Special chicken manure fermented fertilizer for pear trees as well as preparation method and application of special chicken manure fermented fertilizer

Abstract

The invention discloses a special chicken manure fermented fertilizer for pear trees as well as a preparation method and application thereof and belongs to the technical field of fertilizers. The chicken manure fermented fertilizer is prepared from the following raw materials in percentage by weight: 70 to 85 percent of fresh chicken manure, 5 to 10 percent of plant ash, 5 to 10 percent of fly ash, 1 to 4 percent of persulfate, 0.5 to 1 percent of EM fungicide and 3 to 5 percent of modified biomass charcoal, wherein the modified biomass charcoal is rice straw biomass charcoal modified by acylated chitosan and bamboo charcoal biomass charcoal, and the mass ratio of the rice straw biomass charcoal to the bamboo charcoal biomass charcoal is (2-4): 1. The special chicken manure fermented fertilizer for pear trees can reduce soil hardening, improve the air permeability and water and fertilizer retention of soil, and reduce the contents of heavy metals and antibiotics in the soil, thereby achieving the effects of increasing the yield of fruits and improving the quality of the fruits.

Description

Technical Field

[0001] The invention belongs to the technical field of fertilizers, and in particular relates to a chicken manure fermented fertilizer special for pear trees, and a preparation method and application thereof. Background Art

[0002] The pear tree is a perennial deciduous tree of the genus Pyrus in the Rosaceae family, which is widely distributed around the world. Its fruit has extremely high nutritional value and is sweet in taste, making it very popular. At present, in the cultivation and management of pear trees, in order to pursue yield and fruit quality, heavy metals introduced by the use of inorganic fertilizers, pesticides and other substances accumulate in the orchard soil. Under the influence of acid rain, the heavy metals in the soil are activated and gradually released, increasing the content of effective heavy metals in the soil, thereby increasing the risk of heavy metals entering the fruit trees, thereby affecting the growth of fruit trees and the quality of fruit, and affecting the high-quality development of the pear industry.

[0003] Chicken manure is rich in N, P, K nutrients and other trace elements, and is a high-quality source of organic fertilizer. However, due to the excessive addition of antibiotics and heavy metals in feed, a large amount of antibiotics and heavy metals remain in chicken manure, which seriously limits the use of chicken manure as organic fertilizer.

[0004] Patent CN106588220A discloses a fertilizer for fruit trees, which is composed of the following raw materials in parts by weight: 50-100 parts of straw powder, 60-90 parts of livestock and poultry manure, 20-40 parts of wood ash, 20-40 parts of acrylic acid, 10-20 parts of diammonium hydrogen phosphate, 10-30 parts of potassium dihydrogen phosphate, 0.5-4 parts of sodium tetraborate, 0.2-3 parts of boric acid, 0.5-6 parts of sodium glutamate, 0.1-5 parts of sodium alginate, 1-5 parts of amino acids, 0.2-4 parts of cellulose, and 1-5 parts of trace elements. Although the fertilizer for fruit trees can solve the problems of environmental pollution and high cost caused by the traditional application of inorganic fertilizers, the fertilizer for fruit trees only provides that the fertilizer has high fertility and improves the quality of fruits, but does not provide that the application of the fertilizer can reduce heavy metals and antibiotics, reduce soil compaction, and improve soil permeability and water retention, thereby achieving the effect of increasing fruit production. Summary of the invention

[0005] In view of the deficiencies in the prior art, the purpose of the present invention is to provide a special chicken manure fermented fertilizer for pear trees, and a preparation method and application thereof. The special chicken manure fermented fertilizer for pear trees can reduce soil compaction, improve soil permeability and water and fertilizer retention, and at the same time reduce the content of heavy metals and antibiotics in the soil, thereby achieving the effect of increasing fruit yield and improving quality.

[0006] In order to achieve the above-mentioned purpose, according to one aspect of the present invention, there is provided a special chicken manure fermented fertilizer for pear trees, which comprises the following raw materials by weight percentage: 70-85% fresh chicken manure, 5-10% wood ash, 5-10% fly ash, 1-4% persulfate, 0.5-1% EM bacterial agent and 3-5% modified biochar; wherein the modified biochar is acylated chitosan modified rice straw biochar and bamboo charcoal biochar, and the mass ratio of the rice straw biochar to the bamboo charcoal biochar is 2-4:1.

[0007] In the present invention, in the chicken manure fermented fertilizer for pear trees, the weight percentage of fresh chicken manure is 70-85%. It can be understood that the weight percentage can be any specific value of 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, or any value within the range of 70-85%. Preferably, the weight percentage of the fresh chicken manure is 70-80%.

[0008] In the present invention, the weight percentage of wood ash in the chicken manure fermented fertilizer for pear trees is 5-10%. It can be understood that the weight percentage can be any specific value among 5%, 6%, 7%, 8%, 9%, 10% or any value within the range of 5-10%.

