CN110803965A

CN110803965A - Organic fertilizer with coffee grounds as main raw materials, aerobic composting process and application thereof

Info

Publication number: CN110803965A
Application number: CN201911113344.2A
Authority: CN
Inventors: 崔荣; 路昌; 张昱; 王虔祖
Original assignee: Yantai University
Current assignee: Yantai University
Priority date: 2019-11-14
Filing date: 2019-11-14
Publication date: 2020-02-18

Abstract

The invention belongs to the technical field of resource utilization and composting, and relates to an organic fertilizer with coffee grounds as a main raw material, an aerobic composting process and application thereof. The invention takes the residual coffee grounds processed by the coffee shop as the main raw material, reduces the environmental pollution caused by the coffee grounds and enables the coffee grounds to be recycled. The high-temperature aerobic composting fermentation is realized by controlling the using amount and the water content of each component in the mixed material and controlling the ventilation and the ventilation amount according to the oxygen content in the reactor and the temperature of a compost, the fermentation period is shortened, the energy consumption of the composting is reduced, the decomposition degree of the product is improved, and the degradation rate of organic matters is up to more than 40%. Because the coffee grounds have special porous structures and have adsorption effect on soluble salts in the composting process, the invention ensures smaller EC variation range, reduces the salinization risk of composting products and has good repairing effect on soil. The pH value of the organic fertilizer prepared by the invention is 6.69-7.06, and the organic fertilizer meets the requirement that the pH value of a compost product is 5.5-8.5.

Description

Organic fertilizer with coffee grounds as main raw materials, aerobic composting process and application thereof

Technical Field

The invention belongs to the technical field of resource utilization and composting, and particularly relates to an organic fertilizer with coffee grounds as a main raw material, an aerobic composting process and application thereof.

Background

In recent years, coffee consumption has become a popular trend, statistically, reaching 968.286 ten thousand tons in 2017/2018 years globally. While the coffee industry is developing at a high rate, the byproduct coffee grounds from coffee production pose a significant environmental burden. A plurality of resource utilization schemes of coffee grounds exist, such as extraction of specific compounds such as mannose and antioxidant polyphenol, but a large amount of wastes still exist after extraction, and the environmental burden still exists. The coffee grounds are rich in organic matters, but have biotoxicity, and are not beneficial to direct utilization of agricultural production.

The composting technology can convert complex organic matters into stable humus, can eliminate biological toxicity and realize the cyclic utilization of resources, and meets the requirements of sustainable development.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides an organic fertilizer taking coffee grounds as a main raw material, an aerobic composting process and application thereof.

The technical scheme for solving the technical problems is as follows:

an organic fertilizer taking coffee grounds as a main raw material comprises the following raw material components in percentage by weight: 80-90% of coffee grounds, 1-2% of a blending agent A and 8-13% of a blending agent B, wherein the raw materials are dry weights.

Further, the blending agent A is a nitrogen-containing substance; the blending agent B is rice husk or wood dust.

Further, the nitrogen-containing substance is urea.

The second purpose of the invention is to provide an aerobic composting process of the organic fertilizer taking coffee grounds as the main raw material, which comprises the following steps:

(1) preparing materials: mixing the coffee grounds, the blending agent A and the blending agent B according to the formula proportion, and adding water to ensure that the water content of the mixed material is 52-58% and the carbon-nitrogen ratio is 23-27 to obtain a premixed material;

(2) composting: putting the premixed material obtained in the step (1) into an adiabatic composting reactor, adding a high-temperature aerobic composting microbial inoculum which is 1 percent of the weight of the premixed material obtained in the step (1) for composting, performing aerobic composting fermentation, raising the central temperature of a compost to 55-63 ℃, and keeping for 5-7 days to finish primary fermentation;

when the central temperature of the pile is reduced to 20-25 ℃ from 55-63 ℃, completing secondary fermentation, and decomposing the compost to obtain an organic fertilizer;

wherein, in the processes of primary fermentation and secondary fermentation, the ventilation and air volume are controlled according to the oxygen content in the reactor and the temperature of the reactor, and the reactor is turned once every 4 days after turning the reactor on the first day.

