Study Notes on Crop Production

Light Africa for Humanity - Crop Production

Important Guidelines

  • Be open-minded

  • Listen carefully

  • One conversation at a time

  • Respect the opinions of others

  • Provide constructive feedback

  • Build on the ideas of others rather than dismantling them

  • Take risks and share new ideas

  • Have fun and enjoy the experience!

Delivery Mode

  • Blended approach incorporating both physical attendance and online participation

  • Attendance for lectures is compulsory

  • Active class discussions encouraged

  • Refer to module guide for more details

THEME 1: INTRODUCTION TO CROP PRODUCTION

Theme 1 Objectives

At the end of this unit, the student should be capable of:

  • Identifying the centers and origins of most crops

  • Distinguishing between indigenous and introduced crops in Africa

  • Classifying crops based on agronomic and special-purpose criteria

1. HISTORY AND DEFINITION OF AGRICULTURE

  • Early humans were primarily gatherers and hunters, consuming fruits and seeds.

  • Farming practices began approximately 9000 BC, marking the transition from foraging to agriculture.

  • The first crops cultivated included cereals like wheat, barley, sorghum, and millet.

  • Domestication of plants allowed for crop production to supplement natural food sources, marking the beginning of agriculture.

  • The essential elements of crop production have remained relatively unchanged over thousands of years.

Key Features of Crop Production

  1. Gathering and preserving seeds of desired crop plants

  2. Eliminating unwanted vegetation from planting areas

  3. Preparing the soil to create a suitable seedbed

  4. Timing planting to align with favorable seasonal and weather conditions

  5. Managing weeds and protecting crops from pests and diseases

  6. Harvesting, processing, and storing the crop yield

Historical Practices

  • Early cultivators grew a limited variety of crops primarily consisting of cereals, practicing continuous farming until yields decreased, leading to land rotation or fallowing every two to three years.

  • Traditional pest management involved manual removal of insects, supplemented by ritual practices to ward off diseases.

  • The introduction of various mineral or organic substances (e.g., sulphur, brine, soap) was used to treat crops against disease.

2. ORIGIN OF CULTIVATED CROPS

General Overview

  • All cultivated plants were derived from their wild ancestors.

  • The timing and location of the domestication of many crops remain poorly understood.

  • Cultivated crops spread globally through migration and human adaptation, introducing both indigenous and foreign species to different regions.

A. Centers of Origin of Cultivated Crops

  • Cultivation centers were characterized by suitable climates and populations.

  • Vavilov's Centers of origin reported include:

    • China

    • India/Indo-Malayan

    • Central Asia

    • Near East

    • Mediterranean regions

    • Ethiopia (African Center)

    • South Mexico and Central America

    • South America

B. Contribution of Different Centers

  1. Chinese Center: Known for species like Brassica campestris, Glycine max, and Oryza sativa (in secondary status).

  2. Indo-Malayan Center: Significant for crops like Cocos nucifera, and Saccharum officinalis.

  3. Indian Center: Important for Oryza sativa and Phaseolus mungo.

  4. Central Asia Center: Notable crops include Allium cepa and Daucus carota.

  5. Near Eastern Center: Known for Hordeum vulgare, Vitis vinifera, and others.

  6. Mediterranean Center: Crops include Avena spp., Olea europaea, and more.

  7. African Center: Includes Gossypium spp., Hibiscus spp., and Coffea spp.

  8. Central America and Mexican Center: Includes crops like Zea mays and Agaves spp.

  9. South American Center: Notable for tuberous crops such as Solanum spp. and Arachis hypogaea.

C. Spread of Cultivated Crops

  1. Natural Means: Seed dispersal via wind, water, and animal movement.

  2. Human Migrations: Farmers take crops with them to provide food security.

  3. World Trade Expansion: Introduced American crops (like maize and potatoes) to global markets.

  4. Agricultural Research Collaboration: Exchange of seeds between research institutions enhances crop diversity.

D. Indigenous Crops of Africa

  • Key indigenous cereals: Bulrush millet (Pennisetum typhoides), Guinea corn (Sorghum bicolor), Rice (Oryza glaberrima), etc.

  • Grain legumes include Cowpea (Vigna unguiculata) and Pigeon pea (Cajanus cajan).

  • Notable oil seeds: Oil palm (Elaeis guineensis), Niger seeds (Guizotia abyssinica).

  • Other indigenous crops include varieties of yam, fiber crops like cotton, and other vegetation.

E. Introduced Crops in Africa

  • Important introduced cereals: Rice (Oryza sativa), Wheat (Triticum aestivum).

  • Significant legumes: Groundnuts (Arachis hypogaea), Common bean (Phaseolus vulgaris).

  • Roots/tubers include Cassava (Manihot esculenta) and Sweet potato (Ipomoea batatas).

  • Included are oil crops like Sesame (Sesamum indicum) and drug crops like Tobacco (Nicotiana tabacum).

3. CROP CLASSIFICATION

Important Terminology

  • Taxonomy: Organized system of descriptive plant classification.

  • Nomenclature: System for assigning names to plants.

  • Binomial nomenclature: Naming system using two terms (genus and species) introduced by Carl Linnaeus.

Reasons for Classifying Crops

  • Enables order and organization

  • Aids logical naming, as common names vary significantly across regions.

  • Helps in understanding growing conditions, soil requirements, and adaptability.

Basis for Classification

  • Aristotle: Classified by structure and size (herb, shrub, tree).

  • Linnaeus: Focused on structural similarities of species.

  • Modern Classification: Based on phylogenetic relationships (evolution).

The International Code of Botanical Nomenclature (ICBN)

  • Classifies based on:

    • Botanical

    • Descriptive

    • Agricultural

A. Botanical Classifications

  • Bases classification on plant part similarity and flower structure.

  • Linnaeus established a standardized naming system in 1753, called the Binomial System.

    • Example: Scientific name of tomato: Solanum lycopersicum L.

  • Classifications follow the hierarchy:

    • Kingdom

    • Phylum/Division

    • Class

    • Order

    • Family

    • Genus

    • Species

Key Examples of Botanical Classification

  • Examples, such as cereal crops (Zea mays) and legumes (Vicia faba), reflect this detailed classification system.

B. Descriptive Classifications

Based on:

  1. Mode of reproduction (sexual/asexual)

  2. Life span (annuals, biennials, perennials)

  3. Growth habit (herbs, vines, trees)

  4. Leaf retention (evergreen vs. deciduous)

  5. Mode of pollination (self-pollinated vs. cross-pollinated)

Key Insights on Life Span

  1. Annuals: Complete lifecycle within one growing season (e.g., rice, corn).

  2. Biennials: Require two seasons for lifecycle completion (e.g., onion).

  3. Perennials: Live indefinitely and produce seeds annually (e.g., trees).

C. Agricultural Classifications

  • Based on agricultural use:

  1. Agronomic (Field) Crops: Staples like rice, corn, legumes.

  2. Horticultural Crops: Fruits, vegetables, and ornamentals.

D. Other Important Classifications

  • Crops can be grouped based on water requirements, root depth, ecological adaptation, and special uses such as cover, catch, companion crops, and insect repellents.

Additional Notes

  • Classification aids in understanding climate adaptability, soil preferences, and optimal growth conditions for various crop types.

References

  • GREEN EMPIRE. 2016, Licensure Examination in Agriculture Reviewer (Crop Science)

  • TAMAYO NV and AGUSTIN AL. 2017, Classification of crops. 2017 ALE Review, Department of Crop Science, College of Agriculture, Central Luzon State University.

  • Other scholarly texts on agriculture and crop science are listed for further reading.