Shrimp ponds have ammonia nitrogen, nitrite, which is normal. If not, it means that the aquaculture water body may be thinner.
Generally speaking, when there is ammonia nitrogen and nitrite in the aquaculture water body of the shrimp pond, whether it is necessary to use inorganic fertilizer depends on the water body. In addition, we say "fat water", what is its essence? In fact, the core of fertilizer water is to establish a "stable algal phase". Ammonia nitrogen and nitrite will also play an important role in fertilizer water and stable water quality in the breeding process.
As can be seen from the definition of "fertilizer water", "fertilizer water" refers to making the biomass of beneficial algae reach a certain amount and maintaining a certain degree of activity and stability. From this description, it is clear that the key point of fertilizer water is to "establish a balanced algal phase of beneficial algae in the cultured water body".
<h1 class="pgc-h-arrow-right" >, what is fertilizer water</h1>
Since "fertilizer water is the algal phase that establishes equilibrium". The standard of fertilizer water can be set according to different algae, usually measured by transparency. Diatom beneficial algae (chlorpyrocytoidium) is usually 50-100 cm and green algae beneficial algae (chlorella) is 30-50 cm. Diasicolauconium 40-50 cm.
We use the following table to give you a rough reference to the "standard".
Extremely lean water: transparency (cm) >100; phytoplankton (mg/L) <5; clear and colorless water.
Lean water: transparency (cm) 100~50; phytoplankton (mg/L) 5~10; water color is colorless.
Fertilizer water: transparency (cm) 50~20; phytoplankton (mg/L) 10~100; water color algae color.
Polar fertilizer water: transparency (cm) 20~10; phytoplankton (mg/L) 100~200; water color thick algae color.
Old water: transparency (cm) <10; phytoplankton (mg/L) >200; water color is extremely rich algae.
<h1 class = "pgc-h-arrow-right" > the nutritional needs of algae</h1>
The nutrition of algae is mainly inorganic salts, including nitrogen, phosphorus, potassium, etc., which also have some trace elements, growth factors and carbon dioxide in water. However, due to the low carbon dioxide content in water, carbon dioxide can generally be obtained from the bicarbonate in the water to supply algae for photosynthesis.
By the speed of release, the nutrients needed by algae can be divided into:
Fast-acting nutrients – After application, small molecule nutrients that can be quickly utilized by algae in ponds are mainly mineral nutrients such as inorganic salts and trace elements, as well as nutrients such as amino acid hydrolysates.
Long-acting nutrients - after application, it has a certain sustained release effect, such as organic nutrients that are coated with sustained release and need to be further decomposed, and organic matter in aquatic bodies and dead animal and plant residues that rely on microbial decomposition to breed water bodies, etc., for aquatic organisms such as algae as nutrients.
From the perspective of nutrient supply, fertilizer water is essentially nutrient supply and balanced allocation. Therefore, whether inorganic fertilizers or organic fertilizers are used, their core value is what nutrients are provided and how these nutrients are configured.
Numerous studies have shown that different algae are more likely to become dominant algae in water bodies with different nutrient content. For example, when the actual nitrogen-phosphorus ratio in the farmed water body exceeds 10:1, the diatoms are prone to multiply; the nitrogen-phosphorus ratio is 3:1-7:1, or even close to 10:1, the green algae is prone to large-scale reproduction; but when the nitrogen-phosphorus ratio is close to 1:1, the toxic dinoflagellates and flagella are easy to reproduce.
It can be seen that if you blindly fertilize the water, it may be counterproductive.
The use of EM bacteria in aquaculture is widely recognized. However, the original solution fermented by EM bacteria is more expensive to use, and after long-term storage by manufacturers and distributors, the vitality of bacteria will also decline. In recent years, emmy bacteria have been more popular among farmers in the market. Farmers can expand their own cultivation after buying it back. The self-fermented EM bacterial liquid is low cost to use, and the number of fermented bacterial liquids is good. Then when choosing EM bacteria, we should pay attention to the quality of the strains. In general, there is one of the simplest indicators to determine the quality of a strain, the pH value. Because EM strains have the most lactic acid bacteria content, the low pH value of EM bacteria liquid indicates that lactic acid bacteria are abundant, which means that the overall EM bacteria activity is higher. In general, pH below 3.5 is considered a good strain, and if it can reach below 3, it is a particularly good quality EM strain.
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<h1 class= "pgc-h-arrow-right" > three, ammonia nitrogen, nitrite and inorganic fertilizer</h1>
1. The main sources of ammonia nitrogen are residual bait in water, metabolites of farmed animals, fertilizer and wreckage of aquatic animals and plants. In intensive ponds, artificial large amounts of bait and fertilization will also increase the nitrogen-containing organic matter in the cultured water.
