AGRICULTURAL SCIENCE CLASS NOTES: PASTURE AND FORAGE CROPS

Level: S S 1 (Senior Secondary School 1) Subject: Agricultural Science Topic: Pasture and Forage Crops Curriculum Focus: Nigerian National Curriculum for Senior Secondary Schools

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1. COMPREHENSIVE CORE CONCEPTS

Definition and Meaning

In the study of Agricultural Science, Pasture refers to a piece of land covered with grass and other low-lying plants, which is specifically managed for grazing livestock such as cattle, sheep, and goats. Forage Crops, on the other hand, are specific plants (grasses or legumes) grown and harvested intentionally to be fed to livestock as fresh fodder, hay, or silage.

The relationship between pastures and livestock is the foundation of animal husbandry. Without high-quality forage, animals cannot produce the milk, meat, or wool that humans depend on. In Nigeria, the management of pastures is particularly important due to the distinct wet and dry seasons, which affect the availability of green feed throughout the year.

Classification of Forage Crops

Forage crops are primarily classified into two main botanical groups: Grasses and Legumes.

A. Grasses (Gramineae Family)

Grasses are the primary source of energy (carbohydrates) for livestock. They are characterized by narrow leaves, parallel veins, and fibrous root systems that help prevent soil erosion.

• Common Examples in Nigeria:
  • Guinea Grass (Panicum maximum): A very popular perennial grass that grows in bunches and is highly palatable to livestock.
  • Elephant Grass (Pennisetum purpureum): Also known as Napier grass, it is tall, robust, and often used for "cut-and-carry" feeding systems.
  • Giant Star Grass (Cynodon nlemfuensis): Known for its rapid spreading ability via underground stems (rhizomes) and surface runners (stolons), making it excellent for erosion control.

B. Legumes (Leguminosae Family)

Legumes are the primary source of protein and minerals for livestock. They have the unique ability to "fix" nitrogen into the soil through nodules on their roots, which improves soil fertility.

• Common Examples in Nigeria:
  • Centro (Centrosema pubescens): A climbing legume that mixes well with grasses.
  • Stylo (Stylosanthes guianensis): A hardy legume that thrives even in poor soils and provides high-quality protein.
  • Puero (Pueraria phaseoloides): Also known as Tropical Kudzu, it provides excellent ground cover and high-quality feed.

Types of Pasture

1. Natural Pastures (Rangelands): These are uncultivated lands where native grasses and shrubs grow naturally. In Nigeria, the Northern Savanna belts are vast natural pastures where nomadic herders graze their cattle. While free, these pastures often lack high nutritional value during the dry season.
2. Established (Artificial) Pastures: These are pastures deliberately planted and managed by farmers. The farmer selects specific seeds (often a mix of grasses and legumes), prepares the land, applies fertilizers, and manages grazing to ensure maximum productivity.

Factors Affecting Pasture Distribution and Productivity

Several factors determine where and how well pastures grow:

• Climatic Factors: Rainfall is the most critical factor. Adequate sunlight and temperature are also essential for photosynthesis.
• Soil Factors: The fertility, texture, and pH of the soil determine the types of forage that can survive. For example, legumes prefer well-drained soils rich in phosphorus.
• Biotic Factors: This includes pests, diseases, and human activities like overgrazing, which can destroy a healthy pasture.

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2. REAL-WORLD APPLICATIONS

Scenario A: The Backyard Goat Farmer

Imagine a family in a Nigerian suburb keeping three goats. Instead of letting the goats roam the streets where they might eat trash or be hit by cars, the family plants a small "fodder bank" of Elephant Grass and Stylo behind their house. By using a "cut-and-carry" system, they ensure their goats stay healthy, grow faster, and produce richer manure for their vegetable garden.

Scenario B: Soil Conservation on a Sloping Farm

A farmer in a hilly area like Jos or Ekiti notices that heavy rains are washing away his topsoil. To stop this, he plants Giant Star Grass across the slopes. The thick network of roots holds the soil together, while the leafy cover protects the ground from the direct impact of raindrops. This is an application of pasture crops for Environmental Protection.

