Soil Tilling and Drying

Aquaculture NCII

1. Soil Tilling and Drying

2. Objectives: Identify soil tilling and drying . Discuss its purpose in nursery pond operation.

3. Soil Tilling

4. - is simply turning over and breaking up the soil. Exactly how deep you till and how fine you break up the soil depends on your reason for tilling. To make the task of tilling easier, you can purchase or rent an engine-powered tiller from a garden supply center. These tillers are great for large areas, but if you only have a small area, try a cultivator fork or a deep spader or cultivator to loosen up compacted soil.

5. Why You Need to Till: Soil becomes compacted over a period of years from rain and foot traffic. Loosens and aerates the top layer of soil or horizon, which facilitates for the next operations Helps mix harvest residue, organic matter (humus), and nutrients evenly into the soil Mechanically destroys weeds . Dries the soil before seeding (in wetter climates tillage aids in keeping the soil drier).

6. Drying is a mass transfer process consisting of the removal of water or another solvent by evaporation from a solid , semi-solid or liquid .

7. The pond bottom should dry out until it cracks. This mineralizes the soil and helps in eliminating fish predators. Drying period of a minimum of two weeks or longer is ideal depending upon the weather and pond bottom conditions.

8. Purposes of pond drying 1. to eradicate fishpond pests, predators and competitors 2. to hasten the chemical decomposition of organic matters deposited so that nutrients will become available for the growth of fish food in the fishpond 3. to totally harvest the fish stock 4. to kill disease causing organism

9. Dried until the soil cracks or when it is firm enough to hold one's weight without sinking more than 5 cm on walking over the surface