses a yield-increasing and nitrogen-preserving agent for transforming hermetia illucens into livestock manure and application of the yield-increasing and nitrogen-preserving agent. The invention relates to a matrix additive for transforming hermetia illucens into livestock manure. The matrix additive consists of a component A, a component B and a component C, the component A is calcium sulfate, calcium phosphate or magnesium sulfate; the component B is furfural residue; the component C is zeolite, activated carbon or biochar. According to the method, the loss of nitrogen in the process of converting hermetia illucens into livestock manure can be remarkably reduced, the three selected raw materials have no toxic and inhibition effects on insect bodies, the physicochemical properties of the substrate are improved, the growth of the insect bodies is facilitated, the protein yield of a larva finished product is effectively increased, meanwhile, the fertility level and the nitrogen structure of insect sand residues are improved, and the yield of the larva is increased. The absorption by plants is easy. The use process is simple to operate, small in dosage, high in efficiency and beneficial to popularization.

Description

Technical Field

[0001] The invention relates to the technical field of black soldier flies breeding, and in particular to an additive for increasing the final yield and quality of larvae and reducing ammonia release in the process of black soldier flies degrading livestock and poultry excrement, and an application thereof. Background Art

[0002] The breeding industry relies heavily on the supply of feed, especially the import of protein resources. As the scale of intensive livestock and poultry breeding in my country increases year by year, the cost of traditional feed protein ingredients such as soybean meal gradually increases with market demand, and now accounts for 60%-70% of the total production cost of the breeding industry. The breeding industry is increasingly in need of finding low-cost protein sources to replace traditional feed protein. On the other hand, the livestock and poultry manure produced in the breeding process has caused a large outflow of nutrients in agricultural production. According to statistics, about 15.97 million tons and 3.63 million tons of nitrogen and phosphorus nutrients are lost in the form of manure in the breeding process in China every year, and its overall potential output value can reach more than 150 billion yuan, which undoubtedly increases the gap between supply and demand of feed. Black soldier flies are a low-cost saprophytic insect that can grow using nutrients in livestock and poultry manure. Its insect body is rich in nutrients such as protein and fat, and can be used as a source of feed protein for livestock and aquatic products. The degraded residue (worm sand) can also be used as an organic fertilizer for agricultural production, so it has been widely used. However, in the process of using feces to feed black soldier flies, it was found that the nitrogen loss was quite serious, with the nitrogen loss of the initial substrate reaching more than 30%, which greatly affected the final yield of insect protein. At the same time, the NH3 produced during the conversion process also aggravated air pollution.

[0003] During the biological transformation of black soldier flies, the volatilization of NH3 accounts for more than 70% of the total nitrogen loss. At present, there are generally two ways to inhibit the loss of NH3 during the transformation process at home and abroad: one is to change the process to reduce the production of NH3, such as adding high C / N materials such as sawdust and straw, or adjusting the moisture content of the matrix. The second is to fix the produced NH3 in the matrix by adding exogenous additives to reduce its dissipation loss. Exogenous additives mainly include: ① Metal salt compounds, such as calcium chloride, copper sulfate, magnesium chloride, etc. Among them, SO4 2- , Cl - Can be used with the generated NH4 + Combine to form a stable complex salt, thereby reducing NH3 volatilization. ② Microbial agents, including Bacillus subtilis, yeast, etc., mainly use microorganisms to regulate nitrogen metabolism during composting and intercept nitrogen through nitrogen fixation. ③ High specific surface area adsorbents, such as activated carbon, zeolite, sepiolite, clay, etc., reduce nitrogen loss by adsorbing NH3.

[0004] The current research and application of nitrogen retainers for the biotransformation of livestock and poultry manure by black soldier flies mainly focuses on using single minerals or other substances to reduce nitrogen loss and increase insect protein production. Although simple to operate and easy to use, they have disadvantages such as short duration and poor nitrogen retention effect. In addition, some nitrogen retainer components inhibit the growth of black soldier fly larvae, which is not conducive to insect protein production. More effective methods and approaches are needed to reduce nitrogen loss and gas emissions during the treatment of manure by black soldier flies. Summary of the invention

[0005] The purpose of the present invention is to provide a production-increasing and nitrogen-retaining agent for transforming livestock and poultry manure by black soldier flies and its application. The production-increasing and nitrogen-retaining agent can effectively control the nitrogen loss in the process of biotransformation of livestock and poultry manure, increase the insect body yield and nutritional quality, and effectively improve the plant growth-promoting ability of the finished insect sand product.

