CN102924176A - Sustained oxygen release fertilizer and preparation method thereof - Google Patents

Abstract

The invention discloses a sustained oxygen release fertilizer which adopts a mixture comprising calcium superoxide, sodium bentonite and polyvinyl formal. The mass ratio of sodium bentonite to calcium superoxide is 12 to 5, and the mass of the polyvinyl formal is 15 percent of the gross mass of the sustained oxygen release. The sustained oxygen release fertilizer discusses the oxygen release feature and the pH value variation in the condition of aqueous medium. Experimental results show that compared with applying calcium superoxide powder only, the sustained oxygen release fertilizer has the characteristics that the fertilizer effect period is long, the applying method is simple, the production technology is simple, the source of material selected is wide, the material is environmentally friendly, and the sustained oxygen release fertilizer can be widely applied.

Description

A kind of slow and controlled release oxygen fertilizer and preparation method thereof

Technical field:

The invention relates to the field of agricultural and forestry slow and controlled release oxygen fertilizer and its preparation, especially a kind of fertilizer with good slow control performance, long fertilizer effect period, high bioavailability and environment friendly, which can be used for long-term slow-release fertilizers such as flooded plants. Novel oxygen fertilizer for supplying oxygen in a controlled release and a preparation method thereof.

Background technique:

my country has an East Asian monsoon climate, with an unstable climate system, and large seasonal and regional changes in rainfall; the long-term population growth and the pressure of social and economic development have intensified the contradiction between man and nature, making my country's flooding disaster environment It is more sinister, especially in the eastern and central regions of my country. Wet damage is widely distributed in my country, and there are different degrees of wet damage in about 2/3 of the country's land area, and the loss is serious. According to statistics from 1950 to 1990, the average annual flood disaster area in my country reached 8.14 million hectares, the disaster area was 4.48 million hectares, the loss of food was about 2.8 billion kilograms, and the direct economic loss was 10-20 billion yuan; There are 5.4 million hectares of cultivated land prone to waterlogging, accounting for 25.15%; 14 southern provinces (cities, districts) have nearly 10 million hectares of waterlogged land, accounting for 86% of all kinds of low-yield fields in the region. The waterlogged land treated by preliminary treatment) accounted for only 31% of the total waterlogged land. Floods cause excess water in the soil, and there is a mutual restriction between the water in the soil and the content of oxygen. Excessive water replaces the oxygen in the soil, resulting in a lack of oxygen. This is the key to plant waterlogging. The various hypoxic and anaerobic stress states caused by the decrease of oxygen concentration in the rhizosphere of plants caused by soil flooding have affected the normal physiological metabolism and growth and development of plants. In order to adapt to or alleviate the damage caused by flooding, plants undergo a series of waterlogging responses, including temporary changes in metabolism and gene expression, as well as long-term developmental responses and morphological changes. The impact of flooding on plants is quite complex, including: inhibition of energy metabolism, photosynthesis, inhibition of respiration, inhibition of water and nutrient absorption, changes in hormone levels, changes in oxygen production and antioxidant systems, and accumulation of metabolites and toxic effects, the increase of osmotic adjustment substances, the production of anaerobic proteins, the transmission of signals, etc.

At present, there is an urgent need to determine reliable and intuitive physiological and biochemical indicators for waterlogging damage identification and the solution: through cloning of forest waterlogging resistance genes, construction of water conservancy, and timely drainage of waterlogging, the effect is still not obvious, and there is still no great effect on solving plant hypoxia . This research topic will introduce a brand new concept from a brand new perspective, starting from the fertilizer necessary for plant growth, a new type of slow and controlled release oxygen fertilizer. Oxygen fertilizer is the abbreviation of oxygen fertilizer. It is relatively stable in dry conditions. When it encounters water, it can slowly release oxygen. The oxygen supply is usually peroxide. The existing oxygen fertilizer is mainly the direct application of calcium peroxide, which is mainly used for small-scale agricultural planting (such as seed growth and germination), aquaculture, food preservation, etc. , to generate calcium hydroxide to make the pH value of the aqueous solution as high as 12-13. Direct application to flooded plants will seriously affect the soil pH, resulting in soil colloidal compaction and salinization, corroding the roots of plants, and thus affecting the normal growth of plants. At the same time, the direct application of calcium peroxide cannot play a role in slowly controlling the release of oxygen. The fertilizer retention performance is not ideal.