Studies have shown that about 60% to 70% of the nitrogen in the feed is excreted into the water body. Therefore, the total nitrogen concentration in aquaculture water bodies is directly related to the feeding rate, feed protein content, protein digestion and utilization rate. Among the nitrogen-containing excreta of farmed animals, about 80% to 90% are ammonia nitrogen, such as the density of stocking is too large, and the biological metabolism in the farmed water body is vigorous, the amount of nitrogen-containing organic waste will increase, and the increase rate of ammonia nitrogen will greatly exceed the utilization limit of phytoplankton, which will lead to the accumulation of ammonia nitrogen in the water.
Of course, there is no need to say more about the harm of ammonia nitrogen. Note that ammonia nitrogen is present in water in both ammonia (NH3) and ammonium (NH4+), which is not toxic to farmed animals, while non-ionic ammonia nitrogen (NH3-N) is more toxic to farmed animals. In general, ammonia nitrogen control indicators, freshwater organisms to NH3 adaptation concentration range of 0.02-2.00mg / L, China's water quality standards stipulate that ammonia nitrogen is less than 0.5mg / L, "fishery water quality standards" stipulate: aquaculture production, the concentration of ammonia should be controlled below 0.02mg / L. In actual farming, it should not exceed 0.6 mg/L. In the shrimp farming process, the total amount of ammonia is required to not exceed 0.5 mg/L, and the ammonia nitrogen content is less than 0.2 mg/L.
2. Nitrite is mainly derived from nitrogen-containing organic matter in aquaculture water. In water bodies, it is first converted to ammonia nitrogen, then to nitrosite nitrogen, and finally to nitrosan nitrogen. When the nitrification process is blocked, it causes an increase in nitrite. The main reason for the high content of nitrite in the aquaculture water is the lack of dissolved oxygen in the pond water. In addition, the frequent use of fungicides causes the imbalance of microbial populations in the cultured water body to be destroyed, which is also the reason for the increase in nitrite content.
In order to ensure the safety of farmed animals, the nitrite in the water is generally controlled below 0.1 mg/L, and the content of nitrite in the aquaculture water quality should be controlled below 0.20 mg/L in the Fishery Water Quality Standard. In actual farming, the concentration of nitrite in shrimp ponds should not exceed 0.15 mg/L, and the concentration of nitrite in farmed animal ponds should be below 0.5 mg/L.
3. Use of inorganic fertilizer. It is clear that if the ammonia nitrogen and nitrite in the aquaculture water body are high, and then blindly use inorganic fertilizers containing nitrogen, it may lead to catastrophic consequences.
In general, the inorganic fertilizer used is called "quick-acting fertilizer". It mainly provides nitrogen, phosphorus, potassium, calcium and other macro elements, as well as some trace elements. In recent years, the concept of "carbon element" nutrition has been proposed, so a large number of carbon supplementation products have quickly filled the market.
Nitrogen: Nitrogen is one of the main components of proteins and is also an important component of chlorophyll, vitamins, alkaloids, and nucleic acids and enzymes. Nitrogen is one of the main nutrients of plants. Commonly used are ammonium nitrate, ammonium sulfate, calcium nitrate, sodium nitrate and the like.
Phosphorus: In general, the phosphorus content in ponds can meet the needs of aquatic animal growth. However, in the summer and autumn, phytoplankton breeds in large quantities, aquatic animals grow vigorously, and phosphorus is consumed in large quantities in ponds, often resulting in a significant reduction in phosphorus content. For example, the rational application of phosphate fertilizer to the pond during this period to improve the fertility of water quality is of great significance to improving the yield of aquatic animals. Commonly used inorganic phosphate fertilizers mainly include:
Calcium superphosphate, a gray-white powder, generally contains 16%-20% phosphorus, mainly water-soluble calcium phosphate, and the fertilizer efficiency is rapid and good;
Calcium superphosphate, phosphorus content of about 40%.
After these two phosphate fertilizers are applied to the pond, they generally only react within a few days. Later, the phosphoric acid is quickly adsorbed and fixed by the soil, thereby reducing the utilization rate of phosphorus by phytoplankton.
Potassium: Generally speaking, potassium deficiency is less common. If you need to supplement, the commonly used potassium fertilizers are: potassium sulfate, with a potassium content of 48% to 50%; potassium chloride, with a potassium content of about 50%; in addition, grass and wood ash can also be used.
Calcium: Calcium is very important for shrimp, because shrimp grow through molting, and each time it grows, it must be achieved through molting. One of the important components that make up shrimp shells is calcium. The appropriate ratio of calcium and magnesium makes the shrimp shell after molting, the new shrimp shell can quickly harden up, and its significance is very important to the shrimp, and it can even be said that it is "life-threatening".