Furthermore, the ventilation and the ventilation quantity are controlled at any time according to the change of the oxygen demand in the compost, and the ventilation quantity is controlled to be 0.4-0.5L (min kg)^-1) The ventilation control is automatically performed in the following manner:

the beneficial effect of adopting the further scheme is that the oxygen supply amount is ensured, the oxygen supply energy consumption can be greatly reduced, the temperature of the compost body is controlled, and the composting period is shortened.

Further, the period of the composting is 15 days.

Furthermore, the change range of the conductivity EC value of the premixed material is 0.854-1.157mS cm in the composting process^-1(ii) a The electric conductivity EC value of the obtained organic fertilizer is 0.845-0.877mS cm^-1。

Further, the pH value of the obtained organic fertilizer is 6.92-7.06; the seed germination index GI of the obtained organic fertilizer reaches more than 85 percent.

The third purpose of the invention is to provide the application of the organic fertilizer taking coffee grounds as the main raw material as a base fertilizer in the field of planting of the potted ornamental plants of lily.

The fourth purpose of the invention is to provide the application of the organic fertilizer taking coffee grounds as the main raw material in the field of plant insect expelling as an additional fertilizer.

The invention has the beneficial effects that:

the invention takes the residual coffee grounds processed by the coffee shop as the main raw material, reduces the environmental pollution caused by the coffee grounds and enables the coffee grounds to be recycled. The high-temperature aerobic composting fermentation is realized by controlling the using amount and the water content of each component in the mixed material and controlling the ventilation and the ventilation amount according to the oxygen content in the reactor and the temperature of a compost, the fermentation period is shortened, the energy consumption of the composting is reduced, the decomposition degree of the product is improved, and the degradation rate of organic matters is up to more than 40%. Because the coffee grounds have special porous structures and have adsorption effect on soluble salts in the composting process, the invention ensures smaller EC variation range, reduces the salinization risk of composting products and has good repairing effect on soil. The pH value of the organic fertilizer prepared by the invention is 6.69-7.06, and the organic fertilizer meets the requirement that the pH value of a compost product is 5.5-8.5.

Drawings

FIG. 1 is a graph showing the relationship between the temperature of the center of compost and the fermentation time;

FIG. 2 is a graph showing the relationship between the pH of compost and fermentation time;

FIG. 3 is a graph showing the EC values of compost versus fermentation time;

FIG. 4 is a schematic graph showing TN value of compost versus fermentation time;

FIG. 5 is a graph showing the GI value of compost versus fermentation time.

Detailed Description

The principles and features of this invention are described below in conjunction with examples, which are set forth to illustrate, but are not to be construed to limit the scope of the invention.

[ Experimental design ]

The invention selects L₉(3⁴) The multi-index orthogonal experimental scheme takes the degradation rate of organic matters in the compost materials as an evaluation index. On the basis of the preliminary experiments in the previous period, the factors and levels of the orthogonal experiments are determined as shown in table 1.

TABLE 1 orthogonal test factors and levels

And (3) carrying out orthogonal experiments on 9 groups simultaneously, wherein 2kg of air-dried coffee grounds are taken in each group, and water, urea and glucose are added to adjust the materials to the corresponding water content and carbon-nitrogen ratio. The rice hulls as the leavening agent need to be adjusted to have the same water content as the materials in the group of reactors before the materials are charged, so that the influence of the water absorption of the rice hulls on the water content of the materials is reduced.

1. Sample collection and analysis

The core temperature of each reactor was measured 12 hours a day during the experiment and the ambient temperature was recorded. The sampling time interval is 4 days, namely 1 st, 5 th, 9 th, 13 th, 17 th and 21 th days, turning over and sampling, and quartering. The sample is divided into two parts, one part is used for preparing a leaching solution, and the other part is naturally air-dried and sieved by a 0.149mm sieve to be detected.

Preparing a leaching solution: taking 10g of fresh sample, adding 100mL of deionized water, and carrying out 200 r.min^-1Shaking and leaching for 30min, 5000 r.min^-1Centrifugation was performed for 5min, and the supernatant was taken for determination of pH and conductivity (EC).

Total Organic Carbon (TOC) was measured by potassium dichromate volumetric method, and Total nitrogen (Totalnitrogen, TN) was measured by Kjeldahl method.

