CN114644457A

CN114644457A - Slow release fertilizer for soilless culture

Info

Publication number: CN114644457A
Application number: CN202011509411.5A
Authority: CN
Inventors: 郑卓群; 许佳宁; 胡斐杨; 朱东凯
Original assignee: Ningbo Shutong Technology Co ltd
Current assignee: Ningbo Shutong Technology Co ltd
Priority date: 2020-12-18
Filing date: 2020-12-18
Publication date: 2022-06-21

Abstract

The invention relates to a slow release fertilizer for soilless culture, which is phosphate glass. Unlike polyphosphate crystals, phosphate glass has a slow dissolution rate in water, which can be further controlled by formulation adjustments. The slow release fertilizer is applied to fix all nutrient components or part of the nutrient components required by crops, and then the nutrient components are released into water at a certain speed under the action of water, so that the problem that the content and concentration of the fertilizer in the water are difficult to control in the soilless culture process can be solved.

Description

Slow release fertilizer for soilless culture

The technical field is as follows:

the invention relates to a slow release fertilizer containing phosphorus and oxygen for soilless culture, belonging to the field of fertilizers.

Background art:

the development of chemical industry provides pesticides and chemical fertilizers for agricultural production. The yield per unit of crops is greatly improved, and the substance guarantee is provided for the survival of numerous people. However, with the widespread use of pesticides and fertilizers, the problem of environmental pollution also comes with it. The pollution of the chemical fertilizer is mainly eutrophication of water bodies, namely the chemical fertilizer is dissolved in rainwater, irrigation water and the like and is brought into underground water, rivers, lakes and other water bodies, so that elements such as nitrogen, phosphorus, potassium and the like in the water bodies exceed standards, aquatic organisms such as algae, water plants and the like are excessively propagated, a large amount of aquatic organisms are dead, and the water quality is further deteriorated.

Most of the carbon and hydrogen elements required for the growth of crops can be obtained from air and water through photosynthesis, and nitrogen, phosphorus and potassium need to be supplemented to different degrees to grow well. Besides nitrogen, phosphorus and potassium elements, crops also need various trace elements such as boron, fluorine, sodium, magnesium, sulfur, chlorine, potassium, calcium, manganese, iron, cobalt, nickel, copper, zinc, germanium, selenium, molybdenum, tin, iodine, rare earth and the like. Although the amount of trace elements required is small, if a plant lacks certain essential trace elements, the plant cannot be compensated by the increase of other nutrient components.

The current chemical fertilizers are generally easy soluble fertilizers, namely, are easy to dissolve in water. Soluble fertilizers have quick response, but have more disadvantages: because of high concentration, the seedling burning phenomenon is easy to generate; easily dissolved in water and easily carried away by water flow, including underground (beyond the root depth of crops and unable to be reused) and flowing into rivers and lakes with water. The method is not only unfavorable for environmental protection, but also reduces the utilization rate of the fertilizer, and causes the waste of the fertilizer. At present, the utilization rate of the fertilizer is 30-60 percent of nitrogen fertilizer, 10-25 percent of phosphate fertilizer and 40-70 percent of potassium fertilizer, and only about half of the fertilizer can be utilized.

With the rise of soilless culture, the nutrient solution can be recycled, and the utilization rate of the fertilizer is greatly improved. However, the content and the concentration of each nutrient substance need to be controlled more accurately in the soilless culture, and a soilless culture fertilizer applicator is generally needed so as to apply fertilizer regularly and quantitatively, thus increasing the workload and the difficulty of fertilizer application.

Phosphate glass is an important inorganic slow-release material, and unlike polyphosphate crystals, the phosphate glass has a slow dissolution rate in water. Through formula adjustment, the dissolution rate of phosphate in water can be further controlled. As a slow release agent, phosphate glass is used in the fields of water body scale inhibition and the like, but the application of the phosphate glass tends to be reduced due to the pollution of the phosphate to water bodies (mainly water body eutrophication). However, when the phosphate is applied to the agricultural field, the phosphate is not polluted but is a fertilizer; various macro elements and trace elements are combined to use through regulating the formula and designing a plurality of slow release agents, and the soilless culture can be conveniently applied.

The Chinese patent with publication number 1344695A discloses a phosphate glass for mineralizing and sterilizing drinking water, wherein phosphate only has a slow release effect and is a pollutant in nature, and the phosphate is different from the phosphate in the patent in that the phosphate is a necessary nutrient element for plants, and the product formula and the application field are different.