[0009] In the present invention, in the chicken manure fermented fertilizer specially used for pear trees, the weight percentage of fly ash is 5-10%. It can be understood that the weight percentage can be any specific value among 5%, 6%, 7%, 8%, 9%, 10% or any value within the range of 5-10%.

[0010] In the present invention, the weight percentage of persulfate in the chicken manure fermented fertilizer for pear trees is 1-4%. It can be understood that the weight percentage can be any specific value of 1%, 2%, 3%, 4% or any value in the range of 1-4%. In the present invention, the persulfate includes at least one of sodium persulfate and potassium persulfate.

[0011] In the present invention, in the chicken manure fermented fertilizer specially used for pear trees, the weight percentage of the EM bacterial agent is 0.5-1%. It can be understood that the weight percentage can be any specific value among 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1% or any value within the range of 0.5-1%.

[0012] In the present invention, in the chicken manure fermented fertilizer for pear trees, the weight percentage of modified biochar is 3-5%. It can be understood that its weight percentage can be any specific value of 3%, 4%, 5% or any value within the range of 3-5%. In the present invention, the modified biochar is rice straw biochar and bamboo charcoal biochar modified by acylated chitosan, and the mass ratio of the rice straw biochar and the bamboo charcoal biochar is 2-4:1. It can be understood that its mass ratio can be any specific value of 2:1, 2.5:1, 3:1, 3.5:1, 4:1 or any value within the range of 2-4:1. Preferably, the mass ratio of the rice straw biochar and the bamboo charcoal biochar is 2-3:1. In the present invention, the acylated chitosan is obtained by acylation reaction of citric acid and chitosan. On the one hand, citric acid and chitosan undergo an acylation reaction, and some of the amino groups on the chitosan molecular structure are converted into amide bonds, thereby successfully introducing the carboxyl group of citric acid into the chitosan molecular structure, improving the adsorption of heavy metal ions. On the other hand, the rich oxygen-containing functional groups further activate the efficiency of persulfate in removing sulfadimethoxine, significantly improving the system's ability to remove sulfadimethoxine. The acylated chitosan-modified rice straw biochar and bamboo charcoal biochar work synergistically, thereby reducing soil compaction, improving soil permeability and water retention, and reducing the content of heavy metal ions and antibiotics in the soil.

[0013] In the present invention, the rice straw biomass charcoal is rice straw carbonized at 300-350°C, and it can be understood that it can be any specific value of 300°C, 310°C, 320°C, 330°C, 340°C, 350°C or any value within the range of 300-350°C. In the present invention, the bamboo charcoal biomass charcoal is bamboo charcoal carbonized at 550-600°C, and it can be understood that it can be any specific value of 550°C, 560°C, 570°C, 580°C, 590°C, 600°C or any value within the range of 550-600°C.

[0014] The inventors found that the surface functional groups of rice straw biochar carbonized at 300-350°C are rich, such as carboxylic acid, hydroxyl and carbonyl, while the pore structure of bamboo charcoal biochar carbonized at 550-600°C is well developed. The combination of the two ensures that the mixed biochar has both rich surface functional groups and well-developed pore structure, which provides sufficient reaction sites for the subsequent reaction with acylated chitosan, and ensures that there is still sufficient specific surface area and pore volume after the reaction, avoiding the acylated chitosan from clogging the pores of the biochar, thereby reducing the adsorption of NH 4+ 、NO 3-The addition of acylated chitosan introduces carboxyl groups into the system, thereby improving the adsorption of heavy metal ions, thereby reducing soil compaction, improving soil permeability and water retention, and reducing the content of heavy metal ions and antibiotics in the soil.

[0015] According to another aspect of the present invention, there is also provided a method for preparing the above-mentioned chicken manure fermented fertilizer for pear trees, comprising the following steps: (1) placing rice straw in a muffle furnace, carbonizing it at 300-350°C for 2-4 hours in a non-oxygen atmosphere, washing, drying, and crushing to obtain rice straw biochar; (2) placing the bamboo charcoal in a muffle furnace, carbonizing it at 550-600° C. in a non-oxygen atmosphere for 2-4 hours, washing, drying, and crushing to obtain bamboo charcoal biomass charcoal; (3) adding chitosan to an aqueous solution containing sodium hypophosphite and citric acid, stirring evenly, performing heat preservation reaction, precipitation, washing, and drying to obtain modified chitosan; (4) mixing the rice straw biochar obtained in step (1) and the bamboo charcoal biochar obtained in step (2) in proportion to obtain a mixed biochar; adding the mixed biochar to an aqueous solution in which the modified chitosan is dissolved, heating the mixture for reaction, and obtaining the modified biochar; (5) The fresh chicken manure, wood ash, fly ash, persulfate, EM bacterial agent and modified biochar are mixed evenly in proportion and aerobic composting is performed to obtain the chicken manure fermented fertilizer for pear trees.

