CN103772074B - A kind of long-acting dry farming special fertilizer for sweet potato and preparation method thereof - Google Patents

Abstract

The invention relates to a special fertilizer for long-acting dry-farmed sweet potatoes and a preparation method thereof. The fertilizer is granular and includes a three-layer structure, which consists of a fertilizer core, a coating coating and a water-retaining agent coating in sequence from the inside to the outside. The core of the special fertilizer for long-acting dry-farming sweet potato of the present invention contains effective ingredients such as nitrogen fertilizer, phosphorus fertilizer, potassium fertilizer and compound micro-fertilizer specially suitable for sweet potato, and the coating coating controls the speed of water entering the film and regulates the release of nutrients. The water-retaining agent coating can effectively retain soil moisture and rainwater, reduce lateral seepage runoff and water transpiration, and ensure the growth of sweet potatoes in the middle and early stages. The preparation method of the fertilizer is completed by spraying once, the process occupies less land, the equipment investment is small, the preparation process is simple, the energy consumption is small, the cost of the coating material is low, and the price of the fertilizer is greatly reduced.

Description

A kind of special fertilizer for long-acting dry farming sweet potato and preparation method thereof

technical field

The invention relates to the field of crop fertilizers and the preparation of fertilizers, in particular to a special fertilizer for long-acting dry-farmed sweet potatoes and a preparation method thereof.

Background technique

In the prior art, the special fertilizer for sweet potato is formed by mixing elemental chemical fertilizers containing nitrogen, phosphorus and potassium and micro-fertilizers according to a certain ratio. Nitrogen fertilizers used in fertilizer materials such as urea, ammonium chloride, ammonium sulfate, ammonium bicarbonate, etc., are prone to ammonia volatilization loss after application on calcareous soil. At the same time, after being converted into nitrate nitrogen by nitrifying bacteria in the soil , it is easier to leaching and loss; and the phosphorus in the fertilizer is also easier to combine with calcium, magnesium, iron and aluminum in the soil to grow insoluble precipitation; potassium is easy to be fixed by 2:1 clay minerals; not only leads to the utilization of fertilizers The rate is low, resulting in waste of resources, and the leaching and loss of nutrients in fertilizers will also lead to eutrophication of water bodies.

In order to prolong the fertilizer effect time, the existing slow-release fertilizer is to add 1.5-2.0% controlled-release additives to the fertilizer, such as Chinese patent application publication (CN1308042A), and the controlled-release additives are selected from humic acid, dicyandiamide, and hydroquinone. There are also coated controlled-release fertilizers that have a slow-release coating on the outside of the fertilizer core. The coating material is selected from polymers. For example, the Chinese patent (ZL95190939.8) applied by an American company is composed of two series The rotating drum of the urea granule sprays a layer of sulfur coating on the surface of the urea granules, and then sprays a layer of diisocyanate polymer sealant. This secondary spraying process occupies a large area, requires a large investment in equipment, and has a complicated preparation process, which affects the popularization and use of fertilizers, and pure urea particles are not suitable for application during the entire growth period of sweet potatoes. The absorption curve of fertilizers is often inconsistent.

Contents of the invention

Aiming at many defects in the prior art, the purpose of the present invention is to provide a special fertilizer for long-acting dry-farmed sweet potatoes and a preparation method thereof, which can solve the problems of easy loss of common fertilizers and reduced fertilizer efficiency caused by water shortage, etc. The invention can satisfy the fertilizer demand of sweet potatoes throughout the growth period; and solve the technical problems of high price and complicated process of the existing slow-release long-acting fertilizer.

A special fertilizer for long-acting dry-farmed sweet potatoes. The fertilizer is granular and includes a three-layer structure. From the inside to the outside, it is the fertilizer core, the coating coating and the water-retaining agent coating;

The fertilizer core accounts for 75-85% of the total weight of the fertilizer;

The coating coating accounts for 8-15% of the total weight of the fertilizer;

The water-retaining agent coating accounts for 5-10% of the total weight of the fertilizer;

1) The fertilizer core contains nitrogen fertilizer, phosphorus fertilizer, potassium fertilizer and additives, and the weight ratio of nitrogen fertilizer, phosphorus fertilizer and potassium fertilizer in the fertilizer core calculated by pure nitrogen, phosphorus pentoxide and potassium oxide is: 1:1～2:1～4 ; The nitrogen fertilizer in the fertilizer core is selected from one or more combinations of urea, ammonium nitrate and ammonium sulfate; the phosphate fertilizer is selected from one or more of ammonium phosphate, double superphosphate, monoammonium phosphate and diammonium phosphate The combination of species; the potash fertilizer is selected from one or a combination of potassium sulfate and potassium chloride. The additive in the kernel of the fertilizer is fulvic acid, urease inhibitor, light calcium carbonate and/or compound micro-fertilizer; the compound micro-fertilizer is selected from one or more of zinc sulfate, manganese sulfate, ferrous sulfate and boric acid Several combinations.

