CN102603398B - Slow release fertilizer and preparation method thereof - Google Patents

Abstract

The invention discloses a slow-release fertilizer containing attapulgite and a preparation method thereof. Each fertilizer granule of the slow-release fertilizer granule of the present invention is a layered structure of at least two layers, and its core and its outer layers are made of various fertilizers mixed in a certain proportion, with an attapulgite soil layer between each fertilizer layer apart. The present invention provides two examples of slow-release fertilizers suitable for corn and potato respectively. The preparation method of the slow-release fertilizer granule of the present invention is: first crush each component fertilizer into powder, then weigh various fertilizer powders in the inner layer of the core according to a predetermined weight and sprinkle water as a binder for granulation. After part of the fertilizer is formed, a certain amount of attapulgite is put into it, and watering is continued, so that attapulgite is evenly wrapped on the outside of the fertilizer granules, and the aforementioned process is repeated to form the fertilizer layers and wrapping layers of the slow-release fertilizer granules layer by layer.

Description

A kind of slow-release fertilizer and preparation method thereof

technical field

The present invention relates to a fertilizer and a preparation method of the fertilizer. Specifically, the present invention relates to a slow-release fertilizer and a preparation method of the fertilizer, especially a fertilizer containing attapulgite. the

Background technique

Fertilizers can promote the growth of crops, and it is common knowledge to apply fertilizers in crop cultivation. The practice of agricultural production shows that due to the comprehensive influence of fertilizer properties and soil environmental conditions, low fertilizer use efficiency is a common problem in the use of chemical fertilizers. At present, the seasonal utilization rate of chemical fertilizers in my country is relatively low: nitrogen is 30% to 35%, phosphorus is 10% to 20%, and potassium is 30% to 35%. Ordinary chemical fertilizers are prone to deliquescence and caking, coupled with decomposition, leaching, and volatilization, resulting in very serious nutrient loss. In order to make the fertilizer release for a long time, in the prior art, attapulgite is often added to the fertilizer so that the fertilizer can be released slowly. Attapulgite clay (attapulgite) is a kind of natural non-metallic clay mineral, which is widely distributed and has large reserves in my country. It has the following characteristics: light specific gravity (2.0～2.3g/cm ³ ); PH=8.5±1; viscous and plastic when wet, small drying shrinkage, and no cracks; strong water absorption, which can reach more than 150%; Internal porous channel, large specific surface, up to 500m ² /g or more; stable electrochemical performance, not easily flocculated by electrolyte, good stability in high temperature and salt water. The above characteristics determine that attapulgite is an ideal coating material. A variety of slow-release fertilizers using attapulgite as the coating material are disclosed in Chinese patents, such as: 201110181781.5, 200710302509.1, 200810099402.6, etc. Slow-release fertilizer is to coat the surface of fertilizer particles with a thin layer of hydrophobic substances to make coated fertilizers, which can greatly improve the utilization rate of fertilizers. However, due to the shortcomings of the current slow-release fertilizers in the aspects of complex production process, high cost, and some coating materials are not friendly to the environment, the widespread use of these fertilizers in field crops is limited. Secondly, the slow-release fertilizers in the prior art are prepared by uniformly mixing the fertilizer and attapulgite.

In recent years, the technology of soil testing and formula fertilization has been widely promoted in my country. Soil testing and formula fertilization technology refers to analyzing the soil nutrient content of cultivated land through laboratory tests, grasping and understanding the soil fertility status in time, and according to the law of fertilizer needs of different crops and agricultural production requirements, under the guidance of agricultural technicians, the appropriate proportion of different nutrients is balanced. Fertilization is a scientific fertilization method that improves the utilization rate of fertilizer nutrients and promotes high-yield, high-efficiency, and high-quality agricultural production. the

Related studies have also shown that plants have different needs for different nutrients in different growth stages, but the existing slow-release fertilizers prepared by uniform mixing cannot meet the needs of plants in different growth stages for different nutrients, which also Cause the problem that existing fertilizer use efficiency is not high. the

For this reason, look for a kind of fertilizer that can adapt to the fertilizer demand of plants in different growth stages prepared with efficient, cheap natural and semi-natural materials, and one of the development directions of the preparation method of this fertilizer. the

Since 2005, my country has started the promotion of soil testing and formulated fertilization. The special slow-release fertilizer plays a very important role in this project because its nutrient release can meet the crop nutrient demand curve and can realize one-time fertilization. If the slow and controlled release fertilizer with the advantages of one-time fertilization can be combined with the promotion of soil testing and formula fertilization, it will undoubtedly be a rare historical opportunity for the promotion of this new type of fertilizer. the