[0016] In the present invention, in step (1), rice straw is placed in a muffle furnace, carbonized at 300-350°C for 2-4 hours in a non-oxygen atmosphere, washed, dried, and crushed to obtain rice straw biomass charcoal. Preferably, the length of the rice straw is 0.2-2 mm. Preferably, the carbonized rice straw is soaked in dilute hydrochloric acid for 12-24 hours, centrifuged, washed with water until neutral, dried at 70-80°C for 12-24 hours, ground and crushed, and passed through a 100-mesh sieve to obtain the rice straw biomass charcoal.

[0017] In the present invention, in step (2), the bamboo charcoal is placed in a muffle furnace, carbonized at 550-600°C for 2-4 hours in a non-oxygen atmosphere, washed, dried, and crushed to obtain bamboo charcoal biomass charcoal. Preferably, the length of the bamboo charcoal is 0.2-2 mm. Preferably, the carbonized bamboo charcoal is soaked in dilute hydrochloric acid for 12-24 hours, centrifuged, washed with water until neutral, dried at 70-80°C for 12-24 hours, ground and crushed, and passed through a 100-mesh sieve to obtain the bamboo charcoal biomass charcoal.

[0018] In the present invention, in step (3), chitosan is added to an aqueous solution containing sodium hypophosphite and citric acid, stirred evenly, subjected to heat preservation reaction, precipitated, washed, and dried to obtain modified chitosan. Preferably, the temperature of the heat preservation reaction is 110-120°C, and the time is 3-4h. Preferably, the molar mass ratio of the sodium hypophosphite and citric acid is 1:10-11, and the mass ratio of the chitosan and citric acid is 1:0.3-0.5. Preferably, after the heat preservation reaction, the system is cooled to room temperature, ethanol is added for precipitation, washed with water until neutral, and vacuum freeze-dried at -50--80°C for 24-36h to obtain modified chitosan. The inventors have found that the quality of chitosan and citric acid needs to be strictly controlled. If the content of citric acid is too high, the excess citric acid will cause the macromolecular chitosan to hydrolyze, thereby affecting the effect of activating persulfate to remove antibiotics and the ability to remove heavy metals.

[0019] In the present invention, in step (4), the rice straw biochar obtained in step (1) and the bamboo charcoal biochar obtained in step (2) are mixed in proportion to obtain a mixed biochar; the mixed biochar is added to an aqueous solution in which the modified chitosan is dissolved, and heated to react to obtain the modified biochar. Preferably, the mass ratio of the mixed biochar to the modified chitosan is 4:3-3.5. Preferably, the reaction temperature is 60-70°C and the reaction time is 5-8h.

[0020] In the present invention, in step (5), the fresh chicken manure, wood ash, fly ash, persulfate, EM bacterial agent and modified biochar are mixed evenly in proportion, and aerobic composting is performed to obtain the chicken manure fermented fertilizer for pear trees. Preferably, the fresh chicken manure, wood ash, fly ash, persulfate and modified biochar are mixed evenly in proportion, EM bacterial agent is added and mixed, and the water content is adjusted to 35-50% and then aerobic fermentation is performed at a temperature of 50-60°C, and the compost is turned every 2-3 days for 15-21 days to obtain the chicken manure fermented fertilizer for pear trees.

[0021] According to another aspect of the present invention, there is also provided a use of the above-mentioned chicken manure fermented fertilizer for pear trees or the chicken manure fermented fertilizer for pear trees prepared according to the above-mentioned preparation method in fertilizing pear trees.

[0022] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention adds a certain amount of acylated chitosan modified biochar to the chicken manure fermented fertilizer, and further controls the mass ratio of rice straw biochar to bamboo charcoal biochar in the modified biochar. The two act synergistically, so that the chicken manure fermented fertilizer can reduce soil compaction, improve soil permeability and water retention, and reduce the content of heavy metals and antibiotics in the soil, thereby achieving the effect of increasing fruit yield and improving quality.

[0023] (2) The present invention further regulates the carbonization temperature of the rice straw biochar and the bamboo charcoal biochar so that the prepared rice straw biochar and the bamboo charcoal biochar have a developed pore structure and abundant surface functional groups, thereby further improving the fertilizer preservation effect of the chicken manure fermented fertilizer.

[0024] (3) The present invention also provides a method for preparing chicken manure fermented fertilizer for pear trees, in particular, by controlling the ratio of sodium hypophosphite, citric acid and chitosan to obtain a specific acylated chitosan, and then using the acylated chitosan to modify rice straw biochar and bamboo charcoal biochar to obtain a modified biochar, so that the chicken manure fermented fertilizer for pear trees obtained by using the modified biochar has the effects of reducing soil compaction, improving soil permeability and water retention, and reducing the content of heavy metals and antibiotics in the soil. DETAILED DESCRIPTION

[0025] In order to enable those skilled in the art to understand the characteristics and effects of the present invention, the following is a general description and definition of the terms and expressions mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used in the text are the common meanings understood by those skilled in the art for the present invention. In the event of a conflict, the definition in this specification shall prevail.

[0026] The theories or mechanisms described and disclosed herein, whether correct or incorrect, should not limit the scope of the present invention in any way, that is, the present invention can be implemented without being limited by any specific theory or mechanism.

