Crop Production and Microorganisms (Class 8)

What this worksheet covers

This is an eighteen-question practice worksheet on crop production and microorganisms for Class 8, written to the pattern of the SOF National Science Olympiad (NSO). It carries 24 marks and is designed to be attempted in 45 minutes, split across three sections — Scientific Reasoning, Applying What You Know and Achievers Section. Every question is multiple choice with exactly one correct option, and every one comes with a fully worked solution rather than just an answer key — so a child who gets one wrong can see where the reasoning went astray instead of only learning that it did.

Skills your child practises

• Applied problem-solving on crop production and microorganisms at Class 8 level
• Working accurately against a time limit, as the real paper demands
• Scientific Reasoning questions in the olympiad format
• Applying What You Know questions in the olympiad format
• Achievers Section questions in the olympiad format
• Reading worked solutions to find the step that went wrong

How to use it

1. 1There are 18 questions in this worksheet. All questions are compulsory.
2. 2Each question has four options (A), (B), (C) and (D). Exactly one option is correct.
3. 3Questions 1–15 carry 1 mark each. Questions 16–18 (Achievers Section) carry 3 marks each.
4. 4There is no negative marking. Study every diagram and table carefully.

Sample questions from this worksheet

A preview of what's inside Crop Production and Microorganisms (Class 8) — the PDF has the full set, and every question comes with a worked solution like these.

1. 1. Crops sown in the rainy season and harvested in autumn are called _______ crops.

   • ARabi
   • BCash
   • CZaid
   • DKharifcorrect
   Solution: Kharif crops are sown with the monsoon in June–July and harvested in September–October. Paddy, maize and cotton are kharif crops; wheat and gram are rabi crops.

2. 2. Why is crop rotation with a leguminous crop useful to a farmer?

   • AIt kills all the weeds
   • BIt makes the next crop grow taller only
   • CIt makes the soil drier
   • DThe legume's root nodules restore nitrogen to the soil, so less fertiliser is neededcorrect
   Solution: Cereals steadily use up soil nitrogen. Growing a legume in between means its Rhizobium-filled root nodules fix atmospheric nitrogen and restore it to the soil, so the next crop needs far less nitrogen fertiliser.

3. 3. Consider the following statements.(i) All microorganisms are harmful.(ii) Antibiotics are effective against bacteria but not against viruses.(iii) Vaccination protects a person by making the body produce antibodies in advance.Which of the statements is/are correct?

   • A(i) and (ii) only
   • B(ii) and (iii) onlycorrect
   • C(i) and (iii) only
   • DAll three
   Solution: Statement (i) is false — many microbes are useful, such as Lactobacillus in curd, yeast in baking and Rhizobium in soil. Statements (ii) and (iii) are both true, which is why antibiotics should never be taken for a common cold. Hence (ii) and (iii).