[0006] In a first aspect, the present invention provides a substrate additive for transforming livestock manure with black soldier flies, which comprises component A, component B and component C; The component A is calcium sulfate, calcium phosphate or magnesium sulfate; The component B is furfural residue; The component C is zeolite, activated carbon or biochar.

[0007] The above-mentioned matrix additive for converting poultry and livestock feces by black soldier flies is composed of the following components in parts by weight: 10 to 20 parts of component A, 20 to 40 parts of component B and 40 to 60 parts of component C; The particle size of the matrix additive is less than 60 mesh.

[0008] Furthermore, the matrix additive consists of the following components in parts by weight: 10 to 20 parts of component A, 20 to 30 parts of component B and 60 parts of component C.

[0009] As an example, the substrate additive for converting livestock manure by black soldier flies is any one of the following: 1) The matrix additive is composed of the following components in parts by weight: 20 parts of component A, 20 parts of component B and 60 parts of component C; 2) The matrix additive is composed of the following components in parts by weight: 10 parts of component A, 30 parts of component B and 60 parts of component C.

[0010] In a second aspect, the present invention provides the use of the substrate additive for transforming livestock manure by black soldier flies as described in any one of the above items in at least one of the following A1) to A5): A1) Reduce the amount of NH3 released by black soldier flies when converting livestock manure; A2) Reduce the nitrogen loss rate of livestock manure converted by black soldier flies; A3) Reduce the pH value of the substrate in livestock manure that is transformed by black soldier flies; A4) Increase the production of black soldier flies transformed into livestock and poultry manure; A5) Increase the protein content of livestock and poultry feces transformed by black soldier flies.

[0011] In a third aspect, the present invention provides a method for reducing the NH3 release or nitrogen loss rate of black soldier fly conversion of livestock and poultry manure, comprising the following steps: inoculating black soldier fly larvae into a matrix mixed with any of the additives described above, breeding black soldier flies, and collecting insect bodies and insect sand after breeding; the matrix contains livestock and poultry manure.

[0012] In the above method for reducing the NH3 release or nitrogen loss rate of livestock manure converted by black soldier flies, 10 to 50 kg of the additive is added to every 1 t of the substrate, such as adding 10 kg of the additive (1%) to every 1 t of the substrate; On a dry basis, the matrix is ​​composed of livestock manure, plant waste and livestock carcasses in a mass ratio of (2.5-13): (1.5-6): 1; as an example, on a dry basis, the matrix is ​​composed of livestock manure, plant waste and livestock carcasses in a mass ratio of 7:2:1, 5:3:2, 6.5:3:0.5 or 5:4:1; the livestock manure is preferably chicken manure (such as fresh laying hen manure); the plant waste is preferably fruit and vegetable waste (such as on a dry basis, the fruit and vegetable waste includes 15% beans, 55% cabbage, 10% spinach, 20% pears, and the residue includes fruit cores, vegetable stems, roots, and bean tendon parts); the livestock carcasses are preferably chicken carcasses (such as fresh laying hen carcasses). Further, the plant waste and livestock carcasses are crushed before adding, such as a coarseness of 3 cm. The nitrogen loss rate is the cumulative nitrogen loss of the substrate, and the calculation formula is as follows: nitrogen loss rate (%) = (initial nitrogen content of the substrate - total nitrogen content of the insect body - total nitrogen content of the residue) / initial nitrogen content of the substrate.

[0013] In a fourth aspect, the method of the present invention for increasing the insect body yield or insect body protein content of black soldier flies converted into poultry and livestock feces comprises the following steps: inoculating black soldier fly larvae into a matrix mixed with any of the additives described above, breeding black soldier flies, and collecting the insect bodies and insect sand after the breeding is completed; the matrix comprises poultry and livestock feces.

