Introduction to Agriculture Flashcards

Course Overview and Introduction

SAE 101: Introduction to Agriculture is a $15$-point credit course at The University of Goroka lecturer by Binel Voyorite (Mrs). The course covers agriculture as an art, science, and business focused on food production in Papua New Guinea (PNG).

• Agriculture Defined: From Latin Ager (field) and Cultura (cultivation). It encompasses the cultivation of soil, crop production, and livestock raising.
• Agricultural Spheres: Earth-soil, air, and water.
• Key Components (PNG Stats):
  • Crops: $54\%$
  • Livestock: $41\%$
  • Fisheries: $4.5\%$
  • Forestry: $0.5\%$
• Economic Impact: Agriculture contributes approximately $25\%$ to the GDP, provides $80\%$ of foreign exchange, and employs $80\%$ of the PNG labor force.

Soil Science and Management

Soil is a natural body differentiated into horizons, functioning as an anchorage for roots and a storehouse for nutrients/water.

• Soil Composition:
  • Minerals: $45\%–49\%$
  • Water: $2\%–50\%$
  • Gases (Air): $2\%–50\%$
  • Organic Matter: $1\%–5\%$
  • Microorganisms: $<1\%$
• Soil Texture: Classified by particle diameter:
  • Sand: $0.05\text{--}2\,mm$
  • Silt: $0.002\text{--}0.005\,mm$
  • Clay: $<0.002\,mm$
• Soil Profile (Horizons):
  • O-Horizon: Organic layer ($20\%$ organic matter).
  • A-Horizon: Topsoil/root zone; zone of eluviation.
  • E-Horizon: Zone of greatest leaching.
  • B-Horizon: Subsoil/zone of illuviation (accumulation).
  • C-Horizon: Substratum/parent material.
  • R-Horizon: Bedrock.
• Management Practices: Mulching (organic/artificial), Crop Rotation (legume vs. non-legume), Cover Cropping, and Land Fallowing ($3\text{--}5$ years currently due to population pressure).

Crop Production and Management

Crop production began approximately $9000$ years ago. Classification occurs through scientific (Linnaeus Taxonomy) and artificial systems.

• Hierarchy: Kingdom → Division → Class → Sub-class → Series → Order → Family → Genus → Species → Variety.
• Practices:
  • Tilling/Ploughing: Loosening soil to improve aeration and water retention.
  • Sowing: Methods include broadcasting or using seed drills.
  • Fertilization: Using organic manure (cow dung, compost, vermicompost) or chemical fertilizers (e.g., NPK).
  • Irrigation: Drip systems or sprinkler systems.
  • Harvesting: Separating grains via threshing and winnowing.

Crop Protection: Pests and Diseases

• Weeds: Undesirable plants like Parthemum (carrot grass).
• Pests: $8$ destructive orders including Lepidoptera (moths/butterflies), Coleoptera (beetles), and Hemiptera (aphids/bugs).
• Plant Diseases: Caused by pathogens such as Fungi, Bacteria, Viruses, Viroids, Phytoplasmas, and Nematodes.
• Symptoms: Blights, powdery/downy mildews, wilts, galls, and mosaics (virus indicators).

Livestock in PNG

Livestock includes domestic quadrupeds, poultry, and insects like bees.

• Pre-Colonial Introduction: Pigs (Sus scrofa vittatus and Sus selebensis), New Guinea Singing dogs, and Chickens.
• Post-Colonial Introduction: Cattle (Bos taurus & B. indicus), Buffalo (Bubalus bubalis), Sheep (Highlands Halfbred), Goats, and Rabbits (New Zealand White and Canberra Half-lop).
• Management: Involves breeding, fodder production, housing, and disease control.

Meteorology and Climate Change

• Weather: Short-term day-to-day state of the atmosphere.
• Climate: Long-term prevailing conditions.
• Temperature in PNG: Influenced by altitude via the lapse rate ($0.5\,^{\circ}C$ per $100\,m$ increase).
• Rainfall: Varies significantly; Lae ($4700\,mm$) vs. Port Moresby ($1300\,mm$).
• Climate Change: Global mean temperatures have risen $0.8\,^{\circ}C$ since the late $1800s$. Evidence in PNG includes rising sea levels in Mortlock Island and coastal crops (e.g., coconut) bearing at higher altitudes.

Genetics and Breeding

• DNA Bases: Adenine ($A$), Cytosine ($C$), Guanine ($G$), and Thymine ($T$).
• Mendelian Laws:
  1. Law of Dominance: Dominant alleles ($R$) mask recessive alleles ($r$).
  2. Law of Segregation: Gene pairs separate during gamete formation.
  3. Law of Independent Assortment: Alleles of different genes are inherited independently.

Farm Mechanization

Levels include Hand tool technology, Draught animal technology, and Mechanical power technology.

• Basic Machines: Lever, Pulley, Wheel and Axle, Inclined Plane, Screw/Gears, and Wedge.
• Mechanical Advantage ($M.A.$): The ratio of the load ($W$) to the effort ($F$).

Questions & Discussion

• Tutorial Question: Why do we plant leguminous plants in fallow land?
• Response: Legume crops add nitrogen to the soil, helping to restore fertility during the resting period.
• Tutorial Question: Define organic farming.
• Response: Farming that utilizes techniques like crop rotation, green manure, and compost while excluding synthetic fertilizers.
• Tutorial Question: Explain the reason for studying the insect life cycle.
• Response: It identifies the most vulnerable stage of the pest for effective integrated pest management.