In addition, many studies have shown that the current effective utilization rate of inorganic fertilizers in my country is only 30% to 35%, causing serious economic losses and environmental pollution. Therefore, improving the utilization rate of chemical fertilizers, reducing its pollution to the environment, and developing sustainable and efficient agriculture and forestry have become common concerns of all countries. Since the 1970s, the development and application of slow and controlled release fertilizers has provided a new idea for solving the above problems. Slow and controlled release fertilizers can effectively control the release of nutrients, prolong the period of fertilizer effectiveness, and meet the needs of crops for fertilizer nutrients throughout the growth period. , It can maximize the utilization rate of fertilizers, reduce resource waste and environmental pollution, and play an important role in promoting agricultural and forestry production, increasing farmers' income, and sustainable development of agriculture and forestry. It is an important development direction of the fertilizer industry in the 21st century. At present, the total annual consumption of inorganic fertilizers in the world is 110 million tons, while the consumption of coated slow-release fertilizers is less than 500,000 tons. The main reason is that the cost of slow-release fertilizers is too high, which is 2-6 times that of general fertilizers Times, if we can focus on improving production technology and application methods, find low-cost slow-release materials, and further reduce fertilizer production costs, then there must be a huge market space for slow-release fertilizers. In this invention, the selected clay minerals just meet the requirements of the current fertilizer market. It has a wide range of sources and is cheap. Higher professional researchers have done application tests of bentonite fertilizer on rice, cotton and rapeseed. A good amendment can change the ratio of solid, liquid and gas in the soil, and has the advantages of loose soil structure, water retention, and fertilizer retention.

Therefore, the research on the mechanism and technology of slow and controlled release fertilizers should be strengthened, and new slow and controlled release fertilizers that conform to the international development trend of "slow effect, fluidization, compounding, specialization and high efficiency" should be developed to solve the impact of floods on agriculture and forestry. The loss of production is of great significance.

Invention content:

The purpose of the present invention is to provide a kind of slow-controlled release oxygen fertilizer and its preparation method which has wide sources of materials, environment-friendly, long fertilizer effect period, simple application method and simple production process.

The technical scheme that realizes the above-mentioned purpose of the invention is as follows:

A kind of slow and controlled release oxygen fertilizer, it is the mixture that comprises calcium peroxide, sodium-based bentonite and polyvinyl formal; The mass ratio of described sodium-based bentonite and calcium peroxide is 12:5, polyvinyl formal The content accounts for 15% of the total mass of slow and controlled release oxygen fertilizer.

The preparation method of described slow and controlled release oxygen fertilizer, comprises the following steps:

(1) Take the corresponding quality of calcium peroxide powder and sodium bentonite and fully pulverize and mix them;

(2) Add a corresponding proportion of polyvinyl formal solution to the mixture and mix well to make a soft material;

(3) After standing at room temperature for 2-3 hours, extrude into small particles;

(4) The small particles are baked and pressed into shape;

(5) Natural moisture absorption, that is, slow and controlled release oxygen fertilizer samples.

The extruding into small particles in step (3) is extruding through 8-10 mesh sieves.

In step (4), the small particles are baked at 50-60° C. for 30 minutes.

The condition for natural moisture absorption in step (5) is to absorb moisture naturally for 12 hours at a humidity of 80%.

The pretreatment method of the sodium-based bentonite is: after the sodium-based bentonite is purified by a wet method, the mass content of the montmorillonite is between 30% and 80%, and it is passed through a 0.025mm sieve, and then placed in In an oven, bake at 105°C for 2 hours, and take it out for later use.

The preparation method of the polyvinyl formal solution is as follows: weigh 5g of polyvinyl alcohol and place it in a glass beaker, add 100mL of deionized water and 5mL of formaldehyde, then stir on a magnetic stirrer for 10min to make it uniform, and then put In a constant temperature water bath, gradually increase the temperature to dissolve it, and keep stirring; keep it at a constant temperature of 80°C for 30 minutes.