[0027] Herein, when describing embodiments or examples, it should be understood that they are not used to limit the present invention to these embodiments or examples. On the contrary, all substitutes, improvements and equivalents of the methods and materials described in the present invention can be included in the scope limited by the claims.

[0028] In this document, in order to make the description concise, not all possible combinations of various technical features in various embodiments or examples are described. Therefore, as long as there is no contradiction in the combination of these technical features, the various technical features in various embodiments or examples can be combined arbitrarily, and all possible combinations should be considered to be within the scope of this specification.

[0029] The invention provides a special chicken manure fermented fertilizer for pear trees, which comprises the following raw materials by weight percentage: 70-85% fresh chicken manure, 5-10% wood ash, 5-10% fly ash, 1-4% persulfate, 0.5-1% EM bacterial agent and 3-5% modified biochar; wherein the modified biochar is acylated chitosan-modified rice straw biochar and bamboo charcoal biochar, and the mass ratio of the rice straw biochar to the bamboo charcoal biochar is 2-4:1.

[0030] In the present invention, the acylated chitosan is obtained by acylation reaction of citric acid and chitosan.

[0031] In the present invention, the rice straw biomass charcoal is rice straw carbonized at 300-350°C, and the bamboo charcoal biomass charcoal is bamboo charcoal carbonized at 550-600°C.

[0032] In the present invention, the persulfate includes at least one of sodium persulfate and potassium persulfate.

[0033] According to another aspect of the present invention, there is also provided a method for preparing the above-mentioned chicken manure fermented fertilizer for pear trees, comprising the following steps: (1) placing rice straw in a muffle furnace, carbonizing it at 300-350°C for 2-4 hours in a non-oxygen atmosphere, washing, drying, and crushing to obtain rice straw biochar; (2) placing the bamboo charcoal in a muffle furnace, carbonizing it at 550-600° C. in a non-oxygen atmosphere for 2-4 hours, washing, drying, and crushing to obtain bamboo charcoal biomass charcoal; (3) adding chitosan to an aqueous solution containing sodium hypophosphite and citric acid, stirring evenly, performing heat preservation reaction, precipitation, washing, and drying to obtain modified chitosan; (4) mixing the rice straw biochar obtained in step (1) and the bamboo charcoal biochar obtained in step (2) in proportion to obtain a mixed biochar; adding the mixed biochar to an aqueous solution in which the modified chitosan is dissolved, heating the mixture for reaction, and obtaining the modified biochar; (5) The fresh chicken manure, wood ash, fly ash, persulfate, EM bacterial agent and modified biochar are mixed evenly in proportion and aerobic composting is performed to obtain the chicken manure fermented fertilizer for pear trees.

[0034] In the present invention, in step (3), the temperature of the heat preservation reaction is 110-120° C. and the time is 3-4 hours.

[0035] In the present invention, in step (3), the molar mass ratio of the sodium hypophosphite to the citric acid is 1:10-11, and the mass ratio of the chitosan to the citric acid is 1:0.3-0.5.

[0036] In the present invention, in step (4), the mass ratio of the mixed biochar to the modified chitosan is 4:3-3.5.

[0037] In the present invention, in step (4), the reaction temperature is 60-70° C. and the reaction time is 5-8 h.

[0038] According to another aspect of the present invention, there is also provided a use of the above-mentioned chicken manure fermented fertilizer for pear trees or the chicken manure fermented fertilizer for pear trees prepared according to the above-mentioned preparation method in fertilizing pear trees.

[0039] The present invention will be described in detail below by way of examples. It should be understood that the following examples are only used to further explain and illustrate the content of the present invention by way of example, and are not intended to limit the present invention.

[0040] The best embodiment is embodiment 1.

[0041] The chemical additives used in the examples and comparative examples of the present invention are all commercially available, and their specific information is as follows: Fresh chicken manure: purchased from a local chicken farm; wood ash: purchased from Yinong Organic Fertilizer Factory, Donghua Town, Chuxiong City; fly ash: purchased from Yantai Power Plant; sodium persulfate, potassium persulfate, chitosan, ethanol, sodium hypophosphite and citric acid: all purchased from Aladdin Reagent; EM bacterial agent: general type, with a bacterial content between 10 million and 1 billion, purchased from Luoyang Oukebaik Biotechnology Co., Ltd.; rice straw and bamboo charcoal: length 0.2-2 mm, all purchased from Dezhou City, Shandong Province, China.

[0042] Example 1 The chicken manure fermented fertilizer for pear trees described in this embodiment includes the following raw materials, by weight percentage: 80% fresh chicken manure, 7% wood ash, 8% fly ash, 1.5% sodium persulfate, 0.5% EM bacterial agent and 3% modified biochar; wherein the modified biochar is rice straw biochar and bamboo charcoal biochar modified by acylated chitosan, and the mass ratio of the rice straw biochar to the bamboo charcoal biochar is 3:1.