Determination of Germination Index (GI) of seeds: and (3) putting 5mL of the leaching solution in a culture dish paved with filter paper, uniformly placing 20 rape (Shanghai green) seeds in the dish, culturing for 48h in a constant-temperature incubator at 25 ℃, taking deionized water as a blank control, and measuring the germination rate and the root length of the seeds, namely calculating the germination index of the seeds by the following formula.

2. Results and analysis of the experiments

2.1 analysis of orthogonal test results

The organic matter degradation rate in the composting process is an important index for representing the composting degree, so that the organic matter degradation rate is selected as an important reference for the orthogonal test. The orthogonal experiment design can be visually analyzed through range calculation to represent the influence degree of each level in each factor on the experiment result, the degradation rate of the compost organic matter is selected as a parameter in the experiment to carry out range analysis, and the optimal process combination of the orthogonal experiment is determined. The range analysis of the orthogonal test is shown in Table 2.

TABLE 2 range analysis of orthogonal experiments

As can be seen from Table 2, the degradation effect of the organic matter treated by No. 6 is the best, and the degradation rate reaches 45.18%. Comparing different levels of k values in all factors, the larger the k value is, the best degradation effect of the composting organic matter under the condition is shown, namely, the ventilation quantity is 0.45[ L (min. kg DM)^-1]The water content is 55 percent, the carbon nitrogen ratio is 25 percent, and 9 percent (dry weight ratio) of the leavening agent is added as the optimal process condition, which is consistent with the process condition of No. 6 treatment. According to the range analysis result, the influence degree of each factor on the degradation effect of the organic matters of the compost is as follows: air volume more than carbon-nitrogen ratio more than water content more than leavening agent addition amount.

2.2 variation of compost temperature under different Process parameters

The temperature change of the compost reflects the strength of the life activities of the microorganisms of the compost and the process of organic material conversion, and is also one of indexes for measuring the composting quality and evaluating the composting degree. As shown in FIG. 1, the processing temperatures have basically the same trend and are all subjected to three stages of temperature rise, temperature rise and temperature drop. In the initial composting stage, microorganisms decompose simple organic matters to release a large amount of heat, the temperature of a compost rises, and the temperature rises to a high temperature period (more than 55 ℃) after No. 1, No. 3 and No. 6 treatment for 2d, wherein the temperature rises fastest in No. 6 treatment. The high temperature stage is the key stage of the oxidative decomposition of organic matters in the composting process and is the visual expression of the quality of the composting process conditions. The time for maintaining the high temperature period of the No. 3, the No. 5 and the No. 6 treatments exceeds 5 days, which meets the relevant requirements of the domestic garbage compost, wherein the time for maintaining the high temperature period of the No. 6 treatments reaches 7 days at most, and the best decomposition effect is achieved. Then the temperature of the treated piles of each group is slowly reduced, after 21d, the temperature of the piles is close to the ambient temperature, and the compost is basically decomposed. The stack temperature analysis shows that the process condition of No. 6 treatment is the optimal scheme of the test, which is consistent with the visual analysis result of the orthogonal test.

2.3 variation of pH under different Process parameters

pH is an important indicator for evaluating the application capacity of compost productsAlso, the life activities of the microorganisms are affected. The compost pH change is shown in figure 2. The pH of treatments No. 1, 4, 7 and 9 showed a tendency to decrease first and then increase and finally to stabilize. The four groups of treatments have poor ventilation and oxygen supply effects, and the anaerobic fermentation of the pile body generates a large amount of organic acid to cause the pH value to be reduced; along with the continuous ventilation and the rising of the reactor temperature, the water content of the material is reduced, and the aerobic microorganisms decompose organic matters to generate NH₃Causing the pH to rise; reduction of easily decomposed organic matter and NH in the later period of composting₃The pH of the pack eventually becomes stable due to reduced volatilization. The pH of the rest of the treatments tends to increase and then decrease, and then tends to be stable. This indicates that the aeration and oxygen supply effects of the pile are good, and the microorganisms decompose the organic substances to produce a large amount of NH₃Causing the pH value of the pile to rise rapidly; NH as the temperature increases₃The large amount escapes, the pH value begins to drop, further the nitration reaction converts the ammonium nitrogen into nitrate nitrogen, and the pH value continues to drop; finally, the easily decomposed organic matters are exhausted, and the pH value of the pile tends to be stable. The pH of the final compost product is 6.69-7.06, meeting the requirements that the pH of the compost product should be between 5.5-8.5.