The present invention has the following advantages:

1. Provide oxygen for flooded plants: relieve all kinds of hypoxic stress and anaerobic stress caused by the reduction of oxygen concentration in the rhizosphere of flooded plants, maintain the normal physiological metabolism and growth and development of plants, thereby reducing the impact of floods on my country's agriculture and forestry Economic losses.

2. Long fertilizer effect period: The new type of slow and controlled release oxygen fertilizer is relatively new and innovative in material processing, and it is also a trend in the production of modern slow and controlled release fertilizers, which has a large market space; The oxygen release time of the new slow and controlled release oxygen fertilizer can last for nearly a month. Compared with the current direct use of calcium peroxide, it will not cause harm to plants, the oxygen release time is longer, and the oxygen release amount is more stable.

3. Wide range of sources of materials, low price, and environmental friendliness: my country is rich in clay mineral resources, and clay minerals are widely used in agriculture. Bentonite is a very good modifier. It can change the ratio of solid, liquid, and gas in the soil, and has the advantages of loose soil structure, water retention, and fertilizer retention, without causing soil compaction.

4. The production process is simple and the operation is simple: the preparation equipment of this new type of slow and controlled release oxygen fertilizer is simple, the operation is simple, the production environment is not strict, and hot air is introduced during the process to keep the entire production environment dry (calcium peroxide is due to encounter Water needs a dry environment to release oxygen). The invention not only simplifies the process of the production process, but also improves the production efficiency, reduces the production cost, saves the production space and energy, and has no pollution discharge.

Description of drawings

Fig. 1 is to draw the relationship curve of oxygen accumulative stripping amount and water immersion time;

It can be seen from Figure 1 that during the whole test period, the hydroponics control has been at a low level of oxygen immersion, and the trend of oxygen immersion in calcium peroxide hydroponics is to rise first and then decrease, and the oxygen immersion reaches its peak on the 12th day. Then it turned to a rapid decline, and the oxygen release rate of the slow-release oxygen fertilizer in hydroponics continued to be maintained at about 32 days, and its curve was gentler and longer than that of calcium peroxide. To slowly release oxygen and provide oxygen to flooded plants.

Fig. 2 is to draw the relation curve of pH value and water immersion time.

It can be seen from Figure 2 that throughout the test, the pH value of the hydroponic control was kept at 7, and the pH value of calcium peroxide was kept at a very high strong alkaline level. However, the pH value of the slow-release oxygen fertilizer has been at a low level of pH < 8 and is very stable, indicating that the application of a small amount of slow-release oxygen fertilizer will not change the acidity and alkalinity of the soil. It will cause soil compaction and affect the normal growth of plants.

Detailed ways

The following in conjunction with specific embodiments is intended to further illustrate the present invention, rather than limit the present invention.

Optimization of the preparation process of slow and controlled release oxygen fertilizer of the present invention

1. Performance parameters of bentonite

Using calcium-based raw ore soil, calcium-based bentonite and sodium-based bentonite as fertilizers as fillers, the basic performance parameters of bentonite, such as blue absorption, expansion capacity, colloidal value and cation exchange capacity, were tested according to the national standard testing method, and the test results see table 1

Table 1 The basic performance parameters of bentonite used in experiments

Blue absorption amount: montmorillonite is dispersed in aqueous solution and has the ability to absorb methylene blue. The amount of its adsorption is called blue absorption amount, expressed in milligram equivalents or grams of methylene blue adsorbed by 100 grams of sample. The higher the content of montmorillonite, the more blue-absorbing amount, therefore, the blue-absorbing amount can be used as the main technical index to roughly estimate the relative content of montmorillonite.

Expansion capacity: The expansion performance of bentonite is expressed by expansion capacity, and the volume of bentonite after swelling in dilute hydrochloric acid solution is called expansion capacity, expressed in ml/gram sample. It can be seen from Table 1 that the expansion capacity of sodium-based bentonite is higher than that of calcium-based raw ore soil and calcium-based bentonite. For the same type of bentonite, the more montmorillonite it contains, the higher the swelling capacity. Expansion capacity is one of the technical indicators for identifying the type of bentonite ore and evaluating the quality of bentonite.

