Special controlled-release microbial fertilizer for peanuts in continuous cropping field and preparation method thereof

The disclosure relates to the technical field of agriculture planting, particularly to a special controlled-release microbial fertilizer for peanuts in a continuous cropping field and a preparation method thereof.

With the enlargement of peanut areas in China, the continuous cropping area has been rapidly increased, and reaches more than 4 million mu per year only in Shandong. The researches show that the peanut yield can be reduced by more than 10% when in continuous cropping for one year and 15-20% when in continuous cropping for two years. Allelochemicals in peanut root exudates with autotoxicity, such as cinnamic acid, lauric acid, myristic acid, palmitic acid, oleic acid, stearic acid, 2,4-di-tert-butylphenol, 2,6-di-tert-butylphenol, phthalic acid, p-hydroxybenzoic acid and 2,4-di-tolyl dldehyde, lead to reduction in nutrition synthesis and absorption capability mainly through the damage to the cell membrane, destruction of the cell structure and inhibition of the root growth, root activity and invertase activity. Imbalance of soil and rhizosphere microbial population (the number of fungi is increased significantly, the numbers of bacteria and actinomycetes are decreased significantly), decrease of soil enzyme activity decreased (soil urease, soil invertase and soil alkaline phosphatase activities, etc.), deficiency of soil nutrient elements (phosphorus, potassium, calcium and other trace elements) and exacerbation of disease and insect pests (root knot nematode, stem rot, damping off and other soil borne diseases and insect pests) are main reasons that continuous cropping obstacle occurs.

There are a variety of microbial fertilizer products on the market, many of which can effectively alleviate the adverse effects of continuous cropping on yield and quality of peanuts. However, there was no controlled-release microbial fertilizer for improving peanut continuous cropping field.

Aiming at decreased yield and reduced production of peanuts caused by continuous cropping in the prior art, the disclosure provides a special controlled-release microbial fertilizer for peanuts in a continuous cropping field.

The disclosure also provides a method for preparing a special controlled-release microbial fertilizer for peanuts in a continuous cropping field.

In order to realize the above objective, the disclosure adopts the following technical solution:

Provided a special controlled-release microbial fertilizer for peanuts in a continuous cropping field, comprising an outer layer, a middle layer and an inner layer.

The inner layer consists of active bacteria, an inorganic matters and additives, wherein the variety and contents of active bacteria are respectively as follows: 200-300 million/g of Bacillus subtilis, 100-200 million/g of Bacillus thurigniensis, 50-100 million/g of Aspergillus niger , and 50-100 million/g of streptomycete; the variety and contents of inorganic matters are respectively as follows: 5-8 parts of calcium nitrate, 1-3 parts of magnesium sulfate, 1-3 parts of zinc sulfate 35, 1-3 parts of borax, 0.5-1 part of ammonium molybdate and 1-3 parts of ferrous sulfate; 10-15 parts of sodium carboxymethyl starch and 10-20 parts of modified starch.

In the inner layer, the contents of additives are respectively as follows: 60-80 parts of fulvic acid, 15-20 parts of alginic acid and 10-12 parts of amino acid.

The middle layer is composed of 30-50 parts of urea formaldehyde powder, 15-20 parts of polyethylene glycol and 30-40 parts of natto powder.

The components and contents of the outer layer are the same as those of the compositions in the inner layer.

The outer layer also contains 10-12 parts of rice husk carbon and 8-10 parts of cellulose.

The relative molecular weight of the cellulose is 80000-100000.

A method for preparing the special controlled-release microbial fertilizer for peanuts in a continuous cropping field, comprising the following steps:

(1) adding water whose weight is three times those of sodium carboxymethyl starch and modified starch into sodium carboxymethyl starch and modified starch in the inner layer, heating to 70-80° C., evenly stirring, adding an inorganic matter, evenly stirring, cooling to room temperature, adding active bacteria and an additive, pelletizing, and drying to obtain a core inner layer; and (2) evenly mixing urea formaldehyde powder, polyethylene glycol and ⅓ weight of natto powder in the middle layer, heating to 95° C., stirring for 1 h, then adding the remaining natto powder, evenly stirring, then carrying out ultrasonic treatment for 20 min, cooling to 38° C., spraying the treated middle layer mixed solution on the surface of the core inner layer, and rapidly rotating the core inner layer in the process of spraying to obtain double-layer particles; and (3) adding water whose weight is twice times those of sodium carboxymethyl starch and modified starch in the outer layer, heating to 70-80° C., evenly stirring, adding the inorganic matter, rice husk carbon and cellulose, evenly stirring, cooling to room temperature, adding the active bacteria and the additive, spraying the above mixed solution on the surface of the double-layer particles prepared in step (2) at room temperature, and then drying the prepared particles under low temperature.

Through a three-layer structure, the controlled-release fertilizer prepared by the disclosure can realize the fertilizer efficiency period of 50-60 days, and achieves the purpose of twice releases.

Lipopeptide antibiotics produced by Bacillus subtilis are the most important antibacterial substances, which can effectively inhibit root rot and damping off; Bacillus thuringiensis can kill pests including root knot nematodes, and has specific toxic activity to lepidoptera and other arthropod larvae ( Pieris rapae, Helicoverpa armigera , and Agrotis tigris ); Aspergillus niger and Streptomyces niger can improve the activities of soil urease, soil invertase and alkaline phosphatase, increase the contents of total nitrogen, total phosphorus, total potassium, alkali hydrolyzable nitrogen, available phosphorus, available potassium and organic matters in the soil, improve soil conditions, alleviate continuous cropping obstacles, and improve the yield and quality of peanuts in the continuous cropping field.

Fulvic acid, alginic acid and chitooligosaccharide can improve soil microenvironment, promote the growth of beneficial bacteria, and provide amino acids, polysaccharides and other physiological active substances needed by microbial flora and peanut growth.

Calcium nitrate, magnesium sulfate, zinc sulfate, borax, ammonium molybdate and ferrous sulfate fully supplement trace elements needed for peanut growth.

The disclosure has the beneficial effects:

(1) After being combined with conventional organic fertilizer, the microbial fertilizer prepared by the disclosure can increase the total amount of microorganisms in the soil, increases the quantity and variety of bacteria, fungi and actinomycetes, improves the continuous cropping obstacles of peanuts, and can effectively prevent and control soil borne fungi, has the dual effects of protection and treatment, reduces the human and material resources consumption of intensive cultivation of soil, reduces the transpiration of soil and improves the soil use efficiency and productivity, and improve the yield and quality of peanuts. (2) Rice husk carbon and cellulose are added into the outer layer of the disclosure. After fertilization, the fertilizer can provide an oxygen transport effect for partial biological bacteria. On the other hand, the fertilizer can provide a carbon source during the fermentation of biological bacteria. In the process of decomposing the outer layer, a barrier can be formed for the inner layer within a certain period of time to achieve the function of water and fertilizer conservation. (3) The middle layer provided by the disclosure can form a cross-linked network structure, which has good porosity, can effectively cover the inner layer structure, has water absorption and moisture retention and slow release and controlled release, realizes the gradual release of the inner layer, has high fertilizer utilization rate, maximizes the effect of microbial agents, and is conducive to large-scale promotion.

Next, the technical solution of the disclosure will be explained and illustrated through embodiments.

The natto powder and active bacteria used in the disclosure are available on the market.