Trace elements: This is often said to be a class of mineral elements with low content and significant physiological effects, such as copper, iron, fierce, zinc, magnesium, cobalt and so on. Its important biological utility is to make up many important proteins (such as hemoglobin), the core active substances of various enzymes. Therefore, it is common to mix or sprinkle in ponds during breeding to supplement "electrolytes". One of its roles is to provide shrimp with trace elements to ensure its normal physiological needs; the other is to supplement the trace elements in the farmed water body and ensure the nutritional needs of algae physiological metabolism.
In practice, as we all know, water exchange is the simplest and most effective way to reduce ammonia nitrogen and nitrite. The so-called "ammonia nitrogen reduction, nitrite reduction", in fact, is to increase the consumption of ammonia nitrogen and nitrite. This process requires the participation of other nutrients. Therefore, if phosphorus is insufficient and carbon is insufficient, the fastest way is to directly supplement inorganic matter more concisely.
Due to the imbalance of nutrients and the serious destruction of algal phases, many friends think of using microecological preparations to quickly convert ammonia nitrogen and nitrites in water into harmless nitrates. The use of microorganisms also needs to supplement other nutrients, such as carbon, phosphorus, etc., otherwise the growth and reproduction of microorganisms will also be hindered and the expected effect cannot be achieved.
Vitamins are essential for life maintenance, and humans also need to supplement a large amount of vitamins every day. Due to the structure of the human intestine, the digestive ability is strong, and the general vitamin is manufactured as ordinary granules. However, aquatic animals, such as crayfish, crabs and Penaeus vannamei, have shorter intestines and poor absorption capacity, so the smaller the particles of the vitamin, the easier it is to absorb. The latest foreign technology is to manufacture vitamins into nano-level particles, so that the absorption rate of aquatic animals is greatly improved. Secondly, the nano-level vitamin water solubility is good, whether it is a mixture or a splash of water, the effect is much better.
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<h1 class="pgc-h-arrow-right" > fourth, the use of inorganic fertilizer recommendations</h1>
In fact, if the content of ammonia nitrogen and nitrite in the aquaculture water body of shrimp ponds is high, it is really necessary to supplement some inorganic elements, such as phosphorus and carbon.
Personally, I believe that there is generally no shortage of phosphorus in shrimp ponds, and even a large amount of phosphorus. But why is it often emphasized that phosphorus supplementation should be done? As discussed earlier, when inorganic phosphorus is added to the pond, the utilization time of phosphorus is generally only a few days, and most of the phosphorus is "seized" by the pond sediment, forming insoluble phosphate, which precipitates at the bottom of the pond, and breeding animals, phytoplankton, etc. cannot be used.
Therefore, whether it is supplementing organic fertilizer or inorganic fertilizer, the key is to clarify the purpose of "fertilizer". Of course, if the content of ammonia nitrogen and nitrite in the aquaculture water body is high, organic fertilizer, nitrogen fertilizer, etc. are supplemented, that is, ammonia nitrogen and nitrite cannot be reduced, nor can a good algal phase balance be established.
Ammonia nitrogen and nitrite (including its precursors) can be used as nutrients for microorganisms and algae. Just to see how we can improve its "consumption utilization rate" to achieve the purpose of reducing ammonia nitrogen and nitrite, but also can establish a stable algal phase and bacteriophrenic phase, play a role in stabilizing water quality.
What we usually recommend is: bottoming + microbial agent + appropriate amount of inorganic elements or compound trace elements.
As for what kind of inorganic elements and trace elements are used, it is necessary to determine the actual aquaculture water body. However, there are some principles:
1, the principle of balance: in an ecosystem, the existence of various substances is a dynamic balance. Therefore, it is necessary to understand, master and use a variety of biological means to establish or improve the balance of algal phase and bacterial phase of aquaculture water bodies. As we have already discussed above, the actual proportion of nitrogen and phosphorus content in water bodies is different, which will lead to an increase in the reproduction of different algae, which should be deeply understood.
2, the principle of complementarity: inorganic fertilizer (fertilizer) is a quick-acting product, although the fertilizer water is fast, but the duration is short; organic fertilizer is a long-acting product, although the fertilizer water is slow, but the duration is longer. The reasonable combination of the two can achieve a good fertilizer and water effect that is fast and stable. Consideration must be given to the nutrients already in the pond (e.g. silt) and the nutrient structure and quantity of the base fertilizer applied, which requires testing and documentation. Do a good job of these basic work, and then know what to make up? How to make up?
3, the frequency principle: the use of inorganic elements, according to the weather conditions, flexible grasp of the amount and frequency of use. Light intensity, long light time more application, and vice versa, less application many times.
4, the compatibility principle: must take into account the compatibility of various elements of the taboo. Some elements cannot be used at the same time, otherwise some elements will lose their biological activity before they play a role, and cannot be used by microorganisms and algae in the farmed water. Some microorganisms also have antagonistic effects, and they must also be contraindicated in compatibility, or find ways to reduce their negative effects.