[0014] In the above method for increasing the black soldier fly transformation of poultry and livestock feces worm body yield or worm body protein content, 10 to 50 kg of the additive is added to every 1 t of the substrate, such as adding 10 kg of the additive (1%) to every 1 t of the substrate; On a dry basis, the matrix is ​​composed of livestock manure, plant waste and livestock carcasses in a mass ratio of (2.5-13): (1.5-6): 1; as an example, on a dry basis, the matrix is ​​composed of livestock manure, plant waste and livestock carcasses in a mass ratio of 7:2:1, 5:3:2, 6.5:3:0.5 or 5:4:1. The livestock manure is preferably chicken manure (such as fresh laying hen manure); the plant waste is preferably fruit and vegetable waste (such as on a dry basis, the fruit and vegetable waste includes 15% beans, 55% cabbage, 10% spinach, 20% pears, and the residue includes fruit cores, vegetable stems, roots, and bean tendon parts); the livestock carcasses are preferably chicken carcasses (such as fresh laying hen carcasses). Further, the plant waste and livestock carcasses are crushed before adding, such as a coarseness of 3 cm.

[0015] In a fifth aspect, the present invention provides a method for promoting plant growth, comprising the following steps: S1, inoculating black soldier fly larvae into a matrix mixed with any one of the additives described above, breeding black soldier flies, and collecting insect bodies and insect sand after breeding; the matrix comprises poultry and livestock feces; S2. Add the insect sand into the base soil to cultivate plants.

[0016] In the above method for promoting plant growth, in step S1, 10 to 50 kg of the additive is added to every 1 t of the substrate, such as 10 kg of the additive (1%) is added to every 1 t of the substrate; In step S1, the matrix is ​​composed of livestock manure, plant waste and livestock carcasses in a mass ratio of (2.5-13): (1.5-6): 1 on a dry basis; as an example, the matrix is ​​composed of livestock manure, plant waste and livestock carcasses in a mass ratio of 7:2:1, 5:3:2, 6.5:3:0.5 or 5:4:1 on a dry basis; the livestock manure is preferably chicken manure (such as fresh laying hen manure); the plant waste is preferably fruit and vegetable waste (for example, on a dry basis, the fruit and vegetable waste includes 15% beans, 55% cabbage, 10% spinach, 20% pears, and the residue includes fruit cores, vegetable stems, roots, and bean tendon parts); the livestock carcasses are preferably chicken carcasses (such as fresh laying hen carcasses); In step S2, the insect sand is added in an equal amount of nitrogen, and 200-300 mg of N is added to every 1 kg of dry soil, such as 200 mg / kg, 250 mg / kg, and 300 mg / kg.

[0017] In the above method for promoting plant growth, the plant is a leafy vegetable, preferably lettuce (such as head lettuce), Chinese cabbage or spinach; The promotion of plant growth is reflected in increasing plant yield, such as the fresh weight of aboveground parts.

[0018] In any of the above uses and methods, the black soldier fly larvae are several-day-old black soldier fly larvae; as an example, the black soldier fly larvae are 6-day-old black soldier fly larvae.

[0019] In any of the above applications and methods, before the inoculation step, the moisture content of the substrate mixed with the additive is controlled to be between 65% and 75%, such as 70% to 75%.

[0020] In any of the above uses and methods, as an example, 500 g of black soldier fly larvae are inoculated per substrate with a volume of 100*100*20 cm and cultured in an open environment at ambient temperature and humidity; the substrate is laid flat and has a thickness of no more than 20 cm.

[0021] In any of the above applications and methods, the reaction principle is: during the biological transformation of black soldier flies, most of the NH3 volatilization occurs in the first 6-8 days. Taking nitrogen conservation measures during this period, especially in-situ nitrogen conservation measures, is the key to reducing the loss of nitrogen in the matrix. Zeolite has a high porosity and specific surface area, which can adsorb NH3 and retain it in the matrix. It can also increase the porosity inside the pile and shorten the anaerobic time inside the matrix to improve the activity of insects and microorganisms; SO4 in CaSO4 2- Can react with NH4 + Combine to form a stable complex salt that remains inside the matrix. The reaction equation is as follows: 2NH4 + +SO4 2- +CaSO4+H2O→(NH4)2SO4·CaSO4·H2O.

[0022] The pH value suitable for the growth of nitrogen-retaining microorganisms is between 5.5 and 8.5. Too high a pH value is not conducive to the growth of microorganisms and will aggravate the release of NH3. The calcium sulfate added to the yield-increasing nitrogen-retaining agent of the present invention is weakly acidic, and the special porous structure of zeolite and the easily degradable small molecular organic matter of furfural residue can provide a suitable environment for the microbial community, increase the abundance of the flora, and help improve the in-situ nitrogen fixation ability of indigenous microorganisms.