2.4 Change in EC under different Process parameters

EC represents the content of soluble salt in the compost and is an important embodiment of the mineralization degree of the compost material. Different plants have different tolerance degrees on EC, and the growth of the plants is not facilitated by over-high or under-low EC, so that the EC value can represent the toxic degree and the inhibition effect of the compost products on the plants to a certain extent. The compost substrate is mainly macromolecular organic matters, the EC value is low, and microorganisms decompose the organic matters to generate soluble salts such as phosphate, ammonium salt and the like in an aerobic environment after composting starts to cause the increase of EC; the volatilization of ammonia gas and the consumption of inorganic salt for the growth and reproduction of microorganisms lead the EC to be reduced, and the micromolecule inorganic salt synthesizes macromolecular humic acid at the later stage of composting, so that the EC is further reduced and finally tends to be stable. This explains the trend of the change that the EC value in FIG. 3 increases and then decreases and finally becomes stable, wherein the EC value in treatment No. 6 is the highest, which indicates that the decomposition effect of the organic substances is the best. The EC value of each processed final product is less than 4mS cm^-1And meets the requirements. Because the coffee grounds have special porous structures and have adsorption effect on soluble salts in the composting process, the EC value change amplitude is smaller, and the EC value change amplitude is reducedThe salinization risk of the compost product is reduced, and the repairing effect on the salinization soil is achieved.

2.5 Change of TN under different Process conditions

Nitrogen is a nutrient element necessary for plant growth and reproduction and is an important basis for measuring the fertilizer efficiency of compost products. The nitrogen conversion in the composting process comprises ammoniation, nitrification, denitrification and biological absorption and retention. Mineralization of organic nitrogen, persistent ammonia volatilization and denitrification of nitrate nitrogen are the major causes of compost nitrogen loss. The variation in TN treated by each group is shown in FIG. 4. The TN processed by nos. 1, 2, 3, 5 and 6 decreases in magnitude first, then increases continuously and tends to be stable. The temperature of the compost is raised to enable the ammonia gas to be rapidly volatilized, so that TN in the compost is reduced in a small degree; then the reactor temperature is increased, the decomposition rate of organic substances exceeds the loss rate of nitrogen, and the TN content is gradually increased although the volatilization of ammonia is continuously carried out. The TN content of No. 6 treated is increased most remarkably, which shows that the decomposition effect of the organic matters is the best, and the result of orthogonal analysis is also proved. The TN content of No. 7 and No. 9 treatment is in a descending trend, because the reactor body is locally anaerobic, and the nitrogen loss rate caused by ammonia volatilization and denitrification is higher than the organic matter decomposition rate.

2.6 GI Change under different Process conditions

GI is an important index for measuring the maturity and the practicability of the compost product, and can visually represent the phytotoxicity of the compost product. When GI reaches 80%, the compost product is considered to be non-phytotoxic, i.e. the compost is thoroughly decomposed. In the early stage of composting, microorganisms decompose organic matters to generate a large amount of ammonia gas and high NH₄ ⁺The content is such that a decrease in GI occurs; when the compost enters a high-temperature period, the GI of the compost rises rapidly and tends to be stable along with the large escape of ammonia gas and the acceleration of the decomposition of organic acid. This is consistent with the trend of the treatments No. 3, No. 5 and No. 6 in FIG. 5, wherein the GI of the treatment No. 6 is up to 94.59%, which indicates the best decomposition effect. GI of the rest treatments showed a steady rising trend, with treatments No. 4, No. 7, No. 8 and No. 9 showing NH levels due to shorter duration of high temperature₄ ⁺And more organic acid residues, and the GI of the sample is lower than 80 percent until the experiment is finished, so the sample cannot become thoroughly decomposed.

