Observation

 

This question was popular among the candidates, and there performance was good.
In part (a), majority of the candidates could not state the uses of urea and its advantages over cow dung.

In part (b), majority of the candidates were able to list three sources of specimen C in fish culture and also could state three parameters of specimen C that should be monitored during fish culture.

The expected answers include:

(a) (i) Uses of specimen A (Urea)
Specimen A (urea) is use to:
-fertilize pond water
-promote phytoplankton/plankton growth in ponds
-boost primary productivity
(ii)Advantages of specimen A (Urea) over specimen B (Cow dung)
- chemical constituents are high/concentrated/complete/more
- it releases nutrients faster
- not bulky
- does not give offensive/bad odour
- does not deplete dissolved oxygen/oxygen in pond
- easy to apply/handle
- does not pollute pond water
- the chemical constituents are known/constituents are in right proportion
- it is hygienic/not messy.
(iii)Methods of applying specimen B (Cow dung)
- broadcasting/spreading
- heaping/stacking/spot
- platform/dry bottom
- bagging/sack.

(b) (i)Sources of specimen C (pond water)
- spring
- well
- bore hole
- river
- stream
- rain
- pipe borne/tap water

(b) (ii)Parameters of specimen C (pond water) that should be monitored in a pondduring fish culture
- pH/acidity/alkalinity
- dissolved oxygen
- turbidity / transparency
- nitrite
- nitrate
- ammonia
- temperature
- conductivity
- depth
- iron
- sulphide/sulphite
- hardness