[0023] The present invention has the following beneficial effects: (1) In the yield-increasing and nitrogen-retaining agent of the present invention, furfural residue is combined with zeolite (zeolite can be replaced by activated carbon or biochar), which can enhance the nutrient concentration and aeration environment of the substrate, increase the initial expansion rate of indigenous microorganisms, and significantly enhance the in-situ nitrogen fixation ability of microorganisms. The weak acidic nature of calcium sulfate (calcium sulfate can be replaced by calcium phosphate or magnesium sulfate) slows down the increase in pH during the conversion process, which leads to the inhibition of the activity of nitrogen-fixing microorganisms and the release of a large amount of NH3. Compared with traditional bacterial agents or single mineral additives, the treatment effect of the present invention is stable, there is no need to worry about the occurrence of microbial antagonism, and the nitrogen retention effect is more comprehensive and lasts longer.

[0024] (2) Use mechanical crushing to pre-treat materials such as fruits and vegetables, livestock and poultry carcasses and pass them through a 60-mesh sieve. This can break up the aggregation of indigestible materials such as bones and fibers, making them easier to mix evenly, thereby reducing the difficulty of black soldier flies ingesting them and promoting complete digestion of the substrate.

[0025] (3) The addition of livestock and poultry carcasses to the matrix of the present invention can increase larval yield, crude protein content, survival rate, bioconversion rate and waste reduction rate. This is because the visceral part of livestock and poultry carcasses is rich in active amino acids, and the intestinal microorganisms in the body can also produce proteolytic enzymes, which can hydrolyze the macromolecular proteins in the substrate into amino acids, which is beneficial to the growth of the insect body and protein accumulation. After experimental verification, the larval yield and protein of the matrix of the present invention and the matrix of pure chicken manure and chicken manure + vegetable waste were increased by 35.75% to 37.03% and 14.52% to 19.25%, respectively, both reaching the significant level. At the same time, this insect sand can also significantly increase the plant yield by more than 11.45% after being applied to the soil, and improve the plant quality. The addition of fruit and vegetable waste to the matrix of the present invention can increase the proportion of small molecular carbon sources in the matrix during the conversion process, improve the carbon-nitrogen ratio of the easily decomposable part, reduce the production of NH3, and further reduce its pollution to the environment while realizing efficient resource utilization of feces. The matrix of the present invention combines livestock and poultry excrement, livestock and poultry carcasses and fruit and vegetable waste to feed black soldier fly larvae. Compared with a single matrix, it can better promote the decomposition of macromolecular nutrients in the substrate, improve the absorption efficiency and bioconversion rate of the insect body, and at the same time significantly improve the biological activity and larval survival ratio, enhance the in-situ utilization capacity of nutrients, and reduce nitrogen loss.

[0026] (4) The matrix additive of the present invention can significantly reduce the loss of nitrogen in the process of converting livestock manure into black soldier flies. The three selected raw materials have no toxic inhibitory effect on the insect body, and improve the physical and chemical properties of the matrix, which is beneficial to the growth of the insect body, effectively increasing the protein yield of the larval product, and at the same time improving the fertility level and nitrogen structure of the insect sand residue, which is easy to be absorbed by plants. The use process is simple to operate, the dosage is small, the efficiency is high, and it is conducive to promotion. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It shows the NH3 release of black soldier flies fed with chicken manure containing the yield-increasing nitrogen-retaining agent in Example 2 of the present invention and without the addition of the nitrogen-retaining agent.

[0028] Figure 2 It shows the pH value of the chicken manure fed to black soldier flies with the production increasing nitrogen retaining agent in Example 2 of the present invention and without the addition of the nitrogen retaining agent.

[0029] Figure 3 It shows the comparison of the insect body yield of black soldier flies fed with chicken manure containing the yield-increasing nitrogen-retaining agent in Example 2 of the present invention and that without adding the nitrogen-retaining agent.

[0030] Figure 4It shows the comparison of the protein content of black soldier flies fed with chicken manure containing the yield-increasing nitrogen-retaining agent in Example 2 of the present invention and that without the addition of the nitrogen-retaining agent.

[0031] Figure 5 It shows the nitrogen loss rate of black soldier flies fed with chicken manure containing the yield-increasing nitrogen-retaining agent in Example 2 of the present invention and without adding the nitrogen-retaining agent.

