CN111116272A - Soil conditioner for reducing nitrate nitrogen residue in soil of greenhouse vegetable field and preparation method thereof - Google Patents

Abstract

The invention discloses a soil conditioner for reducing nitrate nitrogen residues in soil of greenhouse vegetable fields and a preparation method thereof, wherein the soil conditioner comprises, by weight, 70-80 parts of corn stalk carbon, 20-25 parts of zeolite, 15-25 parts of fly ash, 15-25 parts of animal waste, 15-25 parts of EM stock solution, 10-15 parts of nitrification inhibitor and 5-10 parts of urea. The preparation method comprises the steps of firstly, impregnating the straw powder into the activating solution, and then carbonizing at low temperature to obtain the corn straw charcoal; then mixing the raw materials except the EM stock solution, spraying the activated EM microbial inoculum while stirring, and adjusting the water content of the materials to 45-55%; coating a film, fermenting, drying, crushing and molding. The soil conditioner can reduce redundant nitrate nitrogen residues in soil, increase the porosity of the soil, increase various trace nutrient elements required by the soil and play a role in repairing the soil.

Description

Soil conditioner for reducing nitrate nitrogen residue in soil of greenhouse vegetable field and preparation method thereof

Technical Field

The invention relates to the technical field of agriculture, in particular to a conditioner for reducing nitrate nitrogen residues in soil of a facility vegetable field.

Background

With the rapid development of modern agriculture, the production of the facility vegetable field is more and more extensive and common, the yield of agricultural products produced by the facility vegetable field is greatly improved, great economic benefits are brought, meanwhile, a series of problems such as hardening, pollution, organic matter reduction, microecological imbalance and the like are brought to the soil, and the problem of residual excessive nitrate nitrogen in the soil is particularly outstanding.

Production of facility vegetables is often accompanied by higher nitrogen input, more frequent farming and irrigation. The nitrogen application amount is usually higher than the nitrogen demand of vegetables, and the utilization efficiency of the nitrogen fertilizer is lower. Excessive nitrogen causes the content of organic matters in soil of a farmland plough layer to be reduced, nitrate to rise, the soil structure to be damaged and a microbial community to be unbalanced, and finally the water and fertilizer retention capacity of the soil is reduced and the biological effectiveness of the fertilizer is reduced. Excessive nitrate nitrogen in soil is not easy to be adsorbed and fixed by soil, and pollutes underground water sources in a leaching migration mode under rainfall and irrigation conditions, thereby causing huge pressure on the ecological environment. Therefore, the application of the soil conditioner for effectively reducing the nitrate nitrogen residue in the soil of the greenhouse vegetable field is very important, the soil conditioner can effectively improve the soil structure, improve the soil fertility and protect the ecological environment, and the soil conditioner has important significance for the sustainable development of agriculture.

China is a big agricultural country, the number of byproducts is continuously increased along with the development of agriculture, according to statistics, the number of crop straws per year in China is about 5 hundred million t, only a small part of the byproducts are reused, and a large amount of the byproducts are accumulated to cause serious environmental problems. Therefore, the agricultural wastes with huge quantity are fully developed and utilized to prepare the soil conditioner, and the method is very important for changing waste into valuable.

The fly ash is waste residue discharged by a thermal power plant taking coal as fuel, and the quantity of the fly ash is large, and about 0.5kg of fly ash can be generated every one-degree electricity production. The disposal of the fly ash in China is mainly performed by ash storage yard heaps, the fly ash is light and thin after being dehydrated, and flies everywhere in windy weather, thus seriously polluting atmosphere and environment. Along with the development of electric power, the discharge amount of fly ash is also greatly increased, and if the discharge amount of fly ash is not reasonably solved, serious environmental problems are caused. The fly ash is a substance which has stable chemical properties and the same properties as inorganic minerals such as natural clay and the like, and can be considered as a good agricultural resource, so that the development of the fly ash as a soil conditioner is gradually a hot spot of wide attention.

With the development of grain production and the improvement of the living standard of people, the livestock husbandry of China is increasingly developed, the excretion amount of the livestock manure is large, and the concentration of pollutants is high. If the animal waste is not properly treated, the animal waste is discharged into the water bodies of rivers and lakes, so that serious water body pollution can be caused.

The main components of the poultry manure are crude fiber, protein, sugar and fat substances, which are easily decomposed in nature and participate in the substance recycling process. The soil conditioner is processed and prepared by fully utilizing the circulation way, and the nutrient substances in the excrement and the urine can be utilized, and the harm to the environment is avoided.

