Plants

Plant reproduction and protection

Plant reproduction and protection at this grade is how new cultivars reach a field, and how the crop is kept alive until harvest.

CAPS

Grade 12 · Agricultural Sciences · Plants

Agricultural Sciences splits animals from plants, soil and management.

  • The papers

    Paper 1 is animal nutrition, animal production, reproduction and protection. Paper 2 is soil science, plant studies, and agricultural management. Each paper is 150 marks.

  • How to write it

    Use the farming term, then the reason: a deficient mineral, a symptom, a management practice, and why it changes the yield or the health of the animal. A list with no cause does not explain.

  • How a marker reads it

    A common mix-up is to spray first and rotate never, or to save seed from a hybrid and expect the same plants.

Data-response questions want you to read the table first. A general paragraph about farming that ignores the numbers scores as if you did not see them.

light

Diagram

Worked theory

Worked theory. A tomato cultivar that resists a soil fungus, grown from certified seed, in a bed that grew tomatoes last year and the year before. The resistance helps, but the fungus is already in that soil, so the plants still struggle. A rotation that puts a crop from another family in the bed for a season drops the fungus. Spraying the leaves does not fix a fungus that lives in the root zone. The theory joins the two ideas: the seed carries the resistance, the rotation lowers the enemy. One without the other is a half measure.

More worked examples

  • Tomatoes in the same bed

    A resistant cultivar still fails in a bed that grew tomatoes for three years, because the fungus is already in the soil. A spray on the leaves does not reach it. One season of cabbage, a different family, in that bed drops the fungus. The resistant seed still matters the year the tomatoes return. Seed without rotation, or rotation without the resistant seed, each leave one of the two causes standing.

  • A count before a spray

    A tomato grower counts caterpillars on 20 plants. Below the threshold she does nothing, because a wasp is already parasitising some of them. Above the threshold she sprays once, then counts again. Spraying every Friday, whether or not the count is high, kills the wasp as well and the next generation of caterpillars is harder to kill. The threshold is the theory. The calendar spray ignores it.

In ordinary words

Sexual reproduction shuffles genes and gives the breeder variation to select. Vegetative reproduction copies a good parent. Certified seed is that choice, cleaned and named. Protection is the set of practices that stop pests, diseases and weeds undoing it: rotation, resistant cultivars, scouting, and chemicals only when the others are not enough. Crop rotation breaks the life cycle of a pest that needs one host.

In South Africa

A school bed of tomatoes after tomatoes, sick in the soil, is the argument for rotation.

Part 1 / 4

What it is

Plant reproduction and protection at this grade is how new cultivars reach a field, and how the crop is kept alive until harvest.

More worked examples

Board walkthroughs on this topic. Open one, copy the working, then try the next.

Example 1 / 20

Explain Integrated Pest Management (IPM).

How we got there

Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.

Explain in another language · 11

1. What is the question asking?

Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: Explain Integrated Pest Management (IPM).

Before any working — hunt first

Given

Numbers and units already in the sentence: no numbers yet — only a name, a diagram, or a worded unknown. Copy each one into a column. A name without a number is not given.

Missing

After you copy the given, the letter that still has no number is missing. The paper is pointing at: Explain Integrated Pest Management (IPM). Circle that word — that is the missing variable.

Find

We are required to find: Explain Integrated Pest Management (IPM). Write that as a symbol on the left, with a question mark, before you touch a formula.

Calculate

What we need to calculate: Combine methods. Then substitute the given, one line at a time, to get Explain Integrated Pest Management (IPM).

In other words — as if you have never seen this before

If you have never seen this before: Combine methods. We will name a method in words, write the formula with no numbers, then substitute one line at a time.

2. What do we already know?

IPM.

3. Which method — and why this one?

Combine methods.

4. Step-by-step working

  1. 01 / 08

    Step A — Read the question twice

    Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.

    Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.

  2. 02 / 08

    Step A2 — Hunt: Given, Missing, Find, Calculate

    Given: Numbers and units already in the sentence: no numbers yet — only a name, a diagram, or a worded unknown. Copy each one into a column. A name without a number is not given. Missing: After you copy the given, the letter that still has no number is missing. The paper is pointing at: Explain Integrated Pest Management (IPM). Circle that word — that is the missing variable. Find: We are required to find: Explain Integrated Pest Management (IPM). Write that as a symbol on the left, with a question mark, before you touch a formula. Calculate: What we need to calculate: Combine methods. Then substitute the given, one line at a time, to get Explain Integrated Pest Management (IPM).

    Why this step: Do not name the letters yet. First hunt: what already has a number (Given), what has no number (Missing), the word the paper wants (Find), and which formula still contains the missing letter (Calculate).

  3. 03 / 08

    Step B — Write the given in a column

    IPM.

    Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.

  4. 04 / 08

    Step C — Name the method in words

    Combine methods.

    Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.

  5. 05 / 08

    Explain

    Monitor pests and use a mix of biological (ladybirds for aphids), cultural (crop rotation), mechanical and, only if needed, chemical controls.

    Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.

  6. 06 / 08

    Step G — Sense-check the size

    Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.

    Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.

  7. 07 / 08

    Step F — Box the answer with its unit

    IPM combines methods to keep pests below the economic threshold.

    Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.

  8. 08 / 08

    Step H — What the marker is looking for

    On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.

    Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.

5. The answer

IPM combines methods to keep pests below the economic threshold.

Copy onto your answer sheet — in this order

Answer: IPM combines methods to keep pests below the economic threshold.

6. Check it like a marker

Reduces chemical use and resistance.

7. A trap first-timers fall into

First-timers often grab the first formula they remember, mix units (cm with m, minutes with seconds), or drop a minus sign. Write the formula in words first: “this equals that, because…”

Ntsako · fx-991ZA PLUS. Tap to calculate.