Page 56 - Agriculture Form Two

Agriculture for Secondary Schools

Using chemical fertilisers, smallholder farmers can increase their cassava yields
from about 10 to 16 tonnes of fresh roots per hectare. In Tanzania, most farmers
do not apply fertiliser to their farms. It is recommended to use the following four
key principles when using fertiliser in cassava production:
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(a) the correct type of fertiliser;
(b) right rate of application;
(c) right timing of application; and
(d) the correct method of application.

A compound fertiliser with the composition of nitrogen (N), phosphorus (P), and
potassium (K), alongside micronutrients such as boron and zinc, is advised for
increasing cassava yields. Other fertilisers such as urea, single superphosphate
(SSP) or triple superphosphate (TSP) and potassium chloride (KCl, also known
as muriate of potash) can be used. The amount of fertiliser to be applied should
be based on soil test results and applied in three phases: One-third of the total
quantity should be applied 4-6 weeks after planting. The second application
should be done 10–12 weeks after planting, followed by a third application 16–
20 weeks after planting. Consult agricultural experts about the type, rate, timing,
and method of fertiliser application based on the nutrient status of the field soil.

Activity 3.4

1. Through farm visits, market survey, library, and internet search:

(a) Identify different types of organic and inorganic fertilisers that are
recommended for cassava production; and
(b) Indicate the amount and the right time of application for each.

2. Under the guidance of your teacher, choose the right fertiliser and apply it to
the cassava plants you have established.
3. Keep observing and recording the progress of the crop plants in your portfolio.

Pest management
Cassava is affected by various pests that reduce its yield and quality. Significant
cassava pests include weeds, viruses, cassava mealybugs, green mites, variegated
grasshoppers, and whiteflies. Effective management strategies against these pests
can improve productivity and quality.

48 Student’s Book Form Two

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Agriculture form 2.indd 48