Disclosure of Invention

In view of the above problems, an object of the present invention is to provide a soil conditioner for reducing nitrate nitrogen residues in soil of greenhouse vegetable fields and a method for producing the same, which are intended to solve the problems of soil pollution, decrease in fertility, and the like caused by excessive nitrate nitrogen residues in soil of conventional greenhouse vegetable fields.

In order to achieve the above object, the embodiments of the present invention provide the following technical solutions:

a soil conditioner for reducing nitrate nitrogen residue in soil of a facility vegetable field comprises the following raw materials in parts by weight:

70-80 parts of corn stalk carbon, 20-25 parts of zeolite, 15-25 parts of fly ash, 15-25 parts of animal waste, 15-25 parts of EM stock solution, 10-15 parts of nitrification inhibitor and 5-10 parts of urea.

Preferably, the biological fertilizer comprises 75 parts of corn stalk charcoal, 23 parts of zeolite, 20 parts of fly ash, 20 parts of animal manure, 20 parts of EM stock solution, 13 parts of nitrification inhibitor and 8 parts of urea. Because the proportion of the raw materials is close to 9: 3: 2.5: 1.5, the improvement on the physical and chemical properties of the soil is most obvious, and the optimal conditioning effect can be achieved. And the solid-liquid ratio of the conditioner is close to 4: 1, which is beneficial to various operations during mixing and preparation of the conditioner and is easy to obtain the soil conditioner with moderate humidity.

The corn stalk charcoal is prepared by peeling air-dried corn stalk, cleaning with deionized water to remove surface impurities, drying in 120 deg.C blast drying oven for 24 hr, crushing, and sieving with 60 mesh sieve to obtain corn stalk powder. Soaking in phosphoric acid solution at a certain solid-to-liquid ratio, standing overnight, taking out the soaked material, charring and activating in a microwave oven, washing the obtained activated carbon with deionized water to obtain activated carbon with pH value close to 7, oven drying, and grinding with 12 mesh sieve to obtain the final product. Preferably, the volume fraction of the phosphoric acid is 57.25%, the liquid-material ratio is 20: 1(ml/g), the impregnation time is 18 hours, the microwave time is 8min, and the activated carbon prepared under the conditions has better adsorption performance.

As the volume fraction of phosphoric acid is increased, the dissolution of straw fiber molecules is more and more sufficient, but when the volume fraction of phosphoric acid reaches about 60%, the corn straw is corroded instead, so that the optimal volume fraction of phosphoric acid is 57.25%. Along with the increase of the liquid-material ratio, the iodine absorption value of the activated carbon firstly rises and then falls, and when the liquid-material ratio is 20: the iodine adsorption value is the largest at 1ml/g, the soaking amount of phosphoric acid is larger and heat release is started at the moment, the activation degree of the corn straws is the most sufficient, and the optimal liquid-material ratio is 20: 1 (ml/g). When the dipping time is 18h, the iodine absorption value is maximum, and the corn straw powder is corroded after the time is continuously increased, so that the dipping time is set to 18 h. Along with the extension of the microwave radiation time, the iodine adsorption value of the activated carbon is in a rising trend, the phosphoric acid carbon skeleton on the activated carbon is subjected to oxidation reaction, generated gas is discharged, pores of a plurality of micropores are enlarged, larger pores are formed, the iodine adsorption value is maximum when the microwave time is 8min, and the optimal microwave time is 8 min.

The animal manure is one or a mixture of more of completely decomposed cow manure, sheep manure and chicken manure.

The nitrification inhibitor is one or more of dimethylpyrazole phosphate (DMPP) and dicyandiamide (DCD). The nitrification inhibitor can affect the conversion of nitrogen in soil, intervenes the biochemical conversion process of the nitrogen by adding the nitrification inhibitor, slows down the nitrification process, and has obvious effect on reducing the leaching of nitrate and the emission of nitrogen oxide. The nitrification inhibitor and other components of the soil conditioner are applied to the soil together, and the synergistic effect improves the utilization rate of the other components in the conditioner and greatly reduces the residue of nitrate nitrogen in the soil.

A soil conditioner for reducing nitrate nitrogen residue in soil of a facility vegetable field is prepared by the following steps:

(1) stirring and mixing the main raw materials except the EM stock solution according to the weight part ratio, spraying the activated EM microbial inoculum while stirring, and adjusting the water content of the materials to be 45-55%;

(2) covering the material obtained by mixing in the step (1) with a plastic film, uncovering the film and ventilating once a day, turning the pile and adding water once on the 10 th day, and finishing fermentation after 10 days after turning the pile and adding water;

(3) drying the fermented material at a temperature lower than 30 ℃ until the water content is 5%, then crushing and sieving, and placing the preliminarily molded particles into a ball polishing machine for molding treatment.

