Fertilizer is difficult
In the process of aquaculture, the quality and stability of water quality always affect the living environment of the animals farmed in the pond, and fertilizer water is a very important measure often taken in the aquaculture process, but in actual production practice, the problem of water fertilizer in the breeding pond is often encountered. The essence of fertilizer water is to cultivate beneficial algae, and the algae in the pond quickly grow to form a dominant group by absorbing nutrients in the breeding pond, but the growth of algae is generally affected by factors such as temperature, light, nutrients, and residual toxins in the water body.
What's the hard part?
What are the factors that cause the water to be infertile? Here are some factors for your reference.
1. Algae species
Aquaculture ponds, especially new ponds (after disinfection) have less algae, or the water source uses well water, groundwater and tap water and other water sources that lack algae species, the number of beneficial algae in the pond will be particularly small, less than enough to reproduce in large quantities, in this case, no matter how much fertilizer the farmer applies, the beneficial algae cannot be cultivated. It is recommended to select suitable algae species according to the conditions of the pond (south and north), pond conditions (seawater or fresh water; high pond or earthen pond) and culture species (shrimp, crab, sea cucumber, etc.), and first test the existing pond conditions, including water quality and biological conditions.
Second, nutrition
Take the water sample in the culture pond, and determine through microscopic examination that there is a certain amount of beneficial algae in the pond, but the water color is still not good enough, and the transparency is still high, which is likely to be the lack of nutrients or nutrients required for algae growth. For example, the cultivation of chlorella requires the nutrient elements of chlorella, and the cultivation of chydiaria requires the nutrient elements of chlorella, and the nutrients required by different kinds of algae are different, such as chlorella needs silicates and chlorella does not. Some researchers have done experiments on compound algae, selecting chrycobacteria, needle algae and chlorella three kinds of algae, after inoculation only add chlorella nutrients did not add chlorella and needle algae nutrients, the result of 2 days after the algae turned green, chlorella rapid reproduction, chrysochonos and needle algae did not grow much, algae have the original yellow-green turned green. Therefore, in this case, it is recommended to cultivate beneficial algae through targeted fertilization measures.
Third, water quality
Aquaculture water quality is not up to standard, algae is most suitable for growth of pH value of 6.5-8.5 between, too high and too low are not conducive to the growth of algae, can take the adjustment of pH of the substance, such as high pH can use acidic substances, low pH can be used alkaline substances to correct the pH value first. When the pH of the cultured water body is too low or the hardness is too large, it will also lead to insufficient carbon dioxide for algae to photosynthesis, affecting algae growth.
There are also farmers often overuse disinfectants and insecticides, such as bleach powder, quicklime and tea cakes and other disinfectant sterilization or other killing products, often lead to water body residue, heavy metal content exceeds the standard and algae and microorganisms are few, resulting in water difficulty fertilizer. It is recommended to do a good job of detoxification before cultivating algae, and in principle, do not use these things in the pond for 7 days before and after the fertilizer water.
Fourth, the climate environment
Many farmers react to low temperatures when fertilizer is difficult, which is the temperature adaptability of algae, which is due to the fact that many algae enter the dormant period in the low temperature season, and it is naturally more difficult to fertilize water under such low temperature conditions. So when it is low, is it completely unable to fertilize the water? The low temperature season is not without algae, and there are more than 10 common dominant species under ice, of which chlorella and small ring algae are among them, and can solve the problem of hypoxia under ice. However, the low temperature season fertilizer water, not only fertilizer water is difficult, fertilizer water cost will also increase, in the season when the temperature is suitable for rainy days fertilizer water effect will also be discounted, and then encounter continuous rain and other unstable weather conditions, insufficient light, algae growth and reproduction rate will be slower. Therefore, LuHao suggests that in order to avoid low temperature fertilizer water and rainy days, it is best to carry out fertilizer and water cultivation work under three or four sunny days.
For the case of insufficient light, in the breeding of large water bodies, you can choose to be suitable for low light algae, such as the small ring algae in the diatom is suitable for low light, or choose the compound algae culture, you can also use the light to reproduce the algae indoors, and then use it in the outdoor pond.
5. Zooplankton
Because algae are the best food for zooplankton, if there are too many zooplankton in the water body, such as rotifers, brine worms and copepods, etc., the reproduction is too fast so that the algae have not yet developed and grown and have been swallowed, and the beneficial algae cultivated cannot form a dominant population, resulting in thin water quality and difficulty in fertilizer. Lu Hao recommends that farmers carry out microscopic examination before cultivating algae, if they find that there are many zooplankton, they should take physical methods or chemical methods for corresponding control, such as the use of light trapping or pump pumping, filtered out rotifers, branches or copepods can also be used as bait for farmed animals, or in the evening along the edge of the pool to apply insecticidal drugs to kill locally, especially when the whole pond can be killed during the day, pay attention to the dose, observe after taking the drug, in order to take corresponding measures in time. Farmers can take corresponding measures according to specific conditions, and chemical methods should pay attention to detoxification.
Sixth, harmful algae outbreaks or excessive aquatic weeds
A large number of harmful algae outbreaks in the pond, such as microcystis, naked algae, moss and too much aquatic weeds, etc. are not treated, they will multiply in large numbers to occupy the ecological niche of the entire pond, inhibit the reproduction and growth of beneficial algae, and if not controlled, it will eventually seriously affect the growth of farmed animals. For example, if the submerged plants in the crab pond (Yile grass, moss, etc.) are too much and too thick, they will compete with the algae for nutrition, resulting in the algae not being able to reproduce, but the grass is growing better and better!
7. Suspended solids
Too much suspended solids in the water body will reduce the transparency of the water, weaken the intensity of photosynthesis, and the light and nutrients of phytoplankton growth will be affected, resulting in difficulties in fertilizing water. For example, in the crayfish farming pond, there are many wild fish or crayfish in the water, especially when the feeding is insufficient, the activity of the crayfish increases and constantly stirs the bottom of the pond, making the water turbid, low transparency, and algae cannot survive. Because the composition of suspended solids is different, the impact on algae is also different, Luhao suggested that farmers and friends according to the composition of specific suspended solids to treat first, you can choose a good adsorption of substances to first adsorb suspended solids, adsorption after settling to the bottom of the pond, and then use microorganisms to degrade, improve water quality and then cultivate algae. Lu Hao recommends increasing the amount of algae seed and nutrients when cultivating algae.
Analyze the causes and take targeted measures
In the process of breeding, when encountering the situation that water and fertilizer cannot be improved, do not rush to apply various fertilizer and aquatic products, it is recommended that everyone take targeted measures according to the characteristics of local aquaculture waters, their own pond conditions and pond conditions. For example: the lack of microorganisms in the water body, organic matter can not be decomposed into small molecules of polypeptides for algae absorption and utilization; the bottom of the formation of a pond with mud skin, the nutrients in the water body are absorbed by the mud skin; the pond itself is poor in fertilizer retention and fertilizer storage capacity, such as the water level is too shallow, the soil absorbs too much fertility, resulting in too short water fertilizer efficiency; the new pond is seriously infiltrated or lack of minerals, the water quality is unstable and so on. The above reasons are typical reasons for the difficulty of fertilizer water in common ponds, and we can take corresponding remedial measures for specific reasons and then fertilize the water.
In short, there are many practical situations in the fertilizer and water problem, which need to be analyzed specifically and specifically.