The invention content is as follows:

the slow release fertilizer is used for fixing all nutrient components or part of nutrient components required by crops, and then the nutrient components are released into water at a certain speed under the action of water, so that the problem that the content and concentration of the fertilizer in the water are difficult to control in the soilless culture process can be solved.

Phosphates are soluble with many oxides and form glassy states, for example, phosphorus pentoxide or polyphosphates with iron oxide, boron oxide, silicon oxide, calcium oxide, zinc oxide, manganese oxide, tin oxide, and the like can be formed into glassy states within certain limits. Therefore, the glass consisting of phosphate containing various nutrient components required by crops is very suitable to be used as a slow release agent for soilless culture.

Since phosphate glass has a certain composition range beyond which glass is not obtained, it is difficult to achieve a sustained release formulation, including all nutrients required by crops, that dissolves at a proper rate. The problem can be solved by designing several slow release agents with different formulas to be used together and collaboratively. Through a large amount of formula optimization, researchers of the invention find that the slow release fertilizer is phosphate glass, the mass percentage content of phosphorus oxide in the slow release fertilizer is 30-90%, and the mass percentage content of phosphorus oxide is preferably 45-80%. Besides phosphorus and oxygen elements, the slow release fertilizer also contains at least one of a plurality of elements such as boron, nitrogen, fluorine, sodium, magnesium, aluminum, silicon, sulfur, chlorine, potassium, calcium, manganese, iron, cobalt, nickel, copper, zinc, germanium, selenium, molybdenum, tin, iodine, lanthanum, cerium, praseodymium, neodymium and the like. Potassium, for example, is one of the important elements in fertilizers. Potassium is an activator of various enzymes in plants. Oxidoreductases, synthetases, transferases, phosphokinases and the like all require potassium activation and are involved in important physiological metabolism in plants, including sugar metabolism, protein metabolism, nucleic acid metabolism and the like. Potassium can also increase the activity of endogenous protection enzyme systems such as peroxidase and the like, and improve the capacity of plants to resist external environmental stimulation. Potassium can also enhance and regulate photosynthesis. The slow release fertilizer disclosed by the invention also contains a potassium element in addition to phosphorus and oxygen elements, and the mass percentage (calculated by potassium oxide) of the potassium element is more than 10%, and preferably 20% -55%.

The slow release fertilizer is prepared by mixing and melting compounds of corresponding elements. The melting temperature range for preparing the slow release fertilizer is 300-1400 ℃, and preferably 600-1200 ℃.

In the process of melting phosphate, the corrosivity is very strong, and in the experimental process, researchers of the invention find that a corundum crucible and a quartz crucible have good corrosion resistance; the graphite crucible and the boron nitride crucible are not soaked with phosphate melt and are not corroded below 500 ℃, phosphate glass needs to be melted under the protection of inert gas or vacuum above 500 ℃, otherwise the graphite crucible and the boron nitride crucible are easy to corrode at high temperature.

The soilless culture slow release fertilizer can bring the following beneficial effects:

1. the workload in the soilless culture process is reduced;

2. the application difficulty of the nutrient solution is greatly reduced;

the slow release effect is realized, so the service cycle is long, and the automatic management is convenient to realize. And (5) performing dynamic management.

Drawings

FIG. 1 shows the slow release fertilizer prepared in example 2, which is mainly a slow release fertilizer containing phosphorus, potassium, calcium and magnesium;

FIG. 2 shows the slow release fertilizer prepared in example 4, which is mainly a slow release fertilizer containing P, K, Ca, Mg, B and Sn.

The specific implementation mode is as follows:

example 1: crushing 60g of monopotassium phosphate, 40g of ammonium dihydrogen phosphate, 1g of boric acid, 6g of calcium hydroxide, 4g of magnesium hydroxide, 2g of manganese sulfate and 1g of zinc oxide, uniformly mixing, heating to 300 ℃ in a graphite crucible, preserving heat for 2 hours, and then slowly cooling to obtain a blocky solid.

Example 2: crushing 100g of monopotassium phosphate, 5g of potassium carbonate, 4g of calcium hydroxide, 4g of magnesium hydroxide and 2g of silicon dioxide, uniformly mixing, heating to 1400 ℃ in a graphite crucible under the protection of nitrogen, preserving heat for 1 hour, and then cooling at 2 ℃ per minute to obtain a colorless transparent solid. See fig. 1.