Has the advantages that: the soil conditioner of the invention has the soil improvement effect mainly in 4 aspects:

(1) physical properties of the improved soil: the pH value of the soil is reduced, the porosity of the soil is increased, the permeability is improved, and the water storage and moisture conservation capacity is enhanced. The fly ash has good adsorption capacity on nitrogen, is rich in metal ions such as Na, Ca, Sr, Ba, K, Mg and the like, reduces the content of clay particles in soil, increases the content of sand particles, reduces the volume weight of the soil, increases the porosity and reduces the expansion rate.

(2) Optimizing the chemical properties of the soil: effectively reduces the redundant nitrate nitrogen residue in the soil and increases various trace nutrient elements required by the soil. The zeolite is a natural soil conditioner and a buffering agent for balancing soil nutrients, contains a large amount of nutrient elements and trace elements, can improve the exchange amount of soil base, promotes the formation of granular structures, can improve the utilization rate of N after being mixed with urea, and prolongs the fertilizer supply time of soil. The corn stalk carbon prepared by processing the corn stalk can prevent the residual nitrate nitrogen in the soil from polluting underground water along with the massive loss of runoff, contains organic nitrogen, phosphorus, potassium and medium trace elements, can effectively improve the soil and create a good soil environment for the growth of crops. The animal waste contains a large amount of effective nitrogen, phosphorus and potassium compounds which can be absorbed by crops, and can be processed to synthesize new high molecular organic matter humus, so that the activity of the soil is effectively improved.

(3) Improving the microbial environment of soil: EM is a novel beneficial microbial preparation which is prepared by compositely culturing more than 80 microorganisms of 10 genera such as lactic acid bacteria, saccharomycetes, actinomycetes and photosynthetic bacteria and is developed by professor Bijia photofu of university of Youki, Japan. Has the characteristics of complex composition, stable structure, wide function, no toxic or harmful chemical substances, no environmental pollution and the like. According to the invention, the content of soil microorganisms is increased by adding the activated EM microbial inoculum, so that the activity of the soil microorganisms is facilitated, especially the composition of a plant root microorganism system is rich, and the soil bioactivity and the buffering capacity are improved; the secretion of a large amount of microorganisms contains vitamins, plant growth hormone and the like, and the growth and photosynthesis of plants are greatly promoted.

(4) Is beneficial to agricultural sustainable development: while repairing soil, the method realizes the secondary utilization of solid wastes such as corn straws, livestock and poultry manure, fly ash and the like, and greatly reduces the pressure of agricultural environment.

(5) Convenient implementation, simple operation method, easily-obtained raw materials and low cost.

In conclusion, the invention adds nutrient elements and nutrient coordination substances required by soil, effectively reduces redundant nitrate nitrogen residues in the soil, achieves the dual functions of purifying the soil and increasing the fertilizer efficiency, does not bring secondary pollution after the product is applied, and can also purify the agricultural production environment and increase the sustainable capability of the soil in facilities. And the secondary utilization of solid wastes such as straws, livestock manure, fly ash and the like is realized, and the method has important significance for sustainable development of agriculture.

Detailed Description

The present invention will be described in detail with reference to specific examples below:

dimethylpyrazolophos (DMPP) is purchased from Jiujiang Woxin chemical Co., Ltd, and the product number is 3, 4-dimethylpyrazole phosphate; dicyandiamide (DCD) was purchased from the south of the river, eastern ocean chemical products, ltd.

Urea was purchased from Chongqing Zhi Chuang chemical Co.

The EM stock solution is purchased from Nanjing Ergle environmental protection biotechnology Limited and is named as EM.1. The EM stock solution is a composite culture viable bacterium product of various beneficial microorganisms mainly comprising lactic acid bacteria, saccharomycetes and photosynthetic bacteria. The EM stock solution needs to be processed into an active solution for use (the EM & 1 instruction is marked), and the method comprises the following steps: taking a piece of molasses of 10cm multiplied by 10cm, slowly adding a small amount of warm water of 40 ℃, continuously stirring until the molasses is melted, and preparing the molasses diluted aqueous solution according to the proportion of 1: 100; pouring the EM stock solution into 100 times of molasses diluent water solution, and fully and uniformly mixing; and sealing the obtained product by using a plastic film for 24 hours to obtain the activated EM microbial inoculum.