2.7 Ventilation improvement

The ventilation is one of the key factors for the success of high-temperature aerobic composting, is an important means for adjusting the oxygen concentration, the temperature and the water content of a compost body, and directly influences the microbial activity, the organic matter degradation rate and the temperature change. The reasonable ventilation mode can realize the rapid temperature rise of the compost, improve the quality of the compost and reduce the energy consumption. The timing on-off cycle control mode is a common control mode in high-temperature aerobic composting, and has the defects of simplicity and feasibility. In the research, temperature-oxygen content feedback control is adopted, and stack temperature and stack oxygen concentration are used as monitoring indexes to perform ventilation control, and the control logic is shown in table 3.

TABLE 3

When T is less than 25 ℃, the life activity of the composting microorganisms is low, the oxygen requirement is low, and the oxygen is sufficient after mixing, so ventilation is not needed; when T is more than or equal to 25 ℃ and less than 45 ℃, the compost enters a temperature rising stage, the oxygen consumption is accelerated, so that the oxygen content feedback control is adopted in the stage, when the oxygen concentration is less than 15%, a fan is started for ventilation for 5min, the ventilation is suspended for 15min, and the ventilation is stopped when the oxygen concentration is 19%; when the temperature T is more than or equal to 45 ℃ and less than 63 ℃, the compost enters a high-temperature stage, the oxygen content feedback control is also adopted, but the oxygen consumption rate is considered to be higher than that of a temperature rise stage, ventilation is carried out for 5min, and the time is suspended for 10 min; when T is more than 63 ℃, continuously ventilating, and stopping ventilating when the oxygen concentration is 19 percent.

The adoption of temperature-oxygen content control can effectively reduce the energy consumption of composting while ensuring sufficient oxygen supply.

3. Results and analysis of the experiments

3.1 Effect of draft on high temperature aerobic composting

The ventilation rate is one of the key control factors of high-temperature aerobic composting, and whether the ventilation rate is proper or not directly influences the temperature change of the composting, so that the quality of the composting product is influenced. The influence of ventilation on high-temperature aerobic composting has three main aspects: aeration can provide oxygen needed by aerobic microorganisms to sustain life activities; compostThe ventilation at the high temperature stage can take away the redundant moisture to realize the reduction of the materials; the ventilation can take away the redundant heat in the high-temperature stage, and the microorganisms are ensured to be in a reasonable temperature range. In this study, the optimal ventilation was 0.45[ L. (min. kg DM)^-1]. The content of organic matters in the coffee grounds is high, the oxygen requirement of the life activities of microorganisms cannot be guaranteed due to the fact that the content of the organic matters is lower than the optimal ventilation quantity, anaerobic reaction occurs, the time for maintaining the heap temperature at a high temperature is short, the decomposition effect of the organic matters and the quality of compost products are influenced, and drying of compost materials is not facilitated. But the low ventilation rate at the initial composting stage can reduce heat loss and is beneficial to the temperature rise of the compost. The proper increase of ventilation in the middle and later stages of the compost can provide sufficient oxygen, is beneficial to the growth and reproduction of compost microorganisms and the drying of materials, but also aggravates the loss of nitrogen and reduces the fertilizer efficiency of compost products.

3.2 influence of Water content on high-temperature aerobic composting

In the high-temperature aerobic composting process, moisture can provide a good medium for microorganisms to absorb nutrient substances, and a proper environmental condition is provided for the growth, the propagation and the metabolism of the microorganisms. The proper moisture condition can soften the material and accelerate the decomposition of the microorganism, and the movement of the moisture can ensure that the microorganism and the nutrient substance are uniformly distributed in the compost, thereby being beneficial to the smooth proceeding of the compost. When the moisture content is too high, the internal space of heap reduces, and the oxygen suppliment is not enough, easily forms anaerobic environment, is unfavorable for aerobic microorganism to survive, and easily produces the filtration liquid, increases treatment cost. And because the specific heat capacity of water is larger, the initial temperature rise of the pile body is slow due to overhigh water content, and the water loss is more unfavorable. In the research, the optimal water content is 55%, enough gaps can be provided in the temperature rise stage to ensure ventilation and oxygen supply, the water content can still meet the requirement of microorganism growth and propagation even if a large amount of water is lost in the high temperature stage, the water content is obviously reduced in the temperature reduction stage, and the energy consumption of material drying is reduced. Moreover, the water content of the fresh coffee grounds produced by the coffee shop is 50% -55%, the water content adjusting range is small, and water resources can be effectively saved.