Colloidal value: after bentonite and water are mixed in proportion, the volume of the gel formed by adding an appropriate amount of magnesium oxide to make it condense is called the colloidal value, expressed in milliliters of the gel volume formed by a 15-gram sample. The colloidal value shows the degree of particle dispersion and hydration of the sample, which is a comprehensive performance of dispersibility, hydrophilicity and swelling. Its size is closely related to the type of bentonite ore and the content of montmorillonite. It can be seen from Table 1 that the colloid price of sodium-based bentonite is higher than that of calcium-based raw ore and calcium-based bentonite. For the same type of bentonite, the more montmorillonite it contains, the higher the price of colloid. Therefore, colloid price is one of the technical indicators for identifying the type of bentonite ore and evaluating the quality of bentonite.

Cation exchange capacity refers to the total amount of K ⁺ , Na ⁺ , Ca ²⁺ , Mg ²⁺ and other cations adsorbed under the condition of pH 7, referred to as CEC. The cation exchange capacity and exchangeable cations of bentonite ore are the main basis for judging the quality of bentonite ore and classifying the type of bentonite ore. The larger the CEC value, the greater the negative charge, and the stronger its hydration, expansion and dispersion capabilities; on the contrary, its The weaker the hydration, expansion and dispersion ability.

It can be concluded from Table 1 that the four basic performance parameters of sodium-based bentonite are significantly better than those of calcium-based raw ore soil and calcium-based bentonite, indicating that the relative content of montmorillonite in sodium-based bentonite is higher, and the ore type and quality are better. It can be seen that it is more suitable to choose sodium bentonite as fertilizer filler.

result

Influence of Bentonite Types on Slow-release Effect of Oxygen Fertilizer

Calcium-based raw ore soil, calcium-based bentonite and sodium-based bentonite were used as fillers to prepare fertilizers, and the slow and controlled release oxygen fertilizer was prepared under the conditions of a soil-to-fertilizer ratio of 12:5 and a polyvinyl formal dosage of 15%. Dissolution experiments were carried out to investigate the effects of different types of bentonite on the slow-controlled release performance of fertilizers. The test results are shown in Table 2

Table 2 Oxygen leaching amount of different types of bentonite slow-release oxygen fertilizers in hydrostatic culture at 25°C

It can be seen from Table 2 that in the static water dissolution environment, the slow-release effect is better for sodium-based bentonite and calcium-based bentonite, and the effect of calcium-based raw ore soil is poor. This is mainly because calcium-based raw ore soil contains more sand particles. And other impurities, leading to the decline in the quality of bentonite, which is not conducive to the oxygen-containing unit of calcium peroxide entering the interlayer structure of bentonite to form a slow-release component of fertilizer. The grade of sodium-based bentonite is higher than that of calcium-based bentonite. It has the advantages of good structure dispersion and strong ion adsorption performance, so it has better slow-release effect. Therefore, sodium bentonite was selected for subsequent experiments.

Effect of Soil Fertilizer Ratio on Slow Release Effect of Fertilizer

Using sodium-based bentonite as a filler, the mass ratio of bentonite: calcium peroxide: polyvinyl formal is 12:5:3, 10:7:3, 8:9:3 to prepare slow and controlled release fertilizers, in static water Dissolution experiments were carried out in the environment to investigate the effect of soil-fertilizer ratio on the slow-release performance of fertilizers. The oxygen content in the still water environment is shown in Table 3

Table 3 Oxygen leaching amount in hydrostatic culture at 25°C with different soil-fertilizer ratios and slow-release fertilizers

It can be seen from Table 3 that the oxygen content of the slow and controlled release oxygen fertilizer in the first seven days gradually increased with the decrease of the soil-to-fertilizer ratio, and decreased rapidly when the oxygen concentration in the water reached saturation, that is, the mixed calcium peroxide increased. Under the same culture conditions, the dissolved oxygen will reach saturation in a short period of time, and then decrease rapidly. Explain that when the calcium peroxide content in the slow-release fertilizer increases to a certain amount, the excessive calcium peroxide cannot be effectively adsorbed on the bentonite carrier, and is easily dissolved by water, and with the increase of the calcium peroxide amount, the pH value of the solution also decreases. will rise and pose a threat to plant growth. Therefore, when preparing slow-release fertilizers, an appropriate soil-to-fertilizer ratio should be selected so that it can not only meet the oxygen demand of crop growth, but also give full play to the slow-release effect of bentonite on oxygen fertilizer. Under the conditions of this experiment, the appropriate soil-to-fertilizer ratio was selected as 12:5.