The raw materials for the soil conditioners of examples 1-4 are shown in table 1, where the parts stated in the table are parts by weight:

	example 1	Example 2	Example 3
				Corn stalk charcoal	75 portions of	70 portions of	80 portions
Zeolite	23 portions of	20 portions of	25 portions of
				Fly ash	20 portions of	15 portions of	25 portions of
Animal waste	20 portions of	15 portions of	25 portions of
				EM stock solution	20 portions of	15 portions of	25 portions of
Nitrification inhibitors	13 portions of	10 portions of	15 portions of
				Urea	8 portions of	5 portions of	10 portions of

The preparation method comprises the following steps:

(1) peeling the dried corn straws, washing impurities on the surface of the corn straws with deionized water, drying the corn straws for 24 hours in a blast drying oven at 120 ℃, crushing the corn straws and sieving the corn straws with a 60-mesh sieve to prepare the corn straw powder. Soaking in phosphoric acid solution with volume fraction of 57.25% at a solid-to-liquid ratio of 20: 1(ml/g) for 18h, taking out the fully soaked raw materials, sending into a microwave oven for carbonization and activation for 8min, washing the prepared activated carbon with deionized water to obtain excessive activated phosphoric acid with pH value close to 7, drying, and grinding with 12-mesh sieve to obtain the corn stalk carbon.

(2) And the zeolite and the fly ash are sieved by a standard sieve with 100 meshes.

(3) Taking a piece of molasses, slowly adding a small amount of warm water at 40 ℃, continuously stirring until the molasses is melted, and preparing a molasses diluted aqueous solution according to the proportion of 1: 100; then pouring EM stock solution (the EM stock solution is a compound culture live bacteria product of various beneficial microorganisms mainly comprising lactic acid bacteria, saccharomycetes and photosynthetic bacteria) into 100 times of molasses diluent water solution, and fully and uniformly mixing; and sealing the obtained product by using a plastic film for 24 hours to obtain the activated EM microbial inoculum.

(4) And stirring and mixing the main raw materials except the EM stock solution according to the weight part ratio, spraying the activated EM microbial inoculum obtained by the treatment while stirring, and adjusting the water content of the materials to be 45-55%.

(5) Covering the materials with a plastic film, uncovering the film once a day, ventilating, turning over the pile once on the 10 th day, adding water, turning over the pile, and completing fermentation for 10 days; drying the fermented material at a temperature lower than 30 ℃ until the water content is 5%, then crushing and sieving, and placing the preliminarily molded particles into a ball throwing machine for molding treatment to obtain the soil conditioner.

Example 4 Performance test

Firstly, site selection: the research field test is carried out in the science and technology (118 degrees 46 '47' E, 31 degrees 43 '36' N) of Yangtze district of Jiangning city in 2019 and 3 months, belongs to the wet climate zone of northern subtropics, has the average rainfall time of 117d for many years, the average rainfall capacity of 1106.5mm for many years, the relative humidity of 76 percent, the average annual temperature of 15.4C and the frost-free period of 237d, and is the plum rain season from the late 6 months to the early 7 months every year. The soil texture in the area is yellow brown soil. The test is carried out in a plastic greenhouse, tomatoes are continuously planted in the greenhouse for more than 10a due to shortage of land resources and breeding requirements, and the nitrate nitrogen residue condition is very serious.

II, grouping:

comparative example 1: organic fertilizer, chemical fertilizer and soil conditioner are not applied. And planting the tomatoes, irrigating once every 10 days, collecting a leaching water sample after each irrigation, and refrigerating for use after marking.

Comparative example 2: the total application amount of commercial chicken manure organic fertilizer for planting tomatoes is 10t/hm²The urea content is 750kg/hm²Is divided into3 applications, respectively 450kg/hm of basal application²In combination with the cultivation of the soil, 150kg/hm of soil is put in holes every 20 days²As an additional fertilizer for 2 times. Irrigating once every 10 days, collecting eluviated water samples after each irrigation, and refrigerating for use after marking.

Experimental groups: planting tomatoes by using the soil conditioner of the examples 1, 2 and 3 in an amount of 750kg/hm²The application is divided into 3 times, and is respectively 450kg/hm of basal application²Uniformly spreading the mixture on the surface of soil in combination with soil turning application to uniformly mix the mixture with the soil, wherein the depth of the mixture is 0-20 cm, and the mixture is respectively subjected to hole application of 150kg/hm every 20 days²As an additional fertilizer for 2 times. Irrigating once every 10 days, collecting eluviated water samples after each irrigation, and refrigerating for use after marking.