[0032] Figure 6 It shows the crop yield after applying the insect sand produced by the yield-increasing nitrogen-retaining agent in Example 4 of the present invention to the soil with that produced without adding the nitrogen-retaining agent.

[0033] Note: Figure 3-Figure 6 In the table, * indicates a significant level of P < 0.05; ** indicates a significant level of P < 0.01. DETAILED DESCRIPTION

[0034] The present invention is further described in detail below in conjunction with specific embodiments, and the examples provided are only for illustrating the present invention, rather than for limiting the scope of the present invention. The examples provided below can be used as a guide for further improvements by those of ordinary skill in the art, and do not constitute a limitation of the present invention in any way.

[0035] The methods used in the following examples, unless otherwise specified, are all conventional methods, carried out according to the techniques or conditions described in the literature in the art or according to the product instructions. The materials, reagents, etc. used in the following examples, unless otherwise specified, can all be obtained from commercial sources.

[0036] In the following examples, calcium sulfate and zeolite were purchased from Shuangying Chemical Co., Ltd., and the CAS number of calcium sulfate is 10101-41-4; furfural residue was provided by Youyuan Bio-Organic Fertilizer Co., Ltd. in Quzhou County, which is the residue of corn cob acid hydrolysis at 100°C.

[0037] The livestock and poultry carcasses in the following embodiments are dead laying hens from the local laying hen farm of Beijing Agricultural University in Quzhou County. The time of death was the same day, and the breed was Nongjin No. 1 bred by the company.

[0038] The fruit and vegetable waste in the following embodiments is fruit and vegetable waste, including 15% beans, 55% cabbage, 10% spinach, and 20% pears, the proportions are dry basis, and the residues include fruit cores, vegetable stems, roots, and bean tendon parts.

[0039] Example 1 This example compares the effects of adding a composite matrix composed of livestock and poultry manure and livestock and poultry carcasses with a livestock and poultry manure matrix on black soldier fly farming, including black soldier fly larvae weight, black soldier fly larvae yield, crude protein content, survival rate, bioconversion rate and waste reduction rate.

[0040] 1. Matrix Combination The raw materials in this embodiment are as follows: fresh laying hen feces (water content <80%) and dead laying hen carcasses.

[0041] The above raw materials are mechanically crushed to a particle size of ≤3 cm for later use.

[0042] 2. Hatching larvae The purchased eggs were incubated at 30°C and 30% relative humidity, and then transferred to coarse wheat bran and cultured in the dark until they were 6 days old.

[0043] 3. Raw material loading Fresh laying hen feces and dead laying hen carcasses were mixed evenly in a mass ratio of 9:1, the moisture content was controlled to 75%, and the mixture was spread evenly in a square culture box (21cm*19cm*9.5cm) with a height of 5cm. Chicken manure without laying hen carcasses was used as a control.

[0044] 4. Larvae inoculation and index determination 4 g of 6-day-old black soldier fly larvae were added to each box. The compost was turned regularly and a small amount of water was added in the early stage of transformation to maintain a constant moisture content. During the transformation period, the average weight of the insects was collected and recorded on days 0, 2, 4, 6, 8, 10, 12, and 14. After 14 days, the reaction was completed, and the residue (worm sand) was collected and the bioconversion rate, waste reduction, and larval survival rate were calculated, and the protein content of the insects was determined. The calculation was based on the following formula: bioconversion rate (%) = larval dry weight / substrate dry weight × 100%; waste reduction rate (%) = (initial mass of substrate - residue mass) / initial mass of substrate × 100%.

[0045] The changes in the weight of black soldier fly larvae during the transformation process are shown in Table 1. Compared with the control group, the addition of laying hen carcasses significantly increased the weight gain rate of black soldier fly larvae, with prepupae appearing 2 days earlier and the final average weight increase of 18.11%.

[0046]

[0047] The results of the production, crude protein content, survival rate, bioconversion rate and waste reduction rate of black soldier fly larvae are shown in Table 2. Compared with the control group, the addition of dead chickens to the substrate significantly increased the larval production by 29.15%, the crude protein content by 11.45%, the survival rate by 11.92%, and the bioconversion rate and waste reduction rate by 11.54% and 24.23%, respectively.

[0048]

[0049] Example 2 The present embodiment provides a production-increasing and nitrogen-retaining agent and its application in increasing and retaining nitrogen by reducing the production of black soldier flies when feeding chicken manure.