3.3 influence of carbon-nitrogen ratio on high-temperature aerobic composting

Carbon and nitrogen ratio has important influence on the life activity of the composting microorganisms and the quality of the composting product. When the carbon-nitrogen ratio is lower, the nitrogen in the compost material is excessive, and the microorganisms decompose organic matters to cause great loss of the nitrogen, so that the emission of greenhouse gases is increased, and the fertilizer efficiency of the compost product is reduced; when the carbon-nitrogen ratio is too high, nitrogen in the compost material is insufficient, the growth of microorganisms is limited, and the decomposition of organic matters is slow. The carbon-nitrogen ratio of the coffee grounds generated by the coffee house is higher than 30, the carbon-nitrogen ratio can be adjusted by adding nitrogen sources such as urea and the like, the cost is low, and the compost is easy to start.

3.4 Effect of leavening agent addition on high temperature aerobic composting

The leavening agent is one of the common compost conditioners for improving the air permeability of the compost, and experiments show that the addition of the leavening agent can improve the material structure and improve the composting efficiency. The coffee grounds have smaller particle size, the compost material has less gaps, and the coffee grounds are extremely easy to compact in the composting process to cause local anaerobism. The addition of the leavening agent can increase the gaps of the pile body, enhance the diffusion of oxygen in the pile body, prolong the high-temperature period of compost and accelerate the decomposition of organic matters and the drying of materials. In the research, rice hulls are selected as a leavening agent, and the optimal addition amount is 9 percent (dry weight ratio). Excessive addition of the leavening agent can form redundant gaps, and the rapid air circulation is not favorable for heat preservation of the stack body; the structure of the pile body cannot be effectively improved due to insufficient addition of the leavening agent, and the phenomenon of pile body compaction naturally exists.

Example 1

An organic fertilizer taking coffee grounds as a main raw material comprises the following raw material components in percentage by weight (dry weight): 89.5% of coffee grounds, 1.4% of blending agent A urea and 9.1% of blending agent B rice hulls.

The aerobic composting process of the organic fertilizer taking the coffee grounds as the main raw material comprises the following steps:

(1) preparing materials: according to the formula proportion, the coffee grounds and the blending agent A are fully mixed, water is added to adjust the water content of the mixed material to be 55 percent, and the carbon-nitrogen ratio is 25; continuously adding rice hulls with the water content of 55% to obtain a premixed material;

(2) composting: putting the premixed material obtained in the step (1) into an adiabatic composting reactor, adding a high-temperature aerobic composting microbial inoculum which is 1 percent of the weight of the premixed material obtained in the step (1) for composting, performing aerobic composting fermentation, raising the central temperature of a compost to 55-63 ℃, and keeping for 5-7 days to finish primary fermentation; whereinThe high-temperature aerobic composting microbial inoculum is purchased from Shandong Junde Biotechnology limited company, and the effective viable count is more than or equal to 1 multiplied by 10¹⁰/mL；

When the temperature of the center of the pile is reduced to 25 ℃ from 60 ℃, completing the secondary fermentation to obtain the organic fertilizer, wherein the electric conductivity EC value of the obtained organic fertilizer is 0.83 mS-cm^-1The pH is 7.06, and the germination index GI of the seeds reaches 94.59%;

wherein, in the primary fermentation and the secondary fermentation, the ventilation rate is controlled to be 0.45L (min kg)^-1) Turning the piles on

days

1, 5, 9, 13, 17 and 21, namely turning the piles once every 4 days.

[ Fertilizer Effect test of organic fertilizers ]

Application of organic fertilizer to lily

The experiment adopts a potting mode, three lily bulbs are planted in each pot, the organic fertilizer obtained in the example 1 is applied as a base fertilizer, the application amount is 10-15% (dry weight ratio), blank soil and equal nitrogen fertilizer are used as a control, and no additional fertilizer is applied in the current season growth period, which is specifically shown in tables 4, 5 and 6.