Thirdly, a test method: a leaching tank with the length of 1.5m, the width of 0.8m and the height of 0.9m is dug in the middle of each experimental plot by adopting a field in-situ seepage pool method, and a cylindrical tank with the diameter of 0.4m and the depth of 0.35m is dug in the middle of the bottom of the leaching tank and is placed in a collection barrel. In the excavation process of the leaching tank, 4 levels of soil of 0-20 cm, 20-40 cm, 40-60 cm and 60-90 cm are separately placed and backfilled according to the original levels. The underground collecting barrel is provided with two holes, a PVC pipe is respectively penetrated into the two holes to be communicated with the ground, one pipe is used for ventilation, and the other pipe is used for connecting a leaching water collecting bottle and an air pump when sampling.

The results obtained after the different test treatments are shown in table 2:

TABLE 2

From the above data, it can be seen that the examples showed a significant effect compared to the control groups 1 and 2. After the soil conditioner provided by the invention is applied, the pH value of soil is obviously reduced, the porosity of the soil is increased by about 15%, and the contents of quick-acting phosphorus and quick-acting potassium are kept stable. In addition, the nitrate content in each treated tomato fruit is lower than a specified value, namely the nitrate content in the solanaceous vegetables is not higher than 600 mg/kg. Compared with the traditional fertilization, the content of nitrate nitrogen in the soil is reduced by 70 percent, and the concentration of nitrate nitrogen in the leaching water is reduced by 40 percent.

Further, the soil conditioner provided by the invention can effectively adjust the pH value of soil, increase the porosity of the soil, reduce nitrate nitrogen residues in the soil, prevent the nitrate nitrogen residues from polluting underground water through leaching, condition an unbalanced soil nutrient system and ensure the normal production of tomatoes.

Although the invention has been described in detail above with reference to a general description and specific examples, it will be apparent to one skilled in the art that modifications or improvements may be made thereto based on the invention. Accordingly, such modifications and improvements are intended to be within the scope of the invention as claimed.

Claims (5)

1. The soil conditioner for reducing the residual nitrate nitrogen in the soil of the facility vegetable field is characterized by comprising the following raw materials in parts by weight: 70-80 parts of corn stalk carbon, 20-25 parts of zeolite, 15-25 parts of fly ash, 15-25 parts of animal waste, 15-25 parts of EM stock solution, 10-15 parts of nitrification inhibitor and 5-10 parts of urea; the animal manure is one or a mixture of more of completely decomposed cow manure, sheep manure and chicken manure;

the nitrification inhibitor is dimethylpyrazole phosphate or dicyandiamide;

the EM stock solution is a composite culture viable bacterium product of various beneficial microorganisms mainly comprising lactic acid bacteria, saccharomycetes and photosynthetic bacteria.

2. The soil conditioner for reducing nitrate nitrogen residue in soil of a greenhouse vegetable field as claimed in claim 1, which is characterized by comprising the following raw materials in parts by weight: 75 parts of corn stalk carbon, 23 parts of zeolite, 20 parts of fly ash, 20 parts of animal waste, 20 parts of EM stock solution, 13 parts of nitrification inhibitor and 8 parts of urea.

3. The soil conditioner for reducing nitrate nitrogen residue in soil of greenhouse vegetable fields as claimed in claim 1, wherein the corn stalk charcoal is prepared by first peeling air-dried corn stalks, washing, drying, crushing and sieving to obtain corn stalk powder; then, soaking the corn stalks in a phosphoric acid solution according to a solid-liquid ratio of 20: 1, fully soaking, then performing microwave carbonization, cleaning to remove redundant phosphoric acid until the pH value is close to 7, drying, grinding and sieving to obtain the corn stalk charcoal.

4. The soil conditioner for reducing nitrate nitrogen residue in soil of a greenhouse vegetable field as claimed in claim 3, wherein the impregnation liquid-material ratio is 20: 1ml/g, the impregnation time is 18h, the volume fraction of phosphoric acid is 57.25%, and the microwave carbonization time is 8 min.

5. The method of preparing a soil conditioner for reducing nitrate nitrogen residue in soil of a greenhouse vegetable field as claimed in claim 1, characterized by the steps of:

(1) stirring and mixing the raw materials except the EM stock solution according to the weight part ratio, spraying the activated EM microbial inoculum obtained by the treatment while stirring, and adjusting the water content of the materials to be 45-55%;

(2) covering the material obtained by mixing in the step (1) with a plastic film, uncovering the film and ventilating once a day, turning the pile and adding water once on the 10 th day, and finishing fermentation after 10 days after turning the pile and adding water;

(3) drying the fermented material at a temperature lower than 30 ℃ until the water content is 5%, then crushing and sieving, and placing the preliminarily molded particles into a polishing machine for molding treatment.