Download App

Natural Resources — Science STD 9 — Question

Gujarat BoardEnglish MediumSTD 9ScienceNatural Resources3 Marks
Question
What is the composition of red soil?
✓

Answer

Red soil is rich in iron oxide, but deficient in nitrogen and lime. Its chemical composition generally includes non-soluble material $90.47 \%$, iron $3.61 \%$, aluminium $2.92 \%$, organic matter $1.01 \%$, Magne­sium $0.70 \%$, lime $0.56 \%$, carbon di-oxide $0.30 \%$, potash $0.24 \%$, soda $0.12 \%$, phosphorus $0.09 \%$ and nitrogen $0.08\ %$. Its colour is mainly due to ferric oxides occurring as thin coatings on the soil particles while the iron oxide occurs as haematite or as hydrous ferric oxide, the colour is red and when it occurs in the hydrate form as limonite the soil gets a yellow colour. Ordinarily the surface soils are red while the horizon below gets yellowish colour.

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

More "Que-Ans (Each of 3 Mark )" from Natural Resources→Natural Resources — all question types→Science STD 9 question papers→Gujarat Board STD 9 question papers→Gujarat Board question paper generator→

Similar questions

Match the following columns with correct answer.
 
Organism/ Bacteria
Disease
a.
Leishmania
Worm
b.
Staphylococci
Kala-azar
c.
Trypanosoma
Acne
d.
Ascaris lumbricoides
Sleeping sickness
→
The scientists now say that there are actually five states of matter $A, B, C, D$ and $E$. The state A has a fixed volume but no fixed shape. The state B can be compressed very easily by applying pressure and state $C$ has a fixed shape as well as a fixed volume. The state $D$ is mixture of free electrons and ions whereas state E is named after an Indian scientist and a famous physicist.
  1. Name the physical states $(i) A\ (ii) B\ (iii) C\ (iv) D$, and $(v) E$.
  2. Name one substance belonging to state $C$ which can directly change into vapours on heating. What is this process known as?
  3. Name one substance which normally belongs to state B but whose solid form changes directly into gaseous state.
  4. Name the most common substance belonging to state $A$.
  5. Which state of matter makes the sum and other stars to glow.
→
List any two differences between infectious and noninfectious diseases. Write any one example of each disease.
→
Which group of organisms have segmented worms? Give it’s two major characteristics.
→
A motorboat starting from rest on a lake accelerates in a straight line at a constant rate of 3.0m/ s−2 for 8.0s. How far does the boat travel during this time?
→
What were the reasons behind the occurrence of green and white revolutions?
→
Name one:
  1. Inexhaustible resource.
  2. Renewable exhaustible resource.
  3. Nonrenewable exhaustible resource.
→
Explain why particles of a colloidal solution do not settle down when left undisturbed, while in the case of a suspension they do.
→
Why does our palm feel cold when we put some acetone (or perfume) on it?
→
Define green revolution, what are the common objectives of crop improvement?
→