Contents of the invention

The invention provides a fertilizer granule prepared from high-efficiency and cheap natural and semi-natural materials, which can meet the fertilizer requirements of plants in different growth stages and has a slow-release effect, and a preparation method of the fertilizer granule. the

Each fertilizer granule of the slow-release fertilizer granule of the present invention is a layered structure of at least two layers, and its core and its outer layers are made of various fertilizers mixed in a certain proportion, with an attapulgite soil layer between each fertilizer layer apart. the

The slow-release fertilizer granule of the present invention is preferably three layers, and the inner layer of its outermost layer, middle layer and core determines the ratio and quantity of different fertilizers according to the fertilizers needed for the seedling stage, growth stage and maturity stage of the plant respectively. the

As an embodiment of the present invention, a kind of nitrogen fertilizer used in the slow-release fertilizer grain that is applicable to corn is urea, and the phosphorus fertilizer used is superphosphate, and the relative weight ratio of nitrogen in each layer, phosphorus fertilizer is respectively: outer layer= 2.13～5.73: 0.25～0.57; Middle layer = 48.31～130.37: 14.35～32.53; Inner layer at the core = 43.78～118.13: 7.89～17.88; The weight of the attapulgite soil layer between the fertilizer layers is: outer layer = 0.60～ 2.70; middle layer = 15.67-41.22; inner layer = 12.92-58.29. the

As an embodiment of the present invention, a kind of nitrogen fertilizer used in the slow-release fertilizer granule that is applicable to potato is urea, and the phosphate fertilizer used is superphosphate, and the potash fertilizer used is potassium sulfate, and the nitrogen in each layer, phosphorus, potash fertilizer The weight ratios are: outer layer = 5.67～13.4: 0.36～1.92: 0～7.29; middle layer = 35.89～84.89: 14.35～32.53: 0～29.15; inner layer at the core = 52.89～125.1: 2.61～13.91:0～ 44.53; the weights of the attapulgite soil layers between the fertilizer layers are: outer layer = 1.51-9.69; middle layer = 9.36-52.37; inner layer = 13.88-78.66. the

The preparation method of any slow-release fertilizer granule according to the present invention is: first pulverize urea, superphosphate powder or potassium sulfate into a powder with a diameter less than or equal to 1mm, and weigh the various components of the core inner layer according to a predetermined weight. Fertilizer powder is sprinkled with water as a binder for granulation. After most of the fertilizer is formed, a certain amount of attapulgite is put into it, and watering is continued, so that attapulgite is evenly wrapped on the outside of the fertilizer granules to form the inner layer of the slow-release fertilizer granules; Put in a certain amount of fertilizer in the middle layer, sprinkle water to make it evenly wrap around the round granules of the inner slow-release fertilizer, then add a certain amount of attapulgite, sprinkle water to make it continue to wrap around the granules, and form slow-release fertilizer granules layer by layer Each fertilizer layer and wrapping layer. the

The preparation method of the fertilizer granules of the invention is simple, the effect is reliable, the cost is low, and the whole treatment process is pollution-free. The fertilizer obtained by the invention has very good slow-release property, and can have better effect than the slow-release fertilizer prepared by the prior art. the

Description of drawings

Accompanying drawing 1 is the cross-sectional schematic diagram of a slow-release fertilizer grain r of the present invention, and wherein 1 is the inner layer positioned at the core, 2 is the middle layer, and 3 is the outer layer, and the black band between each layer among the figure is for separating each layer The wrapping layer of attapulgite. the

Figure 2 shows the change of soil inorganic nitrogen in corn field. the

Figure 3 shows the change of soil available phosphorus in corn field

Figure 4 shows the change of inorganic nitrogen in potato field soil. the

Figure 5 shows the change of available phosphorus in potato field soil. the

Figures 6 to 8 show the changes in the inorganic nitrogen content of potato leaves under three fertilization gradients. the

Detailed ways

The present invention provides the following examples. One embodiment provides a slow release fertilizer granule suitable for corn, and another embodiment provides a slow release fertilizer granule suitable for potato. the

Embodiment 1 is applicable to the slow-release fertilizer grain of corn

The planting area determined in this example is the Zhonglianchuan area in Yuzhong, Gansu, which is a typical rain-fed agricultural area on the Loess Plateau, and the main food crops in this area are corn and potatoes. Agricultural development is limited due to poor production conditions in the region due to limited precipitation and low soil fertility. In production practice, many farmers do not understand the nutritional characteristics, fertilizer requirements, and fertilization methods of corn and potatoes. Fertilization is carried out according to traditional fertilization methods, and the nutrient utilization rate is low, which leads to defertilization of corn and potatoes in the late growth period, which seriously affects the yield. improve. the