TABLE 4 planting test treatment mode

Group of	Base fertilizer
		Treatment method
1	Is free of
		Treatment method 2	Example 1 organic fertilizer 10% (mass ratio)
Treatment method 3	10 percent (mass ratio) of fertilizer with the same nitrogen amount as the organic fertilizer

TABLE 5 growth of different lily plants

Group of	Plant height/cm of 30 days	Plant height/cm before flowering
			Treatment method 1	24	54
Treatment method 2	29	60.5
			Treatment method 3	32	57

TABLE 6 Effect of different fertilizers on the flowering phase of Lily

Group of	Average flowering time/d	Average number of flowers/flower	Diameter/cm of flower
				Treatment method
1	27	6	10.2
				Treatment method 2	31	6.3	13.5
Treatment method 3	29	6.3	11.7

As can be seen from tables 5 and 6, the application of the organic fertilizer obtained in example 1 can effectively promote the growth of lily plants, and is significantly better than the

treatment modes

1 and 3. In the treatment mode 3, the chemical fertilizer is applied, so that the plants grow vigorously in the early stage of growth, but the nutrient supply in the later stage is insufficient, so that the flowering phase is obviously shorter than that in the treatment mode 1, and additional fertilizer is needed; in the organic fertilizer of the embodiment 1, abundant humus can ensure that plants have sufficient nutrient supply in the current season growth, the plant growth is more facilitated, the flowering phase can be effectively prolonged, and flowers can be enlarged.

[ insect repellent test for organic fertilizers ]

In order to explore the insect expelling performance of the coffee residue compost, pillbug and snail are selected as research objects to carry out experiments. The insects used in the experiment are taken from a campus green belt, an experiment container is equally divided into 2 parts according to the area, soil is placed on one side, compost is placed on the other side, the water content is adjusted to be consistent, clover leaves with the same area are placed on two sides for snails to freely feed, and the avoidance performance of the insects is observed and counted, which is specifically shown in table 7.

TABLE 7 insect repellent effect of coffee grounds compost

	5min driving off/%)	10min driving off/%)	1h driving off/%)	6h driving off/%)
					Snail	53.3	60	86.7	93.3
Armadillidium vulgare (L.) pers	26.6	53.3	93.3	96.7

As can be seen from Table 7, the coffee grounds compost has a significant effect of repelling pillbugs and snails. In addition, the feeding area of the snail on the leaf on the compost placing side is only 38.9% of the feeding area of the leaf on the soil placing side in the experiment process. When the proportion of the compost is reduced to 30 percent of the soil, the 6h driving rate of the mixed soil to pillworm can still reach 60 percent. Therefore, the organic fertilizer can be used as an additional fertilizer, is directly coated on the pot soil, and has an insect expelling effect.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.

Claims

1. An organic fertilizer taking coffee grounds as a main raw material is characterized by comprising the following raw material components in percentage by weight: 80-90% of coffee grounds, 1-2% of a blending agent A and 8-13% of a blending agent B.

2. The organic fertilizer according to claim 1, wherein the blending agent A is a nitrogen-containing substance; the blending agent B is rice husk or wood dust.

3. The fertilizer as claimed in claim 2, wherein the nitrogen-containing substance is urea.

4. An aerobic composting process of organic fertilizer with coffee grounds as main raw materials according to any one of claims 1 to 3, characterized by comprising the following steps:

5. The aerobic composting process of claim 4 wherein the aeration and the amount of aeration are controlled in accordance withThe change of oxygen demand in the compost is adjusted in time, and the ventilation quantity is controlled to be 0.4-0.5L (min kg)^-1) The ventilation control is automatically performed in the following manner:

6. the aerobic composting process as claimed in claim 4, wherein the EC value of the conductivity of the premix material during composting varies in the range of 0.854-1.157 mS-cm^-1(ii) a The electric conductivity EC value of the obtained organic fertilizer is 0.845-0.877mS cm^-1。

7. The aerobic composting process as claimed in claim 4, wherein the pH of the organic fertilizer obtained is 6.92-7.06; the seed germination index GI of the obtained organic fertilizer reaches more than 85 percent.

8. The application of the organic fertilizer taking coffee grounds as a main raw material as a base fertilizer in the field of planting of potted ornamental plants of lily flowers and plants, which is disclosed by claim 1.

9. The application of the organic fertilizer taking coffee grounds as a main raw material as claimed in claim 1 in the field of plant insect repelling as an additional fertilizer.