Scenario C: Beekeeping and Pollination

A student starts a small beehive project. By planting legumes like Centrosema near the hives, the student provides the bees with a steady source of nectar and pollen. The legumes benefit from the bees' pollination, and the bees produce high-quality honey.

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3. PRACTICAL APPLICATIONS (Step-by-Step Guides)

How to Establish a Small Pasture Plot

1. Site Selection: Choose a well-drained area with access to sunlight.
2. Land Preparation: Clear the weeds. Dig the soil to a depth of about 15cm to create a loose seedbed.
3. Seed Selection: Obtain healthy seeds or cuttings. For example, Elephant grass is usually planted using stem cuttings (culms), while Stylo is grown from seeds.
4. Planting:
   • If using seeds, sow them thinly in rows.
   • If using cuttings, bury them at a 45-degree angle with at least two "nodes" (joints) underground.
5. Fertilization: Apply NPK fertilizer or organic manure to help the young plants establish.
6. Weed Control: Hand-pull weeds for the first 8 weeks until the forage crops are tall enough to shade out the competition.

Preservation: Making Hay (Sun-Dried Forage)

To ensure livestock have food during the dry season, farmers make hay.

1. Cut: Harvest grasses (like Guinea grass) just before they start flowering (this is when they have the most nutrients).
2. Dry: Spread the grass out in the sun on a clean, dry surface.
3. Turn: Turn the grass over every few hours to ensure even drying.
4. Store: Once the grass is "crispy" but not brittle (usually 2-3 days), tie it into bundles (bales) and store it in a dry, ventilated shed.

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4. SUGGESTED HOME PROJECTS

Project: The "Pasture Herbarium" (Plant Identification)

• Goal: To identify and preserve common forage plants in your community.
• Materials: Old newspapers/magazines, heavy books, cardboard paper, glue, and clear tape.
• Procedure:
  1. Walk around your neighborhood or school farm and collect 5 different types of grasses and 3 types of legumes.
  2. Place each specimen between sheets of newspaper and press them under heavy books for 5-7 days until they are completely dry.
  3. Carefully glue each dried plant onto a piece of cardboard.
  4. Label each plant with its Common Name, Botanical Name (if known), and whether it is a Grass or a Legume.
  5. Write one benefit of that specific plant (e.g., "Good for erosion control").

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5. LIFE SKILLS INTEGRATION

• Resource Management: Learning to grow and preserve forage teaches students how to manage resources efficiently, preparing for "lean times" (like the dry season).
• Environmental Stewardship: Understanding how grasses prevent erosion and how legumes improve soil health fosters a sense of responsibility toward protecting the Earth.
• Career Connections:
  • Rangeland Manager: Managing vast areas of land for grazing.
  • Animal Nutritionist: Formulating diets for livestock using different forage combinations.
  • Entrepreneurship: Producing and selling baled hay or silage to cattle farmers during the dry season is a profitable business in Nigeria.

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6. ASSESSMENT THROUGH APPLICATION

1. The Farm Consultant Task: Imagine a local farmer has a cow that looks thin and weak. The farmer only feeds the cow dry corn stalks. Based on what you've learned about Grasses and Legumes, write a 3-step recommendation for the farmer to improve the cow's health.
2. Visual Identification: (Teacher displays 5 different plants). Identify which are legumes and explain the "visual clues" (e.g., leaf shape, presence of pods) you used to identify them.
3. The Drought Plan: Create a one-page "Dry Season Feeding Plan" for a sheep farm. Explain how you would use Hay and Silage to keep the animals fed when there is no rain.
4. Field Mapping: Draw a simple map of your school compound. Identify three areas where forage crops could be planted to prevent soil erosion and label the type of grass you would recommend for each spot.

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7. STUDENT REFLECTION QUESTIONS

• Why is a mixture of grass and legumes better for a goat than a pasture consisting only of grass?
• How does the "Nitrogen-fixing" ability of legumes save a farmer money on fertilizers?
• If you were a nomadic herder, what challenges would you face in Nigeria today, and how could "established pastures" help solve those challenges?
• Look at the soil around your home. Is it bare or covered in grass? If it is bare, what specific forage crop from your notes would you plant there, and why?