Influence of Polyvinyl Formal Content on Slow Release Effect of Oxygen Fertilizer

Using sodium-based bentonite as a filler, the ratio of soil to fertilizer is 12:5, and the content of polyvinyl formal is 5%, 10%, 15%, 20%, and 25%, respectively, to prepare slow-release fertilizers, and dissolve them in a still water environment The experiment was conducted to investigate the effect of polyvinyl formal content on the slow-release performance of fertilizers. The oxygen content in still water environment is shown in Table 4,

Table 4 Oxygen leaching amount of slow-release oxygen fertilizer with different content of polyvinyl formal in hydrostatic culture at 25°C

It can be seen from Table 4: in 1 to 20 days, when the content of polyvinyl formal is 5%, 10%, 15%, the oxygen leaching amount of slow and controlled release oxygen fertilizer in hydrostatic culture increases with the increase of polyvinyl formal. The formaldehyde content increased and decreased, and in the last 12 days, the oxygen leaching amount of the slow-release oxygen fertilizer in hydrostatic culture increased with the increase of the polyvinyl formal content, that is, the higher the polyvinyl formal content , the better the slow-release performance of the fertilizer, the higher the effective utilization rate of oxygen fertilizer. However, when the amount of polyvinyl formal increases to 20% and 25%, the difference is not significant. Considering technical and economical aspects, the appropriate content of polyvinyl formal is 15%.

in conclusion

A new type of slow and controlled release oxygen fertilizer is prepared by using natural and cheap sodium bentonite as calcium peroxide filler and adding polyvinyl formal binder.

(1) The type of bentonite has a certain influence on the slow-release performance of slow-release oxygen fertilizer. The grade of sodium-based bentonite is higher than that of calcium-based bentonite and calcium-based raw ore soil. It has the advantages of good structural dispersion and strong ion adsorption performance, so it has Better sustained release effect.

(2) When the soil-to-fertilizer ratio is 12:5, 10:7, and 8:9, as the soil-to-fertilizer ratio increases, the oxygen content of the slow-release oxygen fertilizer tends to increase, that is, the greater the proportion of bentonite , the better the slow release performance of slow and controlled release fertilizer, the higher the effective utilization rate of oxygen fertilizer.

(3) When the content of polyvinyl formal is 5%, 10%, 15%, 20%, and 25% respectively, considering the technical and economical aspects, the appropriate content of polyvinyl formal is 15%.

(4) Under the conditions of using sodium bentonite as filler, soil-to-fertilizer ratio of 12:5, and polyvinyl formal content of 15%, the slow-release effect of the new slow-release oxygen fertilizer prepared is the best.

Instruments used:

H18424 electronic balance

FW135 Chinese herbal medicine grinder

TDP-1.5 electric tablet press machine

HPX-150BS centrifuge

101-3-BS type electric heating constant temperature blast drying oven

SX725 pH/mV Dissolved Oxygen Meter

step:

(1) Pretreatment of sodium bentonite: after wet purification of sodium bentonite, the mass content of montmorillonite is between 30% and 80%, and passed through a 0.025mm sieve to produce the required sodium bentonite base bentonite, then put the sodium base bentonite in an oven, bake at 105°C for 2 hours, and take it out for later use.

(2) Preparation of polyvinyl formal solution: Weigh 5g of polyvinyl alcohol into a glass beaker, add 100mL of deionized water and 5mL of formaldehyde, then stir on a magnetic stirrer for 10min to make it uniform, and then put it into a constant temperature water bath In the pot, gradually raise the temperature to dissolve it, and keep stirring; keep it at a constant temperature of 80°C for 30 minutes, and set aside.