[0043] The preparation method of the chicken manure fermented fertilizer for pear trees described in this embodiment comprises the following steps: (1) placing 20 g of rice straw in a muffle furnace, carbonizing at 300° C. for 4 h in a non-oxygen atmosphere, soaking in dilute hydrochloric acid for 24 h, centrifuging, washing with water until neutral, drying at 80° C. for 12 h, grinding and crushing, and passing through a 100-mesh sieve to obtain the rice straw biochar; (2) 20 g of bamboo charcoal was placed in a muffle furnace, carbonized at 600 °C for 2 h in a non-oxygen atmosphere, soaked in dilute hydrochloric acid for 24 h, centrifuged, washed with water until neutral, dried at 80 °C for 12 h, ground and crushed, and passed through a 100-mesh sieve to obtain bamboo charcoal biomass charcoal; (3) Add 10 g of chitosan to 20 ml of an aqueous solution containing 0.15 g of sodium hypophosphite and 3 g of citric acid, stir evenly, and react at 120 °C for 3 h. Cool the system to room temperature, add 85% ethanol for precipitation, wash with water until neutral, and freeze-dry at -50 °C for 36 h to obtain modified chitosan. (4) Mixing 3 g of the rice straw biochar obtained in step (1) and 1 g of the bamboo charcoal biochar obtained in step (2) to obtain a mixed biochar; adding 4 g of the mixed biochar to an aqueous solution containing 3 g of the modified chitosan, and reacting at 70° C. for 5 h to obtain the modified biochar; (5) The fresh chicken manure, wood ash, fly ash, sodium persulfate and modified biochar are mixed evenly in proportion, EM bacterial agent is added and mixed evenly, the moisture content is adjusted to 50%, and then aerobic fermentation is carried out at a temperature of 50° C. The pile is turned over every 3 days and fermented for 21 days to obtain the chicken manure fermented fertilizer for pear trees.

[0044] Example 2 The chicken manure fermented fertilizer for pear trees described in this embodiment includes the following raw materials, by weight percentage: 85% fresh chicken manure, 5% wood ash, 5% fly ash, 1% potassium persulfate, 1% EM bacterial agent and 3% modified biochar; wherein the modified biochar is rice straw biochar and bamboo charcoal biochar modified by acylated chitosan, and the mass ratio of the rice straw biochar to the bamboo charcoal biochar is 2:1.

[0045] The preparation method of the chicken manure fermented fertilizer for pear trees described in this embodiment comprises the following steps: (1) placing 20 g of rice straw in a muffle furnace, carbonizing at 350° C. for 2 h in a non-oxygen atmosphere, soaking in dilute hydrochloric acid for 12 h, centrifuging, washing with water until neutral, drying at 70° C. for 24 h, grinding and crushing, and passing through a 100-mesh sieve to obtain the rice straw biochar; (2) 20 g of bamboo charcoal was placed in a muffle furnace, carbonized at 550 °C for 4 h in a non-oxygen atmosphere, soaked in dilute hydrochloric acid for 12 h, centrifuged, washed with water until neutral, dried at 70 °C for 24 h, ground and crushed, and passed through a 100-mesh sieve to obtain bamboo charcoal biomass charcoal; (3) Add 10 g of chitosan to 20 ml of an aqueous solution containing 0.22 g of sodium hypophosphite and 5 g of citric acid, stir evenly, and react at 110 °C for 4 h. Cool the system to room temperature, add 85% ethanol for precipitation, wash with water until neutral, and freeze-dry at -80 °C in a vacuum freeze-drying process for 24 h to obtain modified chitosan. (4) Mixing 4 g of the rice straw biochar obtained in step (1) and 2 g of the bamboo charcoal biochar obtained in step (2) to obtain a mixed biochar; adding 4 g of the mixed biochar to an aqueous solution containing 3.5 g of the modified chitosan, and reacting at 60° C. for 8 h to obtain the modified biochar; (5) The fresh chicken manure, wood ash, fly ash, potassium persulfate and modified biochar are mixed evenly in proportion, EM bacterial agent is added and mixed evenly, the moisture content is adjusted to 35%, and then aerobic fermentation is carried out at a temperature of 60° C. The pile is turned over every 3 days and fermented for 15 days to obtain the chicken manure fermented fertilizer for pear trees.

[0046] Example 3 The chicken manure fermented fertilizer for pear trees described in this embodiment includes the following raw materials, by weight percentage: 70% fresh chicken manure, 10% wood ash, 10% fly ash, 4% sodium persulfate, 1% EM bacterial agent and 5% modified biochar; wherein the modified biochar is rice straw biochar and bamboo charcoal biochar modified by acylated chitosan, and the mass ratio of the rice straw biochar to the bamboo charcoal biochar is 4:1.

