Lesson Notes By Weeks and Term - Senior Secondary School 1

Date: 23^rd - 27^th of January 2023

Class: SSS 1

Term: 2^nd Term

Week: 3

Subject: Agricultural Science

Topic: Crop Husbandry

Duration:45 minutes

Teaching Aid: A chart

Reference Books: Essential Agricultural Science for Senior Secondary Schools by O.A Iwena (pg 139-142)

Comprehensive Certificate Agricultural Science for Senior Secondary Schools by L.A et Al (pg244-248)

Behavioural Objectives: By the end of this topic, students should be able to

1. Discuss the husbandry of yam
2. Discuss the husbandry of cassava

Presentation I

Step 1: Teacher revises last topic

Step 2: Teacher introduces and explains new topic

Step 3: Teacher writes note on the board

Step 4: Teacher evaluates students

Step 5: Teacher marks students' notes and give assignment

Previous knowledge: Students have been taught crop husbandry

Content

YAM (Dioscorea spp)

Yam belongs to the family Dioscoreaceae. It is a root and tuber crop popularly grown in West Africa and it is rich in carbohydrates.

Land preparation: Cutlass is used to clear the bush or vegetation and heaps, ridges or mounds are made with hoe. It can also be done by ploughing, harrowing and ridging mechanically.

Varieties or Cultivar: Important varieties include:

1. Dioscorea rotundata – white yam.
2. Dioscorea alata – water yam

• Dioscorea bulbifera – aerial yam

1. Dioscorea cayenesis – yellow yam
2. Dioscorea domentorum – bitter yam.

Climatic and soil requirement: Yam requires a temperature of 25^oC – 30^oC; rainfall of between 100cm – 180cm per annum; abundant sunshine and; a well drained sandy-loamy soil, rich in humus.

Method of propagation/propagation

Materials: Yam is propagated by the following materials: yam sets, yam seeds or yam minisetts.

Seedrate: One seed yam or sett per hole; three to five tones of seed yam per hectare is required.

Planting dates: Early yam is planted between November and December, while late yam is planted between March and April.

Planting: Open a hole on the heap. Place one yam sett inside with the cut surface turned upward and slantly placed at an angle of 45^o before covering it with soil. The cut yam sett should be dried under the sun and dusted with chemicals, e.g, addrin dust, before planting. This prevents rottening and past attack of the sett.

Spacing: Spacing is 90cm x 100cm, while yam mini-setts is 25cm x 100cm. sprouting occurs three to six weeks after planting.

Cultural practices

1. Mulching: This is the covering of the heaps or ridges with dry leaves to reduce soil temperature, conserve soil moisture and prevent rottening of yam setts.
2. Regular weeding: This should be done regularly to control pests and reduce weed competition with crops for nutrients.

• Application of fertilizer: Apply 200kg (four bags) of N.P.K. fertilizer per hectare three months after planting by ring method.

1. Staking: The yam should be staked with strong sticks or bamboo. It ensures adequate exposure of the leaf surface to sunlight and increase yield.
2. Training of vine: This is done regularly after staking to ensure even spreading and neatness of the vines to receive sunlight.

Maturity period: Yam matures in 8-12 months after planting.

Harvesting: Dig the soil gently with cutlass to remove tuber from the soil

Process: Yam tubers are processed into yam powder or flour or consumed locally.

Storage: Yam tubers are stored in bans. It can also be stored in form of yam flour and in dried peeled yam tubers.

Pest of Yam

1. Yam tuber beetle: The beetles makes holes on tubers, resulting in low tuber marketability

Control: (i) apply insecticide like BHC at planting. (ii) Dust yam sett with aldrin dust (iii) Practise crop rotation

2. Yam shoot beetles: Young larvae cluster on vine tips. Adults feed on yam leaves and cause vine to die or defoliate.

Control: (i) Spray yam plant with insecticides, e.g., BHC (ii) by hand picking (iii) dust with chemical like agrocide 3 powder.

3. Rodents: Rat and rabbits eat up tubers.

Control: Set traps to catch the rodents

Disease of Yam

1. Yam mosaic disease: It caused by a virus which is transmitted by a piercing and sucking insect

Symptoms: Symptoms include a mosaic pattern and chlorosis of leaves. It causes stunting of affected plant.

Control: (i) Grow resistant varieties and (ii) Spray with insecticides.

2. Yam rot: It is caused by bacteria which are spread by splashes of rain and insects.

Symptoms: Liquid oozes out from infected tuber. White-brown emits with pungent odour.

Control: (i) Destroy all affected yam. (ii) Apply aldirn dust. (iii) Practise crop rotation

3. Yam leaf spot: It is caused by a fungus, (cerospora spp) which is spread a wind.

Symptoms: symptoms include dead spots on the leaves

Control: Spray yam plants with appropriate fungicides.

CASSAVA (Manihot spp)

Cassava just like yam, is a root and tuber crop. It has underground root which can be consumed by man and livestock animals after processing. It has other advantages over yam, in that it can grow in relatively poor soil and in low rainfall area. The root is also rich in carbohydrates.

Land preparation: The bush is cleared with cutlass. Stumping is done and hoe could be used to make heaps or ridges. Ploughing, harrowing and ridging can also be done mechanically.

Varieties/cultivars: There exist two main varieties: sweet cassava (Manihot palmate) and bitter cassava (Manihot utilissima). The latter contains some poisonous hydrocyanic acid in its roots.

Climatic and soil requirement: Cassava requires a temperature of 21^oC-35^oC, rainfall of 150cm – 200cm, a well-drained, rich friable, loamy soil. It can also grow in poor soil.

Method of propagation: By stem cuttings which are planted from March to September.

Planting date: Cassava sticks or cutting are planted from March to September.

Spacing: Cassava is spaced 1m by 1m

Planting: A stem cutting of 25-30cm long is pushed into the ridge or heap slantly at an angle of 45^o and of it buried. Sprouting occurs 7-14 days later.

Cultural practices

1. Weeding: This is done regularly.
2. Fertilizers application: Apply 250kg/ha of N.P.K fertilizer four to six weeks after planting.

Maturity Period: This occurs between 8-15 months depending on varieties.

Harvesting: Use cutlass to remove some soil and pull the stem gently so that the tubers are pulled along or, use cassava puller.

Processing: Cassava is processed into garri, foofoo, flour or livestock feed.

Storage: Cassava is stored in processed form in sack as garri or foofoo.

Pests of Cassava

1. Variegate grasshopper: Adults and nymphts eat up the leaves and young stems of plant (complete defoliation)
2. Rodents: Rodents, like cane rats, bush rat and grasscutter, dig the ground and eat up the tubers.

Control: (i) Trapping (ii) Shooting with gun (iii) Wire fencing round the farm

Disease of Cassava

1. Cassava mosaic disease: It is caused by virus which is transmitted by a piercing and sucking insect (white flies)

Symptoms: Symptoms include vein clearing and distortion of the leaves and stunted plants

Control: (i) Grow resistant varieties (ii) uproot and burn infected plants (iii) use disease free planting materials

1. Bacteria blight: It is caused by bacteria which are transmitted by infected cuttings.

Symptoms: These include angular, water soaked area of discoloured leaf tissue, blighting, wilting and reduction in yield.

Control: (i) Use resistant varieties. (ii) Use clean and disease-free stem cuttings.

• Angular leaf spot: It is caused by a fungus. Symptoms include spores which produce pale, brownish colour on affected leaves.

Control: (i) Spray with fungicide, e.g., Bordeaux misture.

Evaluation: what are the varieties of yam and cassava?

Assignment: What is the essence of staking yam