1. Determination of fertilization amount by soil testing for corn

1.1 Determine the amount of fertilizer required according to the target output

The target yield is how much corn should be planted in the current year. The average local corn yield is about 375kg per mu. For comparison, we will increase and decrease 20% on this basis, and then determine the two target yields of 450kg per mu and 300kg per mu. . Generally, for every 100kg of corn produced, corn needs to absorb 2.5kg of pure nitrogen, 1.2kg of phosphorus pentoxide, and 2.0kg of potassium oxide from the soil. The ratio of nitrogen, phosphorus, and potassium is: 1:0.48:0.8. Taking the target yield of 450kg/mu as an example, the pure nitrogen required for the whole growth period of corn is 450kg/mu×2.5/100=11.25kg/mu, and the required phosphorus pentoxide is 450kg/mu×1.2/100=5.4kg/mu , Potassium oxide is 450kg/mu×2/100=9kg/mu. the

1.2 Calculation of soil nutrient supply

Soil nutrient supply (kg/mu) = soil test value (mg/kg) x 0.15 x correction factor (1) 

According to the situation in Yuzhong area, the correction factor for nitrogen is 0.5, phosphorus is 0.5, and potassium is 0.8. Through laboratory tests, the average value of soil alkaline hydrolysis nitrogen in this area is 71mg/kg, available phosphorus is 30.04mg/kg, and available potassium is 135mg/kg. Then the region:

Alkaline hydrolysis nitrogen supply (kg/mu)=71mg/kg×0.15×0.5=5.325kg/mu. the

Available phosphorus supply (kg/mu) = 30.04mg/kg×0.15×0.5=2.253kg/mu. the

Available phosphorus supply (kg/mu) = 135mg/kg×0.15×0.8=16.2kg/mu. the

1.3 Determination of corn fertilization amount

Fertilizer application amount (kg) = total amount of nutrients required for target output (kg) - total amount of soil nutrient supply (kg) / fertilizer utilization rate for the current season (%) (2)

Seasonal utilization rate of nitrogen, phosphorus and potassium fertilizers: nitrogen 30%-35%, phosphorus 10%-20%, potassium 40%-50%. Calculated according to (2), the per unit yield of corn is 450kg/mu, and the required:

Pure nitrogen (N)=(11.25-5.325)/0.35=16.9kg/mu. the

Phosphorus pentoxide (P ₂ O ₅ )=(5.4-2.253)/0.2=15.735 (kg/mu). Considering the obvious aftereffect of phosphorus fertilizer, the application of phosphorus fertilizer can be halved, that is, 7.87 (kg/mu).

Potassium oxide (K ₂ O) = (9-16.2)/0.50 = -14.4 (kg/mu), the result is a negative value, so corn does not need potassium fertilizer in this area.

Calculated by the above method, when the yield of corn per mu is 300 kg, 6.3 kg of nitrogen and 1.5 kg of phosphorus are needed per mu of land; when the yield of corn per mu is 450 kg, 16.9 kg of nitrogen and 3.4 kg of phosphorus are needed per mu of land. When the yield per mu of corn is the local average yield (375 kg), fertilize according to the customary amount of local farmers, that is, apply 9.3 kg of nitrogen and 2.6 kg of phosphorus per mu of land. Because the soil has a strong potassium supply capacity, no additional potassium fertilizer is needed. the

1.4 The specific distribution of nutrients in the growth period of corn

Corn absorbs 2.5% nitrogen, 1.12% available phosphorus and 3% available potassium at the seedling stage; 51.15% nitrogen, 63.81% available phosphorus, and 97% available potassium during the growth period; 46.35% nitrogen, 35.07% available phosphorus, and available potassium at the mature stage 0%. the

Taking the distribution of nitrogen as an example, when the yield of corn is 450kg/mu, the amount of nitrogen applied at the seedling stage is 16.9kg/mu×2.5%=0.42kg/mu; the amount of nitrogen applied during the growth period is 16.9kg/mu×51.15%=8.65kg/ mu; the amount of nitrogen applied in the mature stage is 16.9kg/mu×46.35%=7.83kg/mu. the

The specific allocation and calculation methods of other nutrients are the same as above. the

1.5 Determination of the amount of corn commercial fertilizer

The test fertilizers _{are: commercially available urea (containing N46.4%), superphosphate (containing P2O516 %} ).