[0047] The preparation method of the chicken manure fermented fertilizer for pear trees described in this embodiment comprises the following steps: (1) placing 20 g of rice straw in a muffle furnace, carbonizing at 350° C. for 2 h in a non-oxygen atmosphere, soaking in dilute hydrochloric acid for 24 h, centrifuging, washing with water until neutral, drying at 80° C. for 12 h, grinding and crushing, and passing through a 100-mesh sieve to obtain the rice straw biochar; (2) 20 g of bamboo charcoal was placed in a muffle furnace, carbonized at 600 °C for 2 h in a non-oxygen atmosphere, soaked in dilute hydrochloric acid for 24 h, centrifuged, washed with water until neutral, dried at 80 °C for 12 h, ground and crushed, and passed through a 100-mesh sieve to obtain bamboo charcoal biomass charcoal; (3) Add 10 g of chitosan to 20 ml of an aqueous solution containing 0.15 g of sodium hypophosphite and 3 g of citric acid, stir evenly, and react at 120 °C for 3 h. Cool the system to room temperature, add 85% ethanol for precipitation, wash with water until neutral, and freeze-dry at -50 °C for 36 h to obtain modified chitosan. (4) Mixing 4 g of the rice straw biochar obtained in step (1) and 1 g of the bamboo charcoal biochar obtained in step (2) to obtain a mixed biochar; adding 4 g of the mixed biochar to an aqueous solution containing 3 g of the modified chitosan, and reacting at 60° C. for 8 h to obtain the modified biochar; (5) The fresh chicken manure, wood ash, fly ash, sodium persulfate and modified biochar are mixed evenly in proportion, EM bacterial agent is added and mixed evenly, the moisture content is adjusted to 50%, and then aerobic fermentation is carried out at a temperature of 50° C. The pile is turned over every 3 days and fermented for 21 days to obtain the chicken manure fermented fertilizer for pear trees.

[0048] Comparative Example 1 The preparation method of the chicken manure fermented fertilizer in this comparative example is exactly the same as that in Example 1, except that the modified biochar is rice straw biochar and bamboo charcoal biochar modified by acylated chitosan, and the mass ratio of the rice straw biochar to the bamboo charcoal biochar is 1:1.

[0049] Comparative Example 2 The preparation method of the chicken manure fermented fertilizer in this comparative example is exactly the same as that in Example 1, except that the modified biochar is rice straw biochar and bamboo charcoal biochar modified by acylated chitosan, and the mass ratio of the rice straw biochar to the bamboo charcoal biochar is 6:1.

[0050] Comparative Example 3 The preparation method of the chicken manure fermented fertilizer in this comparative example is exactly the same as that in Example 1, except that the modified biochar is chitosan-modified rice straw biochar and bamboo charcoal biochar.

[0051] Comparative Example 4 The preparation method of the chicken manure fermented fertilizer in this comparative example is exactly the same as that in Example 1, except that the rice straw biomass is rice straw carbonized at 250°C, that is, step (1) specifically comprises: placing 20 g of rice straw in a muffle furnace, carbonizing at 250°C for 4 h in a non-oxygen atmosphere, soaking in dilute hydrochloric acid for 24 h, centrifuging, washing with water until neutral, drying at 80°C for 12 h, grinding and crushing, and passing through a 100-mesh sieve to obtain the rice straw biomass charcoal.

[0052] Comparative Example 5 The preparation method of the chicken manure fermented fertilizer in this comparative example is exactly the same as that in Example 1, except that the bamboo charcoal biomass charcoal is bamboo charcoal carbonized at 700°C, that is, step (2) is specifically as follows: 20 g of bamboo charcoal is placed in a muffle furnace, carbonized at 700°C for 2 h in a non-oxygen atmosphere, soaked in dilute hydrochloric acid for 24 h, centrifuged, washed with water until neutral, dried at 80°C for 12 h, ground and crushed, and passed through a 100-mesh sieve to obtain bamboo charcoal biomass charcoal.

[0053] Comparative Example 6 The preparation method of the chicken manure fermented fertilizer in this comparative example is exactly the same as that in Example 1, the only difference is that in step (3), the mass ratio of chitosan to citric acid is 1:1.

[0054] Performance Testing Basic soil index test: A pear orchard was selected for the experiment. Ten treatment groups were set up in the experiment. The soil area in each treatment group was 100m 2 , each group of treatments has 10 pear trees, and the drought degree of the soil in each group of treatments is the same. The 10 groups of treatments are: no fertilizer is applied to the soil, and the chicken manure fermented fertilizer prepared by Examples 1-3 and Comparative Examples 1-6 are applied respectively. Before turning over and preparing the land, it is applied as a base fertilizer, wherein the fertilizer application rate is 80kg / mu, and other field management measures are the same as the conventional method, and each treatment group is the same. After 6 months, the basic indicators of the soil are tested. The specific results are shown in Table 1.

[0055] (1) Soil moisture content: Use TZS-1K soil moisture rapid tester to measure the moisture content 10 cm and 20 cm below the soil surface.

[0056] (2) Soil porosity: Soil bulk density shall be measured in accordance with NY / T1121.4-2006, and soil particle density shall be measured in accordance with NY / T1121.23-2010. In combination with the definition of soil porosity, soil porosity shall be calculated based on soil bulk density and soil particle density.