[0050] 1. Yield-increasing and nitrogen-retaining agent The composition of the yield-increasing and nitrogen-retaining agent in this embodiment is as follows: 200 g of calcium sulfate, 200 g of furfural residue, and 600 g of zeolite.

[0051] The raw materials are mixed in the above parts by mass, crushed mechanically and passed through a 60-mesh sieve to obtain the obtained product.

[0052] 2. Black soldier flies transform livestock manure The specific steps are as follows: (1) Raw material pretreatment: Mechanically crush the complete carcasses of dead livestock and poultry and fruit and vegetable waste to a fineness of 3 cm and set aside after processing.

[0053] (2) Hatching larvae: Incubate purchased eggs at 30°C and 30% relative humidity, transfer to coarse wheat bran and culture in the dark until they are 6 days old.

[0054] (3) Raw material mixing: fresh chicken manure, fruit and vegetable waste and livestock carcasses are mixed evenly in a mass ratio of 7:2:1, nitrogen retainer is added at a ratio of 1wt% of the matrix, and the moisture content is controlled at 70%-75%. Spread on a 1m 2 The same substrate without nitrogen retaining agent was used as the control group.

[0055] (4) Larvae inoculation and index determination: Add 500 g of 6-day-old black soldier fly larvae (substrate volume is 100*100*20 cm), culture in an open environment, turn the compost regularly and add a small amount of water in the early stage of transformation to maintain a constant moisture content. During the transformation period, collect and measure the NH3 concentration on days 0, 2, 4, 6, 8, 10, 12, and 14, and test the pH value of the substrate. After 14 days, the reaction is completed, and the total nitrogen content of the residue (worm sand) is collected and determined. The black soldier fly bodies are sieved and weighed, and the average protein content of the bodies is determined. Calculate according to nitrogen loss rate (%) = (initial nitrogen content of the substrate - total nitrogen content of the body - total nitrogen content of the residue) / initial nitrogen content of the substrate. The method for determining the NH3 concentration is as follows: During the measurement of NH3, a dynamic box is inserted into the matrix, and the height of the exposed space inside the box is kept consistent (10 cm). An air pump is used to evacuate the air for 10 minutes. Ammonia gas is collected by continuous absorption method, and 30 ml of 2% boric acid solution is used as the absorption liquid. After the end, 2-3 drops of methyl red and bromocresol green indicators are added, and then 1% sulfuric acid is used to titrate until color changes, and the volume of sulfuric acid consumed is recorded.

[0056] Figure 1 The results show that the NH3 emission peak of the black soldier fly treated with the nitrogen-increasing agent of the present invention was reduced by 30.03% compared with the control group without any conditioner (the highest peak of ammonia emission was on the 10th day and the 8th day, respectively).

[0057] Figure 2The results show that the pH value of the final substrate of the black soldier fly manure treated with the nitrogen-increasing agent of the present invention was reduced by 6.04% (14th day of conversion) compared with the control group without any conditioner.

[0058] Figure 3 The results show that the total insect yield of the black soldier fly fed with the nitrogen-increasing agent of the present invention is 17.47% higher than that of the control group without any conditioner.

[0059] Figure 4 The results show that the protein content of the black soldier flies fed with the nitrogen-increasing agent of the present invention is compared with that of the chicken manure without nitrogen-increasing agent. The results show that the protein content of the black soldier flies fed with the nitrogen-increasing agent of the present invention is increased by 15.07% compared with the control group without any conditioner.

[0060] Figure 5 The nitrogen loss rate of the black soldier flies fed with the nitrogen-increasing agent of the present invention is compared with that of the chicken manure without the nitrogen-increasing agent. Compared with the control group without any conditioner, the cumulative nitrogen loss ratio of the substrate was reduced by 44.42%.

[0061] Example 3 The present embodiment provides a production-increasing and nitrogen-retaining agent and its application in increasing and retaining nitrogen by reducing the production of black soldier flies when feeding chicken manure.

[0062] 1. Yield-increasing and nitrogen-retaining agent The composition of the yield-increasing and nitrogen-retaining agent in this embodiment is as follows: 100 g of calcium sulfate, 300 g of furfural residue, and 600 g of zeolite.

[0063] The raw materials are mixed in the above parts by mass, crushed mechanically and passed through a 60-mesh sieve to obtain the obtained product.