2) The coating coating contains the following components in percentage by weight of the fertilizer: 5-10% urea-formaldehyde containing 0.05-0.5% ammonium chloride and 0.01-1% thiourea, 3-5% polyethylene wax ; The nitrogen fertilizer synergist that accounts for the nitrification inhibitor type of coating coating weight 0-5% can also be contained in the coating coating, and the nitrogen fertilizer synergist is selected from dicyandiamide and 2-chloro-6-(three Chloromethyl) pyridine or a combination of two;

3) The water-retaining agent coating is a sodium polyacrylate polymer water-retaining agent.

2. a kind of method concrete steps of preparing above-mentioned long-acting dry farming sweet potato special fertilizer are as follows:

1) Prefabricated fertilizer core: put each elemental fertilizer into the stirring mixer in proportion, mix evenly, granulate, dry, and screen out the solid particles with the required particle size; drums can be used in the granulation process of the fertilizer core Steam granulation, disc granulation or spray granulation process, the core of the fertilizer is a spherical granular fertilizer with a particle size of 2.5-3.5mm; the drying temperature is 80-120°C;

2) Spray coating: Send the granulated fertilizer core into the fluidized bed coating machine, and spray the various materials of the coating coating on the surface of the fertilizer core synchronously with an atomization device, at 70-100°C Carry out curing coating processing under certain conditions;

3) The fertilizer coated in step 2) is rolled and adhered to the outer surface of the fertilizer with a sodium polyacrylate polymer water-retaining agent as a water-retaining agent coating; the special fertilizer for long-acting dry-farming sweet potatoes is obtained.

Beneficial effects: the long-acting sweet potato special fertilizer for dry farming of the present invention contains effective ingredients such as nitrogen fertilizer, phosphorus fertilizer, potassium fertilizer and compound micro-fertilizer specially suitable for sweet potato. Nitrogen, phosphorus, potassium and other macroelements and trace elements are used as elemental or compound fertilizers in an appropriate proportion. After granulation, drying and other processes are processed into fertilizer kernels, they are sprayed synchronously with a certain thickness through a drum fluidized bed process. The encapsulating coating and a layer of water-retaining agent layer. The coating coating and the water-retaining agent layer are composite coatings with slow-release water retention, which function to block water, improve the toughness of the coating layer, enhance the adhesion between the coating coating and the fertilizer core, and seal the coating Good continuity. By controlling the molar ratio of urea to formaldehyde in urea-formaldehyde, the dense water-blocking performance of urea-formaldehyde and polyethylene wax composite film can be adjusted. Control the speed of water entering the membrane and regulate the release of nutrients. The water-retaining agent coating can effectively retain soil moisture and rainwater, reduce lateral seepage runoff and water transpiration, and ensure the growth of sweet potatoes in the middle and early stages. The preparation method of the fertilizer is completed by spraying once, the process occupies less land, the equipment investment is small, the preparation process is simple, the energy consumption is small, the cost of the coating material is low, and the price of the fertilizer is greatly reduced.

The ratio of each nutrient in the long-acting dry-farming sweet potato special fertilizer of the present invention is very suitable for the needs of sweet potato growth. Since the long-acting dry-farming sweet potato special fertilizer has a controlled-release coating, its nutrient release curve is consistent with the absorption curve of the sweet potato fertilizer. , can meet the demand of sweet potato for nutrients in time, and at the same time can control the release, prevent the nutrients from being leached and fixed, and increase the fertilizer utilization rate by more than 5 percentage points. The present invention applies the special fertilizer for long-acting dry-farmed sweet potatoes when the sweet potatoes are ridged, or one-time application when the sweet potatoes are cut. Topdressing during the growth period can avoid the damage of common fertilizers to sweet potato seedlings, prevent excessive growth in the early stage, lack of fertilizer in the later stage, and especially the supply of potassium in the later stage. The fertilizer has the characteristics that one-time fertilization can meet the nutrient needs of sweet potatoes during the whole growth period. The fertilizer effect is long-term and safe. It is easy to fertilize, saves fertilizer, saves labor, improves fertilizer efficiency, and protects the environment. At the same time, it is applied in the form of seed fertilizer or hole application topdressing, which can continuously supply sweet potato nutrients during the growth period of sweet potatoes. According to the growth period of sweet potatoes, the nutrient release time can be set at 45-120 days. By reducing the amount of fertilizer, it can save fertilizer resources without requiring farmers to increase investment. It is an environmentally friendly and fool-friendly special fertilizer for sweet potatoes.

Detailed ways

Example 1

A special fertilizer for long-acting dry-farmed sweet potatoes, the specific raw materials and preparation method are as follows:

(1), prefabricated fertilizer core: 200kg of nutrient P ₂ O ₅ content of 40% powdery superphosphate, 480kg of K ₂ O content of 50% potassium sulfate, 55kg of powdery urea, 25kg of yellow rot Put the acid into the stirring mixer and mix well.

The spray granulation process is used for granulation, specifically: the uniformly mixed powdered triple superphosphate, potassium sulfate, powdered urea, and additives are fed into the granulation drum. Melt 100kg of urea, spray it into the fertilizer mixture in the granulation cylinder by spray granulation process, then dry it at 90°C and sieve it into a spherical granular fertilizer core with a particle size of 2.5-3.5mm. The weight ratios of nitrogen fertilizer, phosphorus fertilizer and potassium fertilizer in the fertilizer core calculated by pure nitrogen, phosphorus pentoxide and potassium oxide are: 8.3-9.5-27.9.

(2) Spray coating: send the granulated fertilizer core into the fluidized bed coating machine, the temperature is controlled at 100°C, and the urea formaldehyde containing 0.5% ammonium chloride and 1% thiourea is sprayed with an atomizing device Solution 60kg and 30kg of polyethylene wax are sprayed on the surface of the fertilizer core synchronously;

(3) Finally, stick 50kg of sodium polyacrylate water retaining agent on the outer surface of the fertilizer by rolling. After the coating is processed, it is a special fertilizer for long-term dry farming sweet potatoes.

For the fertilizer prepared by the above method, the weight of the coating coating and the water-retaining agent coating accounts for 14% of the total weight of the fertilizer, and the slow-release period is 90 days.

In the case that the process and materials are exactly the same as those mentioned above in this example, replace the materials in step (2) with 93kg of urea-formaldehyde solution containing 0.5% ammonium chloride and 1% thiourea and 40kg of polyethylene wax to prepare The weight of the coating coating and the water-retaining agent coating in the fertilizer accounted for 17.6% of the total weight of the fertilizer, and the slow-release period was 120 days.

This kind of long-acting special fertilizer for dry-farming sweet potatoes is suitable for the dry and thin soil in the northern hilly area.

Example 2:

The special fertilizer for long-acting dry-farming sweet potato containing trace element zinc can be prepared by the following steps.

(1) Prefabricated fertilizer core: 50kg of powdered urea, 110kg of powdered monoammonium phosphate with a nutrient content of NP ₂ O ₅ -K ₂ O of 12-55-0, and 480 kg of potassium sulfate with a K ₂ O content of 50% , 42kg of zinc sulfate with a zinc content of 24%, and 38kg of fulvic acid are mixed evenly. The above-mentioned fertilizers that have been mixed evenly are sent into the granulation drum.

Melt 140kg of urea, and use the spray granulation process to spray all the melted 140kg of urea into the fertilizer mixture in the granulation tube, and control to achieve a suitable particle size, which is a special fertilizer for sweet potatoes with a nutrient content of 11.7-7-27.9 (Also contains 1% trace element zinc). The granulation process can also adopt drum steam granulation or disc granulation. In the drying process, the drying and granulation temperature of the drying kiln is 100°C. In the screening process, the inner core is a spherical granular fertilizer with a particle size of 2.5-3.5mm.

(2) Spray coating: Send the granulated fertilizer core into the fluidized bed coating machine, use an atomization device to spray 60kg and 30kg of urea-formaldehyde solutions containing 0.5% ammonium chloride and 1% thiourea curing agent Polyethylene wax is simultaneously sprayed on the surface of the fertilizer core;

(3) Finally, stick 50kg of sodium polyacrylate water retaining agent on the outer surface of the fertilizer by rolling. After the coating is processed, it is a special fertilizer for long-term dry farming sweet potatoes.

The composition and content of the special fertilizer for long-acting dry-farming sweet potatoes are: after the nitrogen, phosphorus, and potassium in the special fertilizer for long-acting dry-farming sweet potatoes are converted into nitrogen, phosphorus pentoxide, and potassium oxide, the weight sum of the three is the long-term dry-growing sweet potato fertilizer. 42±1% of the weight of the special fertilizer for sweet potatoes; the weight of the controlled-release film accounts for 14% of the total weight of the fertilizer, and the controlled-release period is 90 days.

In the case that the process and materials are exactly the same as those mentioned above in this example, replace the materials in step (2) with: 93kg of urea-formaldehyde solution containing 0.5% ammonium chloride and 1% thiourea curing agent and 40kg of polyethylene Wax, the weight of the coated coating and the water-retaining agent coating in the prepared fertilizer accounted for 18.3% of the total weight of the fertilizer, and the slow-release period was 120 days.

Example 3:

Under the situation that manufacturing process is identical with embodiment 1 and 2, adjust the kind and proportioning of material, the different fertilizer inner cores of making, as shown in table 1:

Table 1 Fertilizer core combination ratio selection

The additive 1 is selected from one or more mixtures of fulvic acid, urease inhibitors and light calcium carbonate; the additive 2 is a compound micro-fertilizer selected from zinc sulfate, manganese sulfate, ferrous sulfate and boric acid one or a combination of several.

On the outside of the fertilizer core, the thickness of the coating coating and the water-retaining agent layer sprayed are different, and the material ratio of the curing agent in the coating coating is different, which can produce special fertilizers with different slow-release time and water retention capacity (see Table 2 ).

Table 2 Combination ratio selection of coating coating and water-retaining agent coating materials

The curing agent is a composition of 0.05-0.5% of ammonium chloride accounting for the weight of urea-formaldehyde and 0.01-1% of thiourea accounting for the weight of urea-formaldehyde.

Claims (2)

1. a long-acting dry farming special fertilizer for sweet potato, this fertilizer is particulate state, comprises three-decker, is followed successively by fertilizer kernel, coating coating and water-holding agent coating from inside to outside; It is characterized in that:

Fertilizer kernel accounts for 75 ~ 85% of fertilizer gross weight;

Coating coating accounts for fertilizer gross weight: 8 ~ 15%;

Water-holding agent coating accounts for fertilizer gross weight: 5 ~ 10%;

1) contain nitrogenous fertilizer, phosphate fertilizer, potash fertilizer and additive in described fertilizer kernel, the weight ratio that in fertilizer kernel, nitrogenous fertilizer, phosphate fertilizer and potash fertilizer calculate with purity nitrogen, Vanadium Pentoxide in FLAKES and potassium oxide is respectively: 1: 1 ~ 2: 1 ~ 4; In described fertilizer kernel, nitrogenous fertilizer is selected from the combination of one or more in urea, ammonium nitrate and ammonium sulfate; Phosphate fertilizer is selected from the combination of one or more in ammonium phosphate, double superhosphate, monoammonium phosphate and diammonium phosphate; Potash fertilizer is selected from one or both combination of potassium sulfate and Repone K; Additive in described fertilizer kernel is xanthohumic acid, urease inhibitor, light calcium carbonate and/or compound trace element fertilizer; Described compound trace element fertilizer is selected from the combination of one or more in zinc sulfate, manganous sulfate, ferrous sulfate and boric acid;

2) described coating coating contains the following one-tenth accounting for weight of fertilizer per-cent and is grouped into: 5-10% containing 0.05-0.5% ammonium chloride and the urea formaldehyde of 0.01-1% thiocarbamide, the polyethylene wax of 3-5%; Containing the nitrogen fertilizer potentiating agent of nitrification inhibitor type accounting for coating coating wt 0-5% in coating coating, described nitrogen fertilizer potentiating agent is selected from one or both the combination in Dyhard RU 100 and the chloro-6-of 2-(trichloromethyl) pyridine;

3) described water-holding agent coating is sodium polyacrylate polymer water-holding agent.

2. prepare a method for long-acting dry farming special fertilizer for sweet potato as claimed in claim 1, it is characterized in that concrete steps are as follows:

1), prefabricated fertilizer kernel: each straight fertilizer is dropped in stirring mixer in proportion, mixes, granulation, dry, sieve out the solid particulate needing size; Rotary drum steam granulation, disc granulation or spray granulating technique is adopted, the ball-shaped granular fertilizers of fertilizer kernel to be particle diameter be 2.5-3.5mm in the granulating working procedure of fertilizer kernel; Bake out temperature is 80-120 DEG C;

2), spraying coating: the fertilizer kernel completing granulation is sent in fluidized-bed film applicator, with atomisation unit, the various synchronous material of coating coating is sprayed at the surface of fertilizer kernel, be cured coating processing under 70-100 DEG C of condition;

3), by step 2) fertilizer after coating, adhere to sodium polyacrylate polymer water-holding agent as water-holding agent coating at the superficies of fertilizer by rolling; Namely long-acting dry farming special fertilizer for sweet potato is obtained.