[0057] (3) Soil organic matter content: Soil organic matter content was measured in accordance with NY884-2012, on a dry basis.

[0058] (4) Soil nitrate nitrogen content: The nitrate nitrogen content at 10 cm and 20 cm below the soil surface was measured by ultraviolet spectrophotometry.

[0059] Table 1 Basic soil index data of Examples 1-3 and Comparative Examples 1-6 .

[0060] As shown in Table 1, after applying the chicken manure fermented fertilizer described in Examples 1-3 of the present invention, the porosity of the soil is relatively large, and the soil nitrate nitrogen content, water content and organic matter content at 10cm and 20cm are relatively high, indicating that the chicken manure fermented fertilizer described in the embodiment of the present invention can reduce soil compaction, improve soil permeability, and improve the water retention and fertilizer retention effect of the soil. As shown in Example 1 and Comparative Example 1, the rice straw biomass charcoal content in Comparative Example 1 is low, and the soil nitrate nitrogen content and water content at 10cm are reduced, indicating that the water retention and fertilizer retention are poor. As shown in Example 1 and Comparative Example 2, the rice straw biomass charcoal content in Comparative Example 2 is high, and the soil nitrate nitrogen content and water content at 20cm are reduced, indicating that the water retention and fertilizer retention are poor. As shown in Example 1 and Comparative Example 3, the modified biomass charcoal in Comparative Example 3 is directly modified using chitosan, and the porosity, soil nitrate nitrogen content, water content and organic matter content of the soil are reduced. It can be seen from Example 1 and Comparative Example 4 that the carbonization temperature of the rice straw biomass in Comparative Example 4 is low, and the porosity, soil nitrate nitrogen content, water content and organic matter content of the soil are all reduced, indicating that the low carbonization temperature leads to the imperfect development of the pore structure of the rice straw biomass, thereby affecting the water retention and fertilizer retention. It can be seen from Example 1 and Comparative Example 5 that the carbonization temperature of the bamboo charcoal biomass charcoal in Comparative Example 5 is high, and the porosity, soil nitrate nitrogen content, water content and organic matter content of the soil are all reduced, indicating that the high carbonization temperature causes the collapse of some pores of the bamboo charcoal biomass, affecting the subsequent acylated chitosan modification, thereby affecting the water retention and fertilizer retention. It can be seen from Example 1 and Comparative Example 6 that the content of citric acid in Comparative Example 6 is high, and the modification of the mixed biomass is imperfect, resulting in the water retention and fertilizer retention of the fermented fertilizer being affected.

[0061] Fruit quality test: When the fruit was ripe, two fruits were randomly collected from each pear tree in each treatment group for fruit quality test. See Table 2 for specific data.

[0062] (1) Soluble sugar content: Soluble solid content was measured using a PAL-1 electronic refractometer. (2) Soluble solids: The soluble sugar content was determined by anthrone colorimetry.

[0063] (3) Titratable acid: Determined by standard acid-base titration method.

[0064] (4) Yield per tree: The average yield per tree is calculated based on the yield of 10 fruit trees in each group.

[0065] Table 2 Fruit performance data of Examples 1-3 and Comparative Examples 1-6 .

[0066] It can be seen from Table 2 that the application of the chicken manure fermented fertilizer described in Examples 1-3 of the present invention is more conducive to improving the quality of pear fruit and effectively increasing the yield. However, the application of the chicken manure fermented fertilizer in Comparative Examples 1-6 reduced the quality and yield of pear fruit to varying degrees.

[0067] Heavy metal concentration test in soil: Six months after fertilization, soil 10 cm below the soil surface in each treatment group was taken and digested using nitric acid, perchloric acid, and hydrofluoric acid pressure tank methods. The heavy metal elements (Cr, Cd, Cu) were determined using the American Thermoelectric Solar M6 atomic absorption spectrometer.

[0068] Sulfadimethoxine test in soil: Six months after fertilization, soil 10 cm below the soil surface in each treatment group was taken and the concentration of sulfadimethoxine was determined by high performance liquid chromatography.

[0069] Table 3 Heavy metal and antibiotic removal performance data of Examples 1-3 and Comparative Examples 1-6 .

