Site Selection for Growthout

 Site Selection for Growthout

  We should study where the local what happened before (flooding, landslide, erosion and etc.) We should avoid a woody weed, trees and closing the building. Topography is the features of the land surface and refers to mountains, valleys, rivers or craters on the surface. The most important of inlet and outlet for growthout pond is depend on topography. So, we should study and choose the topography.

  Slope of topography should be 0.5 to 1% and more than 5% shouldn't choose for growthout pond because of destruction of soil and the high the cost of construction. We should be choose soil type contain of mud: sand: ooze (60: 10: 30%) and shouldn't choose sandy soil because it cause a leakage of water put about 3ft into the pond, the next day leak about 1ft out of the pond.

  As the sandy soil pond easily breaks the dike of pond by erosion. So, we need to mend the dike of pond again and again. As the sandy soil we lay the liner all over the pond. So, we spend our money a lot on it.

  Before we start, we should consult with the local authority whether send the soil sample or study the history of that locals. As the former I say, water resource is very important for aquaculture. Water resource is from rivers, brooks, irrigation and underwater (tubewell). In generally, irrigation and tubewell are better than others we guess.

  We shouldn't directly use from rivers, brooks and must take the reservoir and use from it because it can carry the chemical residues, pesticides and turbidity (ooze). Next  underwater (tubewell), we have to care to use tubewell because it can less Dissolve Oxygen (D.O) but more chemical toxic (iron and etc.,..). We construct a canal from tubewell to reservoir. As it pass through the canal to reservoir absorb O2 from air and neutralize chemical toxic.

  Next one, we must consider the climate of the selected location. The climate is rainfall, heat (temperature) and wind speed. These are directly or indirectly related to our aquaculture system. For example, we should study and think how much rainfall is throughout the year and do we need to wall with plastic our pond which cultured catfish, snake head fish and etc. 

  And then, heat (temperature), the summer is the hottest season among of the three season in Myanmar. We often hear and see that it happen motalities of fish in summer. We need to check how much reach maximum and minimum temperature of our pond in summer. We should do too that other countries are daily feeding the feed according to the temperature (28 - 30°C). We should study and measure the wind speed by anemometer throughout the years to know the north wind or the south wind in monthly. So, we can construct the growthout pond against the wind speed, so we can protect the dike devastation as the happened by wind.

  Next one, we need to clear natural vegetations ( for exp., mango, raintree, tamarind, wild plants and etc.) near our pond. The cost of clear these wild plants, expend more than think. Because there are so many of these plants do not get sunlight or wind. So, the dissolved oxygen (D.O) may be decreases and can affect our pond. When a large tree is cleared, the rest of its roots rot and seep water in and out of the pond. Therefore, we should avoid such places. If we have chosen according to the situation, we should consult with knowledgeable people and then do something like this.

  Another thing is that the type of soil where mangrove grows acidic areas. Because it is acidic, it may become difficulties and obstacles for our aquaculture business in the long term and the costs can increase. Also, if we are going to clean up this mangrove, we should consult with knowledgeable people as the mangroves are protected by environmental protection.

  In addition, soil is composed of (3) types of minerals. Those are physical properties, chemical properties and biological properties. Physical properties will include soil color, topography and soil compretidy. Five types of soil color are black, blue, yellow, brown and white. 

  If we choose, we should only choose yellow and brown because these soil are rich in oxygen. White color is acidic and black and blue are Hydrogen Sulphate (H2S) and Ammonia (NH4). Therefore, if we choose soil color, we should only choose brown & white. Former, I said about topography. We should check compretidy because the mud can crack when it dry by sun. So, it may be leak in and out of the pond.

  And chemical property, we don't choose soil pH less than 4.5 and being conductivity. If you choose in condition, should consult with technicians. And TDS (Total Dissolved Solid), we should measure TDS (Magnesium, Zinc, Potassium). 

  And biological properties, we have to choose soil type contain of bacteria, insects and mollusks. It can maintain soil and water qualities. Only then, we should choose this type of soil.

Thank you so much.

 Myint Zaw

Aquaculture Technician