[0064] 2. Black soldier flies transform livestock manure The specific steps are as follows: (1) Raw material pretreatment: Mechanically crush the complete carcasses of dead livestock and poultry and fruit and vegetable waste to a fineness of 3 cm and set aside after processing.

[0065] (2) Hatching larvae: Incubate purchased eggs at 30°C and 30% relative humidity, transfer to coarse wheat bran and culture in the dark until they are 6 days old.

[0066] (3) Raw material mixing: fresh chicken manure, fruit and vegetable waste and livestock carcasses are mixed evenly in a mass ratio of 7:2:1, nitrogen retainer is added at a ratio of 1wt% of the matrix, and the moisture content is controlled at 70%-75%. Spread on a 1m 2The same substrate without nitrogen retaining agent was used as the control group.

[0067] (4) Larvae inoculation and index determination: Add 500 g of 6-day-old black soldier fly larvae (substrate volume is 100*100*20 cm), culture in an open environment, turn the compost regularly and add a small amount of water in the early stage of transformation to maintain a constant moisture content. During the transformation period, collect and measure the NH3 concentration on the 0th, 2nd, 4th, 6th, 8th, 10th, 12th and 14th days, and detect the pH value of the substrate. After 14 days, the reaction is completed, and the total nitrogen content of the residue (worm sand) is collected and measured. The black soldier fly bodies are sieved and weighed, and the average protein content of the bodies is determined. Calculate according to nitrogen loss rate (%) = (initial nitrogen content of the substrate - total nitrogen content of the body - total nitrogen content of the residue) / initial nitrogen content of the substrate. The method for determining NH3 concentration is the same as in Example 2.

[0068] The NH3 emission rate and substrate nitrogen loss during the transformation process of black soldier flies are shown in Table 3. The results showed that the peak NH3 emission rate of the treatment with the addition of the yield-increasing and nitrogen-retaining agent was significantly reduced by 23.91% compared with the control group, and the peak appeared 2 days earlier, and the final nitrogen loss rate was reduced by 38.07%.

[0069]

[0070] The change of substrate pH value during the conversion process is shown in Table 4. The results show that the pH value of the final substrate is reduced by 6.98% when the black soldier fly livestock manure treatment with the yield increasing and nitrogen retaining agent of the present invention is compared with the control group without any conditioner.

[0071]

[0072] The changes in insect yield and insect protein content are shown in Table 5. The results show that the black soldier fly livestock manure treatment with the yield-increasing and nitrogen-retaining agent of the present invention increased the final total insect yield by 20.12% and the protein content of the insect by 11.89% compared with the control group without any conditioner.

[0073]

[0074] Example 4 This embodiment provides a method for promoting plant growth using the insect sand obtained in Example 1.

[0075] The composition of the insect sand in the verification test: the residue of the CK group in Example 1, and the residue of the yield-increasing and nitrogen-retaining agent group in Example 1.

[0076] The specific steps are as follows: (1) Soil pretreatment: Take some soil from the top 20 cm of cultivated land, pass it through a 4-mesh metal sieve, dry it thoroughly and mix it for later use.

[0077] (2) Potted plant experiment: Take two 4 L flower pots, fill each with 5 kg of base soil, add two groups of insect sand at a ratio of 300 mg N / kg soil and mix well, inoculate 30 cabbage lettuce seeds that have been germinated for 24 hours, water thoroughly, and seedling to 1 plant / pot within 15 days. After 90 days of growth, harvest the plants, weigh and record the fresh weight of the aboveground part of each pot.

[0078] Figure 6 The results show that the crop yield after applying the insect sand produced by the yield-increasing and nitrogen-retaining agent of the present invention to the soil is compared with that of the control group without any conditioner. The results show that the weight of the single plant of lettuce produced after the insect sand was applied to the soil with the black soldier fly livestock manure treatment added with the yield-increasing and nitrogen-retaining agent of the present invention increased by 25.31% compared with the control group without any conditioner.

[0079] The above examples show that the yield-increasing and nitrogen-retaining agent of the present invention can effectively control the nitrogen loss in the process of biotransformation of poultry and livestock manure, increase the insect yield and nutritional quality, and effectively improve the plant growth-promoting ability of the finished insect sand product.

