Page 121 - Agriculture_Form_3

Agriculture for Secondary Schools

2. Look for signs of nutrient deficiency, such as yellowing leaves or poor growth.
3. Suggest simple ways to improve the soil condition, and share with your
teacher before applying in the school field.

4. Record your observations and what you have learnt from this activity in your
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portfolio.

Exercise 7.4

1. In a school plot where no compost was added, cowpea plants show yellow
leaves and weak growth. Identify the likely cause, and suggest techniques to
improve the soil using locally available materials.

2. Two plots were ploughed at different times; one just before the first rains when
the soil was still very dry, and the other after the rains had begun, leading to
differences in plant growth. What factors might explain these differences?

Management of weeds in cowpea fields
Weed management in a cowpea field is most important during the early growth
stage, within the first two weeks after planting. At later stages weed effect may
not be significant due to the covering nature of the crop. Weeding is done by hand
hoeing, pulling or by spraying herbicides, depending on the scale of production
and affordability of the technology. Where applicable, practising mulching helps
to reduce weed growth. Mulches also help to retain the soil moisture and reduce
erosion. A clean field helps cowpeas to grow well and use soil nutrients more
effectively.

Activity 7.6

Manage weeds in your school cowpea field by carrying up the following tasks:
(a) Identify different weed types found in the field (their local names, how they
affect cowpea growth, and how they can be effectively managed).

(b) Divide the field into small plots for experiment. In each plot, try a different
weed control method such as hoeing, hand-pulling, mulching, or herbicide
(only under supervision). Leave one plot without weeding to serve as control
plot.

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