Amount of commercial fertilizer (kg/mu) = pure nutrient amount/nutrient content of fertilizer used (%)

Taking the amount of urea as an example, when the per unit yield of corn is 450kg/mu, the amount of urea used in the seedling stage is 0.42kg/mu/0.46=0.91(kg/mu), and the amount of urea used in the growth period is 8.65kg/mu/0.46=18.8(kg/mu) , the amount of urea in the mature stage is 7.83kg/mu/0.46=17.02 (kg/mu). the

On the basis of the above and with reference to the amount of soil used in the attapulgite slow-release fertilizer in the prior art, the proportioning of each layer of fertilizer granules and the amount of attapulgite used in the present embodiment have been determined, see Table 1 and Table 2., The formulas in Table 1 and Table 2 are taken by weighing each component to make corn layered ring-wrapped slow-release fertilizer (PCF stands for layered ring-wrapped slow-release fertilizer, and 20% represents that the weight of each layer of ring-wrapped attapulgite accounts for the unevenness of the layer and the corresponding package. 20% of the total weight of the barbed soil layer, 30% represents that the weight of the attapulgite barbed soil surrounding each layer accounts for 30% of the total weight of the layer and the corresponding wrapped attapulgite barbed soil layer, 1, 2, and 3 represent 300kg/mu respectively, 375kg/mu and 450kg/mu three different target yields). the

Table 1 corn layered ring package slow release fertilizer formula (20% PCF)

Table 2 corn layered ring package slow-release fertilizer formula (30% PCF)

Table 3 and Table 4 respectively provide the attapulgite slow-release fertilizers prepared according to the prior art, and Table 5 provides the formulas of direct fertilization commonly used by farmers in the test area for comparison. Wherein in Table 3 and Table 4, 20% and 30% of attapulgite weight account for 20% and 30% of the total weight of attapulgite and used fertilizer respectively. the

Table 3 corn attapulgite mixed control formula (20%PMF)

Table 4 Corn Attapulgite Mixed Control Formula (30%PMF)

Table 5 Corn Fertilizer Control Formula (CF)

The concrete preparation steps of slow-release fertilizer granules of the present invention are as follows:

1. Put urea, superphosphate, and potassium sulfate into a pulverizer and crush them into powders with a diameter less than or equal to 1mm. the

2. According to the pre-calculated amount, take various fertilizer powders required in the maturity stage and put them into the open rotary disc granulator. While stirring the fertilizer, sprinkle water as a binder for granulation. After most of the fertilizer is formed, put in the corresponding proportion of attapulgite and continue to sprinkle water so that the attapulgite is evenly wrapped on the outside of the fertilizer granules to form the inner layer of slow-release fertilizer. The granulation in this embodiment adopts an open rotary disc granulator. The device is mainly composed of a rotatable disc and an adjustable height baffle. The material will form a round granular shape when it continuously moves in a circular motion in the disc. Adjust the baffle. The height of the plate can control the diameter of the pellets, and the particle size can be controlled by properly adjusting the height of the baffle during the granulation process. the

3. Continue to put the fertilizer needed in the growth period into the turntable, sprinkle water to make it evenly wrapped outside the round granules of the inner slow-release fertilizer, add the corresponding proportion of attapulgite, and sprinkle water to make it continue to wrap around the granules to form a slow-release fertilizer the middle layer. the

4. Finally, put in the fertilizer needed at the seedling stage, sprinkle water to make it evenly wrapped outside the round grains of the slow-release fertilizer in the middle layer, add a corresponding proportion of attapulgite, and sprinkle water to make it continue to wrap around the grains to form the outer layer of the slow-release fertilizer. Thus, the attapulgite layered ring-wrapped slow-release fertilizer is obtained. After sieving, the particles with a diameter of 0.2-0.5 cm are used as test particles. Can prepare its profile as described in accompanying drawing 1 fertilizer granule through above-mentioned treatment. the

Due to the special physical properties of attapulgite, the granulation process only uses pure water as a binder, and no other binders and excipients are needed. the

The fertilizers in Table 4 and Table 5 are granulated according to the prior art, that is, the attapulgite and the fertilizer are evenly stirred before being granulated. the

In order to verify the effect of the fertilizer, the inventor designed field experiments in 2010 and 2011, summarized as follows:

1. Overview of the experimental site

The experimental site is located in Zhonglianchuan area of Yuzhong (36°02'N, 104°25'E, 2400 meters above sea level), with an average annual rainfall of 320mm, and about 56% of the rainfall occurs from July to September, and there is no groundwater source. The annual average free water evaporation is 1300mm. The area is followed by a semi-arid climate in the middle temperate zone, with an annual average temperature of 6.5°C. The test field is a beach, the soil is black hemp soil (FAO taxonomy), the average soil bulk density of 0-200cm is 1.27g/cm ³ , and the pH value is about 8.5.

