Why quicklime is mostly used in soils? Why it is not used during culture?

Hello everyone:

Today we will see about reaction of quick lime in soil and it's importance in aquaculture. Instead of lime other materials also used such as dolomite etc. Particularly we see about quick lime.

Burnt lime(Cao)

If we treated burnt lime with water, it forms calcium hydroxide ( hydrated lime or slaked lime). Slaked lime is prepared by hydration with water.

Quick lime (Cao):

   It is also called as burnt lime or unslaked lime. It is named as burnt lime because of its method of  production.

    Everyone know that before going for stocking, we have to do liming and also heard that all persons use quick lime to the soil preparation. I am right?

    If it is a new pond or previously cultivated pond, anything it may be. But liming is important. If it is previously cultured pond means, there is lot of sludge,it is in acidic conditions and contains toxic ions, sulfur compounds. We want to correct it.

     Generally clayey pond bottom have acidic conditions with lot of Hydrogen and Aluminum ions. This cause the pH of the soil in lower level.

Lime has a reacting capacity with acids. By the reaction they neutralize the acidity. Hydroxides of lime produce carbonates by the reaction with carbon dioxide. It increases pH and alkalinity and hardness.

     If quick lime applied to the soil, it replace the bad ions present in the surface of the soil and make the soil free and increase the load bearing capacity of the soil.

Example: clayey soil have some of silica, alumina. After application of lime, Ca present in the lime reacts with these silica and alumina, it forms (Ca silicate hydrate) and (Ca aluminate hydrate.) These compounds increase the soil strength.

Calcium oxide is more reactive compared to other lime. Calcium oxide produce lot of heat when it applied with water and also suddenly increase the pH compared to other lime. If we applied this quick lime into the cultured pond means it may cause any stress to the cultured organism due to its heat producing capacity and sudden increasing in pH. So we use the Quick lime in soil only. Quick lime have high melting point. 

Lime increases the pH, alkalinity, hardness and calcium present in the lime promotes plankton production.

Note: Low pH leads to phosphorus deficiency in water.In low pH, phosphorus is tightly bound to bottom soil by irons and Aluminum. It causes the nutrient deficiency to plankton. By application of lime we can overcome this. Phosphorus is the limiting nutrient in freshwater.

Application rate of lime to the pond is generally based on the pH of the soil and Neutralizing efficiency of the lime. In water lime dissolves slowly. Lime also disinfect the harmful microorganisms present in the soil. By sudden increase in pH, microorganisms cannot able to tolerate and die. But in aquaculture, some of the researches told , we cannot completely kills vibrio by lime application. But we can control it. Lime is an disinfectant, it kills parasites and other small organism present in the pond soil. The reaction of lime also depends on its fineness and it's size. Limestones are not used in water because of its slow solubility. After application of lime in soil, it will take sometimes to complete the reaction. It also depends on the lime efficiency.

White is the colour of this lime . If we observed any other colour like brownish etc..We can conclude that there is a impurities in this lime. Early morning is better for application of lime. At this time the pH also low. 

                       Thank you 😊.