(3) According to the mass ratio of sodium-based bentonite and calcium peroxide of 12:5, take the corresponding quality of calcium peroxide powder and sodium-based bentonite to fully pulverize and mix; 15% of the mass, add a corresponding proportion of polyvinyl formal solution to the mixture and mix well to make a soft material;

(4) After standing at room temperature for 2-3 hours, squeeze it into small particles through a 8-10 mesh sieve;

(5) Bake the small particles at 50-60°C for 30 minutes and then press into tablets;

(6) Naturally absorb moisture for 12 hours under the condition of 80% humidity to obtain slow and controlled release oxygen fertilizer samples.

Performance Evaluation of New Type Slow and Controlled Release Oxygen Fertilizer

1. Preparation of a new type of slow and controlled release oxygen fertilizer extract by using the dissolution method in water

Weigh about 2g of oxygen fertilizer particles, put them in a self-made 300-mesh filter bag, put the filter bag in a 250ml ground-mouth conical flask, add 250ml of distilled water, and then put the conical flask into a 25°C constant temperature incubator for cultivation , respectively extract a small part of the extract solution on the 1d, 3d, 5d, 7d, 10d, 15d, 20d, 25d, 30d, and 32d of the culture, add an equal volume of distilled water to the Erlenmeyer flask after extracting the extract solution, Continue to cultivate and extract.

2. Determination of oxygen content in the extract

After the extract was filtered through a medium-speed qualitative filter paper, the oxygen content in the filtrate was measured, and the relationship curve between the cumulative oxygen dissolved amount and the water immersion time was drawn. Each experiment was repeated 3 times for parallel determination. Strictly follow the operation specification of SX725 pH/mV dissolved oxygen measuring instrument. It should be noted that the oxygen content in water is negatively correlated with temperature, and the temperature has a great influence on the oxygen content of water, so a unified reference standard should be set when measuring Temperature, the experiment is the data measured at 25°C.

Claims (7)

1. a slow controlled release oxygen is fertile, it is characterized in that it is the mixture that comprises calcium peroxide, sodium bentonite and polyvinyl formal; The mass ratio of described sodium bentonite and calcium peroxide is 12:5, and polyvinyl formal content accounts for 15% of the fertile total mass of slow controlled release oxygen.

2. the preparation method of slow controlled release oxygen fertilizer claimed in claim 1 is characterized in that, may further comprise the steps:

(1) calcium peroxide powder and the sodium bentonite of getting respective quality are fully pulverized mixing;

(2) add the polyvinyl formal solution mixing of corresponding proportion in the mixture, make softwood;

(3) room temperature was placed after 2-3 hour, was squeezed into small-particle;

(4) with compression moulding after the small-particle baking;

(5) natural moisture absorption namely gets the fertile sample of slow controlled release oxygen.

3. the preparation method of slow controlled release oxygen fertilizer according to claim 2 is characterized in that, being squeezed into small-particle in the step (3) is to push by 8～10 mesh sieves.

4. the preparation method of slow controlled release oxygen fertilizer according to claim 2 is characterized in that, is that small-particle is toasted 30min in 50～60 ℃ in the step (4).

5. the preparation method of slow controlled release oxygen fertilizer according to claim 2 is characterized in that, the condition of natural moisture absorption is natural moisture absorption 12h under humidity 80% condition in the step (5).

6. the preparation method of slow controlled release oxygen fertilizer according to claim 2, it is characterized in that, the pre-treating process of described sodium bentonite is: after sodium bentonite is adopted wet purification, make the mass content of montmorillonite wherein between 30%-80%, and cross 0.025mm and sieve, then be placed in the baking oven, under 105 ℃ of conditions, dry by the fire 2h, take out for subsequent use.

7. the preparation method of slow controlled release oxygen fertilizer according to claim 2, it is characterized in that, described polyvinyl formal solution preparation method is: take by weighing the 5g polyvinyl alcohol and place glass beaker, add 100mL deionized water and 5mL formaldehyde, then on magnetic stirring apparatus, stir 10min, make it evenly to put into again thermostat water bath, heating up gradually makes it dissolving, and constantly stirs; Under 80 ℃ of constant temperatures, keep 30min to get final product.

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