2. Experimental design

In the 2010 corn field experiment, 20% PCF, 30% PCF, 20% PMF, and CF were used. There were 12 treatments, 3 repetitions, random arrangement, and an area of 18 square meters. In the corn field experiment in 2011, 30% PCF, 30% PMF, and CF fertilizers were used. There were 9 treatments in total, 3 repetitions, arranged randomly, and the area of the plot was 22 square meters. the

The two-year maize experiments were planted in double ridges and fully filmed in furrows. The tested variety was Jiudan No. 3, and 37,500 seedlings were preserved per hectare of land. In view of the severe spring drought in the local area, the experimental field is plowed in time after the soil surface is thawed in the middle and late March every year, and the above-mentioned fertilizers are applied at one time in combination with the plowing. No topdressing is required during the growth period, and the film is immediately covered, and the seeds are sown in late April. , harvested in early October. the

The test material, attapulgite soil, is produced from raw ore in Linze County, Gansu Province, and the processing specification is 120 mesh. The tested fertilizers are commercially available urea ( _containing N46.4%), superphosphate (containing _P2O5 16%), and potassium sulfate (containing _K2O52 %).

In addition to the above-mentioned attapulgite layered ring-packed slow-release fertilizer, two treatments are also designed for comparison: manufacture PMF according to the formula of table 3 and table 4 (no layering, all fertilizers are directly mixed with attapulgite, and 20% represents attapulgite The stick clay weight accounts for 20% of the slow-release fertilizer gross weight, and 30% represents that the attapulgite clay weight accounts for 30% of the slow-release fertilizer gross weight), and CF is manufactured according to the formula in Table 5 (do not add attapulgite clay, and directly apply chemical fertilizers). The total amount of fertilizer and attapulgite in the above two treatments was the same as that in the PCF treatment. Both PCF and PMF are granulated by a rotary disc granulator, and CF directly uses commercially available urea (containing 46.4% of N), superphosphate (containing 16% of P ₂ O ₅ ), and potassium sulfate (containing 52% of K _{2 O} ).

In test:

Soil moisture was determined by drying method. Before sowing and after harvesting, a soil auger (4 cm in diameter) was drilled in the crop planting area and measured to a depth of 200 cm in the soil layer. the

Water use efficiency of crops: WUE=Y/ET, Y is crop yield per unit area; ET is water consumption in the same area (soil moisture change plus precipitation in the same period). the

Fertilizer partial productivity (Partial factor productivity, PFP) = yield of fertilization area/fertilization amount, this index can reflect the efficiency of fertilizer use to a certain extent. the

When the corn was harvested, 10 corn plants were randomly selected in the middle area of each plot to measure the ear length, ear diameter, ear grain number, seed yield and weigh the dried (105°C, 1h, 70°C, 72h) hundred Grain weight, straw weight and grain yield. the

4. Statistical analysis of data

After testing the normal distribution of the experimental data, ANOVA in SAS statistical analysis software was used for analysis of variance. Use Excel for graphing. the

5. Experimental results

The experimental results are shown in Table 6 to Table 8. Note: The same column contains different letters marked with significant difference at P=0.05 level, the same below. the

Table 6. Yield indicators of corn field experiments in 2010

Table 7. 2010 corn field experiment traits index

Table 8. Fertilizer use efficiency of corn field experiments in 2010

In the corn field experiment in 2010, Table 6 shows that the attapulgite layered wrapping treatment of the present invention has significantly improved grain yield, aboveground biomass and water use efficiency, compared with the control, the yield increased by 12%-26.7%. The effect of 30% attapulgite encircling treatment is better than that of 20% encircling treatment. Table 7 shows that the attapulgite layered ring-wrapping treatment of the present invention has significantly improved plant height, stem diameter, ear length, ear diameter, grain number per ear, and 100-grain weight. The effect of 30% attapulgite encircling treatment is better than that of 20% encircling treatment. Table 8 shows that the fertilizer partial productivity of nitrogen fertilizer and phosphorus fertilizer treated with attapulgite layered and surrounded by layers of the present invention has been significantly improved. The effect of 30% attapulgite encircling treatment is better than that of 20% encircling treatment. the