Example 3: 50g of sodium hexametaphosphate, 50g of monopotassium phosphate, 2g of manganese sulfate, 2g of calcium oxide, 2g of magnesium oxide, 1g of boric acid, 1g of iron oxide, 0.2g of cobalt hydroxide, 0.2g of copper oxide, 0.4g of zinc oxide, 0.2g of germanium oxide, 0.1g of selenium dioxide, 0.1g of tin dioxide, 0.05g of lanthanum nitrate, 0.05g of cerium nitrate, 0.05g of praseodymium nitrate and 0.05g of neodymium nitrate are crushed together, uniformly mixed, heated to 1000 ℃ in a graphite crucible under the protection of nitrogen, kept warm for 1 hour, and then cooled at 1 ℃ per minute to obtain a massive solid.

Example 4: 100g of potassium metaphosphate, 5g of magnesium sulfate, 4g of calcium oxide, 2g of zinc oxide, 1g of boric acid and 0.5g of tin oxide are crushed together, mixed uniformly, heated to 1200 ℃ in a quartz crucible and kept for 1 hour, then put in a boron nitride crucible at 1000 ℃, kept for 1 hour at 400 ℃, and then cooled at 0.5 ℃ per minute to obtain a solid with glass luster. See fig. 2.

Example 5: 86g of phosphorus pentoxide, 3g of magnesium oxide, 4g of calcium oxide, 2g of zinc oxide, 1g of boron oxide, 30g of potassium carbonate and 0.8g of sodium carbonate are crushed together, mixed uniformly, quickly heated to 1300 ℃ in a corundum crucible, kept at the temperature for 1 hour, put in a graphite crucible at 1000 ℃, kept at the temperature of 500 ℃ for 2 hours, and then cooled at 1 ℃ per minute to obtain the solid with glass luster.

Example 6: 12g of phosphorus pentoxide, 100g of dipotassium hydrogen phosphate, 3g of calcium oxide, 2g of magnesium oxide, 1g of boron oxide and 1g of zinc oxide are crushed together, uniformly mixed, quickly heated to 1100 ℃ in a corundum crucible, kept for 1 hour, put in a graphite crucible at 900 ℃, kept for 2 hours at 400 ℃, and then cooled at 0.8 ℃ per minute to obtain the glass-luster solid.

Table 1 description of slow release fertilizers made in the examples

Claims

1. The slow release fertilizer for soilless culture is characterized in that: the slow release fertilizer is phosphate glass, and the mass percentage content of phosphorus oxide in the slow release fertilizer is 30-90%.

2. The slow release fertilizer for soilless culture according to claim 1, wherein: the mass percentage content of the phosphorus oxide in the slow release fertilizer is 45-80%.

3. The slow release fertilizer for soilless culture according to claim 2, wherein: the slow release fertilizer contains phosphorus and oxygen elements, and also contains at least one of boron, nitrogen, fluorine, sodium, magnesium, aluminum, silicon, sulfur, chlorine, potassium, calcium, manganese, iron, cobalt, nickel, copper, zinc, germanium, selenium, molybdenum, tin, iodine, lanthanum, cerium, praseodymium and neodymium elements.

4. The slow release fertilizer for soilless culture according to claim 3, wherein: besides phosphorus and oxygen elements, the slow release fertilizer also contains potassium element.

5. The slow release fertilizer for soilless culture according to claim 4, wherein: the mass percentage content (calculated by potassium oxide) of potassium element in the slow release fertilizer is more than 10%.

6. The slow release fertilizer for soilless culture according to claim 5, wherein: the mass percentage content (calculated by potassium oxide) of potassium element in the slow release fertilizer is preferably 20-55%.

7. The slow release fertilizer for soilless culture according to claim 3, wherein: the slow release fertilizer is prepared by mixing and melting compounds of corresponding elements.

8. The slow release fertilizer for soilless culture according to claim 7, wherein: the melting temperature range for preparing the slow release fertilizer is 300-1400 ℃.

9. The slow release fertilizer for soilless culture according to claim 8, wherein: the melting temperature range for preparing the slow release fertilizer is preferably 600-1200 ℃.

10. The slow release fertilizer for soilless culture according to claim 7, wherein: graphite, corundum, quartz or boron nitride materials are preferably selected as the crucible for preparing the slow release fertilizer.

11. The slow release fertilizer for soilless culture according to claim 7, wherein: the slow release fertilizer is fired in air atmosphere, nitrogen atmosphere, argon atmosphere or vacuum.

12. The slow release fertilizer for soilless culture according to claim 1, wherein: the slow release fertilizer is used for agriculture, forestry, animal husbandry and is particularly suitable for soilless culture (water culture).