Agriculture Science Topic 3 🌾

Crop Production 🌿

Types of Crop Plants 🌱

Crop plants can be classified based on their life cycle into three main categories:

• Annuals 🌼: These crops complete their life cycle from seed to seed within one year. Examples include:
  • Groundnuts 🥜
  • Maize 🌽
  • Millet 🌾
  • Cotton 🌸
  • Sunflower 🌻
• Biennials 🌱: These plants grow in the first year and produce flowers and fruits in the second year before they die. Examples include:
  • Carrots 🥕
  • Turnip 🥔
• Perennials 🌳: These crops live for more than two years and continue to grow and produce flowers and fruits for several years. Examples include:
  • Mangoes 🥭

Morphology of Plants 🌿

1. Roots 🌱

Types of Roots:

• Taproot System 🌳: Consists of a single main root that grows straight down in the soil with smaller side roots branching out. This is common in dicotyledonous plants e.g. beans.
• Fibrous Root System 🌾: Contains multiple roots arising from the same point with side roots branching out. This is common in monocotyledonous plants e.g. maize and finger millet.

2. Stem 🌿

Functions of the Stem:

• Supports leaves, flowers, and fruits to enable them to function properly 🌼.
• Conducts mineral salts and water from the soil to other parts of the plant 💧.
• Facilitates pollination by holding the flower in a favorable position 🌸.

3. Leaves 🍃

Functions of Parts of the Leaf:

• Lamina 🌿: Contains chlorophyll to absorb light for photosynthesis ☀️.
• Veins 🌱: Support the lamina, conduct nutrients and water, and collect food 🍽️.
• Midrib 🌿: Supports the lamina and helps in the transport of nutrients 🚚.
• Stalk 🌾: Transports food from the leaf to the stem and nutrients from the stem to the leaf 🌱.

4. The Flower and Pollination 🌸

Structure of the Flower:

• Stamen 🌼: Male part of the flower consisting of the anther and filament.
• Carpel 🌷: Female part of the flower consisting of the stigma, style, and ovary.

Seed Structure 🌱

External Parts of the Seed 🌾

• Maize Seed (Monocot 🌽)
• Bean Seed (Dicot 🥫)

Internal Parts of the Seed 🌱

• Testa 🛡️: Protects the seed from pests and diseases.
• Embryo 👶: Contains the radicle and plumule.

Hybrid Seeds 🌱

Advantages of Using Hybrid Seeds 🌟

• Increased crop yields 📈.
• Improved resistance to pests and diseases 🦠.

Disadvantages of Using Hybrid Seeds ⚠️

• Cannot be replanted from previous crops; must be bought each season 💰.
• Expensive to purchase 💸.

Vegetative Propagation 🌱

Types of Natural Vegetative Propagation 🌿

• Suckers 🌱: New growths at the base of the parent plant (e.g. bananas 🍌).
• Bulbs 🧅: Storage organs that produce buds (e.g. onions).
• Stem Tubers 🥔: Swollen stems with buds (e.g. potatoes, yams).

Methods of Artificial Propagation 🌱

• Budding 🌱: A bud is taken from one plant and grafted onto another.
• Grafting 🌿: Involves joining the cambium layers of two different plants.

Crop Distribution and Growth in Zambia 🌍

Difficulties Limiting Crop Growth ⚠️

Several factors can limit the growth of certain crops in various regions of Zambia:

• Climate ☀️: Crops like maize and millet require high rainfall; low rainfall leads to reduced yields.
• Soil Quality 🌱: Acidic and infertile soils limit crop yields.

Soil Characteristics for Crop Production 🌱

• Well-Drained 💧: To prevent waterlogging.
• Good Aeration 🌬️: Allows roots and soil organisms to breathe.

Factors Affecting Crop Growth 🌱

Light ☀️

Essential for photosynthesis, the process by which plants make food.

Water 💧

Plays a crucial role in dissolving nutrients for absorption and cooling the plant through transpiration.

Weed Control Methods 🌿

Mechanical Control ⚙️

• Hand weeding, hoeing, and cultivation.

Chemical Control 🧪

• Using herbicides that attack weeds through contact, translocation, or soil application.

Pest and Disease Control 🦠

Signs of Pest Attack ⚠️

Holes in leaves, yellowing, wilting spots, and reduced crop yield.

Crop Pest and Disease Prevention 🛡️

• Practice crop rotation and timely planting 🌱.
• Use pest-resistant seed varieties 🌾.

Harvesting Techniques 🌾

Maize 🌽

Harvest by hand or using a combine harvester when cobs are dry with moisture content below 12%.

Groundnuts 🥜

Can be hand-pulled or harvested with tools depending on soil conditions.

Crop Storage Methods 🏠

Maize 🌽

Store in cribs dusted with pesticides or in silos for large-scale storage.

Groundnuts 🥜

Store in well-ventilated granaries after proper drying.