[0080] The present invention has been described in detail above. For those skilled in the art, without departing from the purpose and scope of the present invention, can implement the present invention in a wider range under equivalent parameters, concentrations and conditions. Although the present invention provides specific embodiments, it should be understood that the present invention can be further improved. In a word, according to the principle of the present invention, the application is intended to include any changes, uses or improvements to the present invention, including departing from the disclosed scope in the application and the changes made with conventional techniques known in the art.

Claims

1. A substrate additive for transforming livestock manure by black soldier flies, characterized in that: It consists of component A, component B and component C; The component A is calcium sulfate, calcium phosphate or magnesium sulfate; The component B is furfural residue; The component C is zeolite, activated carbon or biochar.

2. The substrate additive for transforming livestock excrement by black soldier flies according to claim 1, characterized in that: In parts by weight, the matrix additive consists of the following components: 10 to 20 parts of component A, 20 to 40 parts of component B and 40 to 60 parts of component C; and / or, The particle size of the matrix additive is less than 60 mesh.

3. Use of the substrate additive for transforming livestock manure by black soldier flies according to any one of claims 1 to 2 in at least one of the following A1) to A5): A1) Reduce the amount of NH3 released by black soldier flies when converting livestock manure; A2) Reduce the nitrogen loss rate of livestock manure converted by black soldier flies; A3) Reduce the pH value of the substrate in livestock manure that is transformed by black soldier flies; A4) Increase the production of black soldier flies transformed into livestock and poultry manure; A5) Increase the protein content of livestock and poultry feces transformed by black soldier flies.

4. A method for reducing the NH3 release or nitrogen loss rate of livestock manure converted by black soldier flies, characterized in that: The method comprises the following steps: inoculating black soldier fly larvae into a matrix mixed with the additives described in any one of claims 1 to 2, breeding black soldier flies, and collecting insect bodies and insect sand after breeding; the matrix comprises poultry and livestock excrement.

5. The method for reducing the NH3 release or nitrogen loss rate of livestock manure converted by black soldier flies according to claim 4, characterized in that: Adding 10 to 50 kg of the additive per 1 t of the substrate; and / or, On a dry basis, the matrix is ​​composed of livestock and poultry manure, plant waste and livestock and poultry carcasses in a mass ratio of (2.5-13):(1.5-6):1; the livestock and poultry manure is preferably chicken manure; the plant waste is preferably fruit and vegetable waste; and the livestock and poultry carcasses are preferably chicken carcasses.

6. A method for increasing the yield of black soldier flies transformed into poultry and livestock feces or the content of insect protein, characterized in that: The method comprises the following steps: inoculating black soldier fly larvae into a matrix mixed with the additives described in any one of claims 1 to 2, breeding black soldier flies, and collecting insect bodies and insect sand after breeding; the matrix comprises poultry and livestock excrement.

7. The method for increasing the yield of black soldier flies transformed into livestock and poultry feces or the content of their protein according to claim 6, characterized in that: Adding 10 to 50 kg of the additive per 1 t of the substrate; and / or, On a dry basis, the matrix is ​​composed of livestock and poultry manure, plant waste and livestock and poultry carcasses in a mass ratio of (2.5-13):(1.5-6):1; the livestock and poultry manure is preferably chicken manure; the plant waste is preferably fruit and vegetable waste; and the livestock and poultry carcasses are preferably chicken carcasses.

8. A method for promoting plant growth, characterized in that: The steps include: S1. Inoculating black soldier fly larvae into a matrix mixed with the additive according to any one of claims 1 to 2 to culture black soldier flies, and collecting insect bodies and insect sand after the culture is completed; the matrix comprises poultry and livestock feces; S2. Add the insect sand into the base soil to cultivate plants.

9. The method for promoting plant growth according to claim 8, characterized in that: In step S1, 10 to 50 kg of the additive is added to every 1 t of the substrate; and / or, In step S1, the matrix is ​​composed of livestock manure, plant waste and livestock carcasses in a mass ratio of (2.5-13): (1.5-6): 1 on a dry basis; the livestock manure is preferably chicken manure; the plant waste is preferably fruit and vegetable waste; and the livestock carcasses are preferably chicken carcasses; In step S2, the insect sand is added in an equal amount of nitrogen, and the insect sand containing 200 to 300 mg N is added to every 1 kg of dry soil.

10. The method for promoting plant growth according to any one of claims 8-9, characterized in that: The plant is a leafy vegetable, preferably lettuce, Chinese cabbage or spinach; The promoting of plant growth is reflected in increasing plant yield.

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