For the corn field experiment in 2011, Table 16 shows that the treatment of 30% attapulgite layered wrapping significantly increased grain yield, aboveground biomass and water use efficiency, and the yield increased by 9%-11% compared with the control. Table 9 shows that the treatment of 30% attapulgite layered ring wrapping has significantly improved plant height, stem diameter, ear length, ear diameter, number of grains per ear, and 100-grain weight. Table 10 shows that the fertilizer partial productivity of nitrogen fertilizer and phosphorus fertilizer under the treatment of 30% attapulgite layering and wrapping has been significantly improved. the

Table 9. 2011 corn field experiment traits index

Table 10. Fertilizer use efficiency of corn field experiments in 2011

Embodiment 2 is suitable for the slow-release fertilizer granule of potato

1. Overview of the experimental site

The land tested is the land in the same area as the previous embodiment. the

2. Experimental design and potato soil testing to determine the amount of fertilization

2.1 Determine the amount of fertilizer required according to the target output

The local average potato yield is about 1500kg per mu. For comparison, we have raised and lowered it by 17% on this basis, and then determined two target yields of 1750kg per mu and 1250kg per mu. 6kg of pure nitrogen, 2kg of phosphorus pentoxide, and 13kg of potassium oxide are required to produce 1000kg of tubers. The calculation method of nutrients required for the entire growth period of potatoes is the same as 1.1. the

2.2 Calculation of soil nutrient supply

The calculation method is the same as 1.2. the

2.3 Determination of potato fertilization amount

The calculation method is the same as 1.3. Considering the obvious aftereffect of phosphorus fertilizer, the application of phosphorus fertilizer can be reduced by 60%. Calculated by the above method, when the potato yield per mu is 1250 kg, 6.3 kg of nitrogen and 0.3 kg of phosphorus are needed per mu of land; when the potato yield is 1750 kg per mu, 14.9 kg of nitrogen, 1.6 kg of phosphorus, 5.4 kg; when the potato yield per mu is the local average yield (1500 kg), fertilize according to the customary amount of local farmers, that is, the customary application of nitrogen per mu is 9.2 kg of nitrogen, 1.1 kg of phosphorus, and 0.7 kg of potassium. the

2.4 Specific distribution of nutrients during the potato growth period

Potatoes absorb 6% nitrogen, 8% available phosphorus, and 9% available potassium at the seedling stage; 38% nitrogen, 34% available phosphorus, and 36% available potassium during the growth period; 56% nitrogen, 58% available phosphorus, and available potassium at the mature stage 55%. The calculation method is the same as 1.4. the

2.5 Determination of the amount of potato commercial fertilizer

The tested fertilizers are: commercially available urea (containing 46.4% of N), superphosphate (containing 16% of P ₂ O ₅ ), and potassium sulfate (containing 52% of K _{2 O} ). The calculation method is the same as 1.5.

Through soil testing and formula fertilization technology, the amount of fertilizer required for the inner layer (mature stage), middle layer (growing stage) and outer layer (seedling stage) of the slow-release fertilizer can be calculated according to the above method, and the attapulgite content of each layer wrapped accounts for 20% or 30% of the total weight of each layer. The preferred scheme for realizing the present invention is that the content of attapulgite wrapped in each layer accounts for 30% of the total weight of each layer. The specific formula is shown in Table 1-10. The present invention is suitable to be used as base fertilizer, that is, evenly spread before or after plowing, plowing into the soil, and in actual application, it can also be combined with the actual conditions of different soils and different crops, and the fertilization in the formula can be appropriately adjusted according to the soil testing formula fertilization technology quantity. the

In 2010, four kinds of fertilizers, 20% PCF, 30% PCF, 20% PMF, and CF were used in the potato field experiment. A total of 12 treatments were set up, with 3 repetitions, arranged randomly, and the area of the plot was 8.5 square meters. In 2011, three kinds of fertilizers, 30% PCF, 30% PMF, and CF were used in the potato field experiment. There were 9 treatments in total, 3 repetitions, arranged randomly, and the area of the plot was 22 square meters. the

On the basis of the above and with reference to the amount of soil used in the attapulgite slow-release fertilizer in the prior art, the fertilizer ratio of each layer of fertilizer granules and the attapulgite consumption in the present embodiment are determined, referring to Table 11 and Table 12. 11 and Table 12 formula weigh each component to manufacture corn layered ring-wrapped slow-release fertilizer (PCF represents layered ring-wrapped slow-release fertilizer, 20% represents the weight of each layer of ring-wrapped attapulgite soil in this layer and the corresponding wrapped attapulgite 20% of the total weight of the soil layer, 30% means that the weight of attapulgite soil surrounding each layer accounts for 30% of the total weight of the layer and the corresponding wrapped attapulgite soil layer, 1, 2, and 3 represent 1250kg/mu and 1500kg respectively Three different target yields per mu and 1750kg/mu. 

