General Agriculture and Crop & Livestock Management Review

Comprehensive flashcard set covering general agricultural trends, crop husbandry, livestock management, genetics, economics, and agricultural engineering.

What are the five main stages in the historical development of agriculture?

1. Hunting and gathering
2. Domestication of plants and animals
3. Shifting cultivation
4. Settled agriculture
5. Commercial farming

What are the three land tenure systems in Botswana and their respective land coverage percentages?

1. Communal land tenure (71%)
2. State land tenure (23%)
3. Freehold land tenure (6%)

What are the soil characteristics and suitable uses of Land Capability Class I?

Characteristics: Deep fertile soil with good drainage, aeration, texture, water holding capacity; permeable to water; slope less than 2%; no erosion and capping. Suitable Use: Suitable for all uses; crop cultivation is the most profitable use; can be used for cropping every year.

In the internal leaf structure, what are the characteristics and main function of the palisade layer?

Structure: Consists of closely packed cylindrical-shaped palisade cells containing a high concentration of chloroplasts. Function: Absorbs light energy and serves as the primary site for photosynthesis.

Identify the labeled parts A through Q in the provided diagram of internal leaf structure.

A: Epidermal cell B: Guard cell C: Spongy cell D: Palisade cell E: Chloroplast F: Cuticle G: Palisade layer H: Xylem tissue I: Spongy layer J: Lower epidermis K: Phloem M: Air space N: Upper epidermis P: Vascular bundle Q: Stoma

What is the chemical equation for photosynthesis?

$$6\text{H}_2\text{O} + 6\text{CO}_2 \rightarrow \text{C}_6\text{H}_{12}\text{O}_6 + 6\text{O}_2$$

What is phototropism and how do auxins regulate shoot curvature towards light?

Phototropism is a plant growth movement in response to directional light. Unidirectional light causes auxins produced at the shoot tip to migrate laterally to the darker side. The higher auxin concentration on the darker side promotes faster cell elongation, resulting in a growth curvature towards the light.

What are the causes, symptoms, and control measures for Maize Streak Disease?

Cause: Virus spread by leafhoppers. Symptoms: White to yellow streaks (stripes) running parallel to leaf veins, stunted growth, and sterile inflorescence. Control: Plant resistant varieties, practice early planting, remove and burn infected plants, and spray with carbaryl.

What are the three main classes of insecticides categorized by their mode of action?

1. Contact insecticides: Act by physical contact with the body of the insect and are absorbed through the skin.
2. Stomach insecticides: Enter the insect through the mouth along with ingested food.
3. Systemic insecticides: Absorbed into the host plant tissue and translocated via sap, killing insects that feed on the sap.

What is topiary in landscaping, and what plant characteristics are necessary for creating topiary?

Topiary is the art of trimming bushes, hedges, and trees into decorative or geometric shapes. Plants suited for topiary have relatively small leaves, fine twigs, and respond to pruning by producing a very fine, dense crown.

What are the four compartments of the ruminant stomach shown in the diagram and their primary functions?

1. Rumen (1st stomach): Maintains microbial population, churns/mixes food, and acts as a fermentation/storage chamber.
2. Reticulum (2nd stomach): Sieves fine from coarse particles, traps foreign objects, and aids in regurgitation of cud.
3. Omasum (3rd stomach): Grinds food to a fine state and absorbs water.
4. Abomasum (4th stomach): True glandular stomach that secretes gastric juice containing digestive enzymes, HCl, and mucus.

What is the average gestation period of a cow?

282 to 283 days (approximately 9 months).

What is Newcastle Disease, how is it transmitted, and what are its prevention methods?

Newcastle Disease is a viral infection in poultry. Transmission: Spread bird-to-bird through mucus and faeces, via wild birds, infected eggs/carcasses, or contaminated feed and equipment. Prevention: Regular vaccination (Hitchner at 1 day old, Lasota at 3-4 weeks, Komarov at 4-20 weeks), culling infected birds, strict farm hygiene, and footbaths. There is no treatment or cure.

Detail the life cycle stages of a one-host tick as depicted in the provided cycle.

1. Eggs laid on ground; larvae hatch and climb onto host.
2. Larvae attach and feed on blood of host.
3. Engorged larvae moult and nymphs emerge.
4. Nymphs feed on blood.
5. Engorged nymphs moult and adults emerge.
6. Adults mate and feed on blood.
7. Engorged females drop to the ground to lay eggs.

What are decreasers in range management and why are they important?

Decreasers (desirable species) are the most palatable, nutritious, and competitive grass species that decrease in abundance as grazing pressure increases. Their dominant presence indicates a well-managed rangeland in good condition.

What is the difference between a homozygous and a heterozygous genotype?

Homozygous: A genotype consisting of two identical alleles for a particular trait (e.g., $TT$ or $tt$). Heterozygous: A genotype consisting of two different alleles for a particular trait (e.g., $Tt$).

What phenotypic ratio is obtained from a monohybrid genetic cross between two heterozygous parents ($Tt \times Tt$) under complete dominance?

A 3:1 phenotypic ratio (3 dominant phenotype : 1 recessive phenotype).

What is the Law of Demand?

The Law of Demand states that the quantity of a commodity demanded changes inversely with its own price: holding other factors constant, a higher price results in a lower quantity demanded, and a lower price results in a higher quantity demanded.

What is the Law of Diminishing Returns in agricultural economics?

The Law of Diminishing Returns states that in a production process, as one variable input is increased while keeping all other inputs constant, a point will be reached beyond which the additional (marginal) output gained from each additional unit of variable input begins to decrease.

How is the Gross Margin (GM) of a farm enterprise calculated?

$$\text{Gross Margin} = \text{Gross Income (Returns)} - \text{Total Variable Costs}$$

How do four-stroke petrol and diesel engines differ in their method of fuel ignition?

Petrol Engine: The compressed fuel-air mixture is ignited by an electric spark from a spark plug. Diesel Engine: Air alone is compressed to high pressure and temperature, causing injected diesel fuel to ignite spontaneously from the heat of compression.

What are the four sequential strokes in a four-stroke internal combustion engine cycle?

1. Induction (intake) stroke
2. Compression stroke
3. Power (combustion) stroke
4. Exhaust stroke