[0070] As shown in Table 3, the chicken manure fermented fertilizer described in Examples 1-3 of the present invention has excellent removal ability for heavy metals and antibiotics, especially for heavy metals Cr, Cd, Cu and sulfadimethoxine. It can be seen from Example 1 and Comparative Examples 1 and 2 that the fermented fertilizer in Comparative Example 1 has a poor adsorption effect on heavy metals Cr, Cd, Cu and sulfadimethoxine due to the low content of rice straw biochar, and the fermented fertilizer in Comparative Example 2 has a low content of bamboo charcoal biochar, which leads to partial pore blockage after acylated chitosan modification, thereby affecting the acylated chitosan from playing a role, resulting in poor removal effect on heavy metals Cr, Cd, Cu and sulfadimethoxine. It can be seen from Example 1 and Comparative Example 3 that the modified biochar in Comparative Example 3 is directly modified with chitosan, and its removal effect on heavy metals Cr, Cd, Cu and sulfadimethoxine is significantly reduced. It can be seen from Example 1 and Comparative Examples 4 and 5 that the carbonization temperature of the rice straw biomass charcoal in Comparative Example 4 is low, and the functional group content on the surface of the rice straw biomass is insufficient, which affects the removal of heavy metals Cr, Cd, Cu and sulfadimethoxine. The carbonization temperature of the bamboo charcoal biomass charcoal in Comparative Example 5 is too high, resulting in partial pore collapse, thereby affecting the modification efficiency of the acylated chitosan, resulting in a reduction in the removal effect of heavy metals Cr, Cd, Cu and sulfadimethoxine. It can be seen from Example 1 and Comparative Example 6 that the content of citric acid in Comparative Example 6 is high, and the modification of the mixed biomass is imperfect, resulting in a poor removal effect of heavy metals Cr, Cd, Cu and sulfadimethoxine.

[0071] It can be seen that the present invention provides a chicken manure fermented fertilizer specially used for pear trees by controlling the components and the preparation method. The chicken manure fermented fertilizer can reduce soil compaction, improve soil permeability and water and fertilizer retention, and at the same time reduce the content of heavy metals and antibiotics in the soil, thereby achieving the effect of increasing fruit yield and improving quality.

[0072] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not limitations on the implementation methods of the present invention. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is impossible to list all the implementation methods here. All obvious changes or modifications derived from the technical solution of the present invention are still within the protection scope of the present invention.

Claims

1. A chicken manure fermented fertilizer for pear trees, characterized in that: The following raw materials are included by weight percentage: 70-85% fresh chicken manure, 5-10% wood ash, 5-10% fly ash, 1-4% persulfate, 0.5-1% EM bacterial agent and 3-5% modified biochar; wherein the modified biochar is rice straw biochar and bamboo charcoal biochar modified by acylated chitosan, and the mass ratio of the rice straw biochar to the bamboo charcoal biochar is 2-4:

1.

2. The chicken manure fermented fertilizer for pear trees according to claim 1, characterized in that: The acylated chitosan is obtained by acylation reaction of citric acid and chitosan.

3. The chicken manure fermented fertilizer for pear trees according to claim 1, characterized in that: The rice straw biomass charcoal is rice straw carbonized at 300-350°C, and the bamboo charcoal biomass charcoal is bamboo charcoal carbonized at 550-600°C.

4. The chicken manure fermented fertilizer for pear trees according to claim 1, characterized in that: The persulfate includes at least one of sodium persulfate and potassium persulfate.

5. The method for preparing a chicken manure fermented fertilizer for pear trees according to any one of claims 1 to 4, characterized in that: The steps include: (1) placing rice straw in a muffle furnace, carbonizing it at 300-350°C for 2-4 hours in a non-oxygen atmosphere, washing, drying, and crushing to obtain rice straw biochar; (2) placing the bamboo charcoal in a muffle furnace, carbonizing it at 550-600° C. in a non-oxygen atmosphere for 2-4 hours, washing, drying, and crushing to obtain bamboo charcoal biomass charcoal; (3) adding chitosan to an aqueous solution containing sodium hypophosphite and citric acid, stirring evenly, performing heat preservation reaction, precipitation, washing, and drying to obtain modified chitosan; (4) mixing the rice straw biochar obtained in step (1) and the bamboo charcoal biochar obtained in step (2) in proportion to obtain a mixed biochar; adding the mixed biochar to an aqueous solution in which the modified chitosan is dissolved, heating the mixture for reaction, and obtaining the modified biochar; (5) The fresh chicken manure, wood ash, fly ash, persulfate, EM bacterial agent and modified biochar are mixed evenly in proportion and aerobic composting is performed to obtain the chicken manure fermented fertilizer for pear trees.

6. The method for preparing a chicken manure fermented fertilizer for pear trees according to claim 5, characterized in that: In step (3), the temperature of the insulation reaction is 110-120° C. and the time is 3-4 hours.

7. The method for preparing a chicken manure fermented fertilizer for pear trees according to claim 5, characterized in that: In step (3), the molar mass ratio of the sodium hypophosphite to the citric acid is 1:10-11, and the mass ratio of the chitosan to the citric acid is 1:0.3-0.

5.

8. The method for preparing a chicken manure fermented fertilizer for pear trees according to claim 5, characterized in that: In step (4), the mass ratio of the mixed biochar to the modified chitosan is 4:3-3.

5.

9. The method for preparing a chicken manure fermented fertilizer for pear trees according to claim 5, characterized in that: In step (4), the reaction temperature is 60-70°C and the reaction time is 5-8h.

10. Use of the fermented chicken manure fertilizer for pear trees according to any one of claims 1 to 4 or the fermented chicken manure fertilizer for pear trees prepared according to the preparation method according to any one of claims 5 to 9 in fertilizing pear trees.