Table 11. Potato layered ring-wrapped slow-release fertilizer formula (20% PCF) 

Table 12. Potato layered ring-wrapped slow-release fertilizer formula (30% PCF) 

Table 13 and Table 14 respectively provide the attapulgite slow-release fertilizers prepared according to the prior art, and Table 15 provides the formulas of direct fertilization commonly used by farmers in the test area for comparison. Wherein in Table 3 and Table 4, 20% and 30% of attapulgite weight account for 20% and 30% of the total weight of attapulgite and used fertilizer respectively. the

Table 13. Potato attapulgite mixed control formula (20% PMF)

Table 14. Potato attapulgite mixed control formula (30%PMF)

Table 15. Potato Fertilizer Control Formula (CF)

The test material of this embodiment adopts the attapulgite same as the aforementioned corn fertilizer; the test fertilizers are commercially available urea (containing N46.4%), _{superphosphate} (containing _P2O5 16%), potassium sulfate (containing K ₂ O52%); the preparation method of the slow-release fertilizer granules and comparative examples is the same as the preparation method of the aforementioned corn fertilizer.

In 2010, four kinds of fertilizers, 20% PCF, 30% PCF, 20% PMF, and CF were used in the potato field experiment. A total of 12 treatments were set up, with 3 repetitions, arranged randomly, and the area of the plot was 8.5 square meters. In 2011, three kinds of fertilizers, 30% PCF, 30% PMF, and CF were used in the potato field experiment. There were 9 treatments in total, 3 repetitions, arranged randomly, and the area of the plot was 22 square meters. the

In 2010, the potato experiment was planted in the open field, and in 2011, it was planted with film and film. The tested variety was Longshu No. 5, and 31,000 seedlings were preserved per hectare of land. In view of the severe spring drought in the local area, the experimental field is plowed in time after the soil surface is thawed in the middle and late March of each year, and the above-mentioned fertilizers are applied at one time in combination with the plowing. No topdressing is required during the growth period. Sow in late April and harvest in early October . the

3. Main measurement items and methods

When the potatoes are harvested, the production is calculated according to the single harvest of the plot, and they are classified according to the large potatoes (above 100g), medium potatoes (50-100g), and small potatoes (below 50g). Stems, leaves and tubers are separated, dried (105°C, 70°C after 1 hour, measured dry mass after 72 hours.

4. Statistical analysis of data

After testing the normal distribution of the experimental data, ANOVA in SAS statistical analysis software was used for analysis of variance. Use Excel for graphing. the

5. Experimental results

The experimental results are shown in Table 16-Table 20. the

Table 16. Yield indicators of potato field experiments in 2010

Table 17. Yield indicators of potato field experiment in 2010

Table 18. Fertilizer use efficiency of potato field experiments in 2010

Table 19. Yield indicators of potato field experiments in 2011

Table 20. Fertilizer use efficiency of potato field experiments in 2011

For the potato field experiment in 2010, Table 16 shows that the attapulgite-layered wrapping treatment has a significant increase in yield and water use efficiency, compared with the control, the yield increase is 13.3%-25.8%. The effect of 30% attapulgite encircling treatment is better than that of 20% encircling treatment. Table 17 shows that the fertilizer partial productivity of nitrogen fertilizer, phosphorus fertilizer and potassium fertilizer under the attapulgite layered wrapping treatment has been significantly improved. The effect of 30% attapulgite encircling treatment is better than that of 20% encircling treatment. the

For the potato field experiment in 2011, Table 19 shows that the treatment of 30% attapulgite layered encirclement has significantly improved the yield, commercial rate and water use efficiency, compared with the control, the yield increased by 10.6%-14.7%. Table 20 shows that the fertilizer partial productivity of nitrogen fertilizer, phosphorus fertilizer and potassium fertilizer treated with 30% attapulgite layered ring wrapping treatment has been significantly improved. the

In the above test, in order to detect the release effect of slow-release fertilizers in the soil, open up a plot with an area of 1 square meter separately, and apply CF2, 30% PCF2 and 30% PMF2 in Table 7, Table 9, and Table 10 respectively. Three kinds of fertilizers, no crops, from April 28, 2011 to September 28, 2011, the soil was collected every other month to track the changes of available phosphorus and inorganic nitrogen, and evaluate the release effect of slow-release fertilizers. The results are shown in Figure 4 and Figure 5. Figure 4 shows that: in the soil treated with attapulgite ring-wrapped fertilizer, the inorganic nitrogen reached the highest value at the fifth sampling point; in the soil of the control treatment, the inorganic nitrogen reached the highest value at the third sampling point; the mixed treatment was between between the two. It shows that the attapulgite enclosing chemical fertilizer has a certain slow-release effect. Figure 5 shows that: in the soil treated with attapulgite ring-wrapped fertilizer, the available phosphorus reached the highest value at the fifth sampling point; in the soil of the contrast treatment, the available phosphorus reached the highest value at the third sampling point; the mixed treatment was between between the two. It shows that the attapulgite enclosing chemical fertilizer has a certain slow-release effect. the

In order to test the effect of slow-release fertilizer absorption by plants, from June 30, 2011 to August 30, 2011, 27 potato plots were taken every half a month to take potato leaves, track the changes in inorganic nitrogen content, and evaluate the slow-release fertilizer Fat release effect. The results are shown in Figures 6-8. Figures 6 to 8 show that: under the three fertilization gradients, the inorganic nitrogen content of potato leaves is lower than that of the control and mixed treatments at the first two sampling points, while at the last two sampling points The content of inorganic nitrogen in potato leaves treated with soil ring wrapping was higher than that of control and mixed treatments, which indicated that the attapulgite soil ring wrapping fertilizer had a certain slow-release effect. the

Claims (1)

1. A slow-release fertilizer applicable to corn is characterized in that the used nitrogen fertilizer of fertilizer granules is urea, and the phosphorus fertilizer used is superphosphate, and the relative weight ratios of nitrogen and phosphorus fertilizer in each layer are respectively: outer layer=2.13～ 5.73: 0.25-0.57; middle layer = 48.31-130.37: 14.35-32.53; inner layer at the core = 43.78-118.13: 7.89-17.88; the weight of the attapulgite layer between each fertilizer layer and the corresponding wrapped fertilizer layer and attapulgite layer The ratio of the total layer weight is 0.2-0.3. 2. A kind of slow-release fertilizer applicable to potatoes is characterized in that the used nitrogen fertilizer of the fertilizer granule is urea, the phosphate fertilizer used is superphosphate, and the potash fertilizer used is potassium sulfate, and the weight of nitrogen, phosphorus, and potash fertilizer in each layer The ratios are: outer layer = 5.67～13.4: 0.36～1.92: 0～7.29; middle layer = 35.89～84.89: 14.35～32.53: 0～29.15; inner layer at the core = 52.89～125.1: 2.61～13.91: 0～44.53 The ratio of the weight of the attapulgite soil layer between the fertilizer layers to the total weight of the corresponding wrapped fertilizer layer and the attapulgite soil layer is 0.2-0.3. 3. the preparation method of the described slow-release fertilizer of claim 1 is characterized in that urea, superphosphate are pulverized into the powder that diameter is less than or equal to 1mm earlier, take by weighing the various fertilizer powders of core inner layer by predetermined weight and Sprinkle water as a binder for granulation. After most of the fertilizer is formed, put in a certain amount of attapulgite, and continue to sprinkle water so that attapulgite is evenly wrapped on the outside of the fertilizer granules to form the inner layer of slow-release fertilizer granules; then put in a certain amount of attapulgite. The weight of the fertilizer in the middle layer, sprinkle water to make it evenly wrapped outside the round grains of the slow-release fertilizer in the inner layer, then add a certain amount of attapulgite, sprinkle water to make it continue to wrap around the grains, and form layers of slow-release fertilizer grains layer by layer . 4. the preparation method of the described slow-release fertilizer of claim 2 is characterized in that earlier urea, superphosphate and potassium sulfate are pulverized into the powder that diameter is less than or equal to 1mm, weighs the various fertilizers of core inner layer by predetermined weight Powder and sprinkle water as a binder for granulation. After most of the fertilizer is formed, put in a certain amount of attapulgite and continue to sprinkle water so that attapulgite is evenly wrapped on the outside of the fertilizer granules to form the inner layer of slow-release fertilizer granules; then put in Determine the weight of the fertilizer in the middle layer, sprinkle water to make it evenly wrapped outside the round grains of the slow-release fertilizer in the inner layer, then add a certain amount of attapulgite, sprinkle water to make it continue to wrap the grains, so that the slow-release